I agree with AJ Harran on the flexure issue. From the vantage point you set the camera up at, I could tell every time you applied pressure on the square hole the material flexed, which looks like it compresses the sides, reducing the freedom for the cutter to wobble front-to-back. Anyway, very educational video for me. Thanks!
Great Video Tom- Can't wait to read the comments from all the 'Broach-guys' to see the shortcuts. Happy holidays to you Tom, your family and all the Oxen! 😃👍
Thank you Tom and all those involved in the efforts and production of this channel. Merry Christmas, Happy Holidays and Happy New Year to all. May the new year bring you, your families and friends much health, wealth, happiness and peace.
Now that is a really neat tool! Thanks for the video. In the case of the larger square tool, perhaps a step up process would be in order. Working from smaller squares up to the final....maybe?
For the larger square, I'd recommend drilling out the corners with smaller holes before drilling out the pilot in the center,. Still able to cut a full form square but with much more cutting clearance so that the broach doesn't have to push that much metal.
excellent review, always wondered how the hex holes were sunk. thanks for the know how Tom. great tool , I wish the maker every success and merry Christmas to you guys.
It seems to me that cutting pressure is proportional to starting hole diameter, broach shape and material. Getting the percentage correct between the hole size and the "across corner" diameter is the trick. Thanks for the tool review Tom, and thanks Brandon for offering it up for testing.
Nice review Tom thanks for the test. Going at it kind of cold like that you suddenly find out what you don't know about the tool's little quirks like hole size and perhaps even speed might be a factor.
Hi Tom, I have been reading your book "Metalworking: Doing it Better" and it is excellent! You put so many good tips and stories in there, and it is easy to read. (Especially with all of the pictures)
Dam it! it's too late to have Santa bring me one for Christmas. Very very nice tool and is at the top of my "must have" tools to buy! Great review Tom and congrats to you Brandon for producing a good functional tool!👍👍
Rigidity, Your spindle is oscillating. Thus reducing the cutting action. This is a huge cutter for the size of holder and rigidity of set up. I have difficulty with a 1/2" square broach and usually chip the broach using a vertical mill. I have never tried a 5/8" square broach. This is a beautiful Rotary Broach holder. Great Video.
Hi Tom, We use several of the rotary tools in production (CNC) for 3/4" square drive socket head aluminum bolts (M24 x 3) and 5/16" hex outside for drive end on some M10 x 1.75 all-threaded 303 stainless studs. Occasionally some other "specialty" sizes for tooling applications are used in the Bridgeport mills. When used in Bridgeport, we use the knee with the spindle fully retracted and locked. The knee has a little better 'control' and not risking an overload of the quill drive. Oh, and YES, it DOES take significant pressure to drive a broach at "full form". Effectively you DO have to develop punching pressures (albeit incrementally) to move that metal. Ken
Tom, it seems to me that much like a standard push broach, you should have at least two broaches to complete the flats. Think one round hole and two broached. Wow, nice tool, great review!
I'd been struggling to get a clear mental image on how a rotary broach actually works but this is the best video yet (out of dozens) because the large square rotary broach on the mill really exaggerates what's going on! It seems counterintuitive but when someone struggles to achieve a good result with a proven method I feel you get a better understanding of what the process actually entails.
Nice video, cheers Tom. Just a thought from seeing the plate bending due to the pressure you were putting on when using the larger broach. You could have drilled out the corners as well with a smaller drill to remove most of the material, hopefully making it a bit easier to push through. Or maybe using a small end mill to rough out the shape to a smaller square. Dan.
What a neat tool, at least for small broaches, I'd love a torx one. Mate you are not wrong about the force used on that large square, I can see the work bowing :)
Think more support under the work piece for the larger broach will help since the work piece is flexing and adsorbing the 'wobbling' action which probably is making it difficult to cut.
Would it work just drilling out the displaced metal when the going gets too heavy before resuming broaching rather than making the hole larger? Also, will it cut steel?
Merry Christmas Tom to you and your Wife I have learned allot very quickly and have you to thank so have a great day and hope to see you in the new year. Thank you
First time I can comment in real time now that I'm caught up. Really enjoying Adam Booth's channel. Thought on your "Meatloaf" series you could tell some more stories -- like "we workin' outside today?" You could call them a "side of Ox Tale Soup." Wishing you and Mrs. Ox a very Merry Christmas, Happy Holidays and a Happy New Year. Oslowe (Mom from Piedmont)
Perhaps with 4 holes drilled close to the corners you could get that square broach pushed thru without such an oversized hole. This is in Alum, no chance it would go thru steel like this.
That's what I was thinking. You'd have to put the c/sink on first, then cut a square with (rounded corners) using a roughing end mill(?) to make life easier on broach. I guess it would be no more alignment effort than setting up to broach a smaller hole. Provided you have the focal length correct, this would greatly extend the maximum broach size for a machine of this stiffness/max tool load limit.
Had wondered how polygonal holes were made in metal, and now I know one more method than before (multi-ton presses was the way I've seen it done). Then again, I'm just a UA-cam watcher who has never ever set foot in a metal shop :)
Great tool and demonstration. Thank you for showing us. We probably aware of a higher percentage of unwanted cross sectional area in converting a round hole into a square compare to hex. The adjacent sides of a 90-deg corner tends to more converge waste material in a direction compare to hex of 120-deg. The forward face, profile, of the cutter may not be designed/finished to extract amount of material of that kind. The lube did little to help extraction, waste material began gum up in each corner, soon combine and piled with the upcoming material, and eventually work hardened into a nasty bump have prevented completion of this cut. Considerations : Could change to heavy duty lube such as grease improve it. The face profile has two concave regions, area with shallow and steeper (concave, radius) angles, reduce the surface area in the shallow region, and to reduce concave radius to steeper region, for material such as aluminum. In addition, we may break the broaching in two cycles, starting with one size smaller die before the finishing size which brings up the tooling and cycle cost.
+YK Chan Hi Chan, You are correct. The starting hole for a square needs to be much larger. The broach did have concave clearance in end but not enough for the amount of material I was attempting to push. Thanks for the comment. Cheers, Tom
Nice review Tom, thanks. The large broach seemed to be approaching the max for your machine stiffness. For most work I guess the feel for the machine is all the feedback an experienced machinist needs, are there fussy jobs that need more feedback? We've made load cells in the past for doing friction stir welding to get constant load on the tool shoulder.
I am not even a machinist novice but I wonder if drilling out the four corners with small bits and following that with then drilling out the center would allow the broach to work its way through. Just a thought.
I love that tool! The finish on the holes look nice. When I do stuff like that, I punch the holes. It's faster to punch, but the burrs are large, and the hole finish isn't always great. Another thing is, that to punch holes, I have a big hydraulic that only does one thing... Do you need a milling machine for this type of broaching, or would a drill-press be rigid enough?
I've been playing around with Rotary broaching a Keyway, Square is a lot of removal. Seems like once I get a Burr, it has to work exponentially harder (meaning, that mostly it doesn't).
That was a very helpful video, thanks Tom, a rotary broach has been on my list of tools to make for a long time now, but keeps getting pushed aside. I think the asking price of this tool from DB customs is quite reasonable for those who don't want to roll their own (I have no connection btw). Yes it would however be a VERY good project ;) The large broach almost looked like it didn't have sufficient face relief and the chips were impeding the action by rubbing on the face. Given that it was a commercial broach I'm sure they know what they're doing, but had I ground that myself I'd be trying to relieve the centre more. It could well be a case where the aluminium wasn't doing any favours over steel for example, and a more brittle chip would curl over and not impede the progress of the tool. It would be interesting to try the same exercise in a different material. Would you consider 1.75" the most popular size for commercial broaches around this size, and do they go down to smaller sizes in that length too? While I'd I'd expect to grind my own tools, when I do finally get that rotary broach made, I would like to use a common tool length in case any exotic holes come up that would be too difficult to grind the tool for and I can just buy them off the shelf. Until now I didn't know they were in standard lengths, and guys I've seen have just been grinding them to suit their own tools, so that was great info. The shank itself looked like a pretty standard weldon type so it can be stripped from the work, so it makes me wonder if old end mills could find a new life? Thanks again for the interesting and fun videos of 2015 Tom, and all the best to you two metal-heads for the New Year and 2016.
Tom, I read that the bearings only last like 100 holes or so, doesn't that seem a little low to you? Can you see why that is the case? Perhaps a different bearing (taper roller bearings) would improve the life?
I think (from my armchair) that just re drilling the 2nd drill bit size for the square would have been sufficient just to clear the big chips, and as another viewer noted, there was a lot of flex in the part that could have been binding up the wobble action. Cool tool review and I'd like to see it working some steel.
Tool quality looks great. I was thinking that the material being "soft" was being displaced/folded over and forming an interior base stopping the cutting, thus the larger hole. A press broach has an area behind the tooth for shavings and the square has no such relief area. If the test was made on steel I wonder if the same type results would appear, that is where the material is not so "soft" ? Good video and good tool.
Hi With the big broach, do you think the rigidity of the mill has an effect on performance. I am thinking spring back might be lowering the broach speed of advance.
+Dennis Williams Hi Dennis, There was just too much material for the broach to cut. I should have drilled out the corners to relieve some of the pressure. Thanks for the comment. Cheers, Tom
I am surprised the broaches didn't come with a drill chart. I ordered one broach from Polygon Solutions and they sent the chart with it. I made my holder from a threaded tip live center. I think it is much more useful in the lathe than in the mill. I believe the maximum depth of cut is 3x diameter.
Tom, Thank you for the demo. I never knew what/how a rotary broach worked..now I do. I noticed that when you were cutting the square hole the alum scrap piece was flexing down. Wonder if that had any effect of negating the "vibrating" action of the broach. (about 23:10 or so). Regards, Eric
+esoomreltna Hey Eric, What you couldn't see is how hard I was pulling on the quill lever. I really should have drilled out the four corners prior to broaching. That was 1/2 thick alum to give you an idea how hard I was pulling. Thanks for the comment. Cheers, Tom
you can drill the corners with a smaller bit to help speed this up and still keep its square shape. removing material from the corners gives a little more wobble to the cutter.
Would broaching such relatively large sizes be made easier by some kind of two stage broach? i am assuming because of the larger area and the lower surface pressure causes the issue
+jusb1066 I had the same question. Looking at the thickness of those chips of the partial broach you can understand how the pressure needed increases. If you reduce the chip load it should make it easier.
+jusb1066 I was also wondering something similar, as in go up in stages until finish size is reached. The indexing may become a bit more tricky with this approach though. All in all looks be a great tool and well made. Cheers from John and seasons greetings to all from Australia.
You could hit the corners with a small drill bit then take the center out as well or use a small end mill to get it closer then broach it for good form.
If your going to cut a square hole. Use smaller square broaches and work your way up to the desired dimensions.. or use a step broach on a arbor press.
Cool tool. I would have liked to hear the difference in price (and maybe tool life) for the broaching bits vs. regular push or pull broaches. Straight broaches are available in hex or square (and also require slightly oversize holes), but will not work in a blind hole. There is also the relative price (and size - if you have a very small shop) of the rotary broach tool vs. some kind of press for pushing a straight broach. I have made one-off hex broaches by cutting the corners off a section of allen wrench. First remove most of the corners for the depth of the hole; drive it in with a hammer. Then cut that tip off and grind away a bit less of the corners; drive that in. Eventually you are driving in a bit of allen wrench with the full hex. Price: one allen wrench of the right size, and some time. You only get a couple of holes before the tool is ruined (allen wrenches aren't all that hard), but if a couple of hex holes is all you need, it works. You can do the same sort of thing with a bit of square key stock, but it is much more difficult to drive and you may need to recut the tool more than once for each step. It really helps to hold these broaching tools in a pair of Vise-Grips™; it keeps them straight and saves the fingers.
Hi,I would like to get the opinion from a professional machinist. I going to purchase a drill press and would like to know.is having a power down feed important.?Is it a feature on the drill press that's often used or is barely used?
Given that a square broach has to remove more material and that a larger broach has to remove more material, I would expect to start with a smaller size if a fully formed shape is needed. (I don't start with a 1" drill if I want to drill a 1" hole in stainless.) Great review.
Interesting video. Thanks for sharing. Where did you get that awesome little square (at 8:36). 99% of all the work I do is of fairly small scale. That would be really handy. I modeled one up, but I'd be interested to know where you found it.
Tom, Good tool review the wobble action really gets the job done. Off subject where can I get some info on Stan's squares? I really like that little square you were using to true up the broach. Merry Christmas, Jef
From my experience with morticing picture frame corners, try a smaller cut first and take progressively larger square cuts. It doesn’t seem like the waste has anywhere to go and clogs up the cut. We could never take the full cut with wood, and had to take smaller chunks at a time.
Hi mate. Have you used those same broaches with an other head, or was this the first time. What I'm getting at is, was this the quality of the head or something else. Those thing are also used for steel, right? If it has trouble getting through aluminium, than it does not hold much hope for steel. Should the wobble be adjustable? All the best to you and yours, Marcel.
Alas, DB Customs appears to be no more. I think drilling some small corners holes in the corners should help with that square brooch quite a bit. Another option would be to start with a smaller square broach, and then enlarge the hole to final size with that broach.
Very informative video. Like a lot of things, you can read about how a process works, but until you see it, you can't get a clear idea of how it works. Do the instructions say if the tool works on steel? Lot more applications for steel than aluminum. Anyway, thanks for a useful demonstration
tom the square broach did not fit in the box because maybe it isn't suppose to because its not the 1.75 inch long you stated that tool is designed fore
+dan rasmussen That's what I was thinking when he couldn't get the lid closed on that big square broach. I was thinking, you know, maybe that tool is just a bit oversized?
@@EVguru From the geometry of the wobble action of a rotating wobble broach holder, the distance from the leading edge of the tool back to the holder datum (ie where the shank joins the head) would be critical to the correct action, as Dan implies.
I agree with AJ Harran on the flexure issue. From the vantage point you set the camera up at, I could tell every time you applied pressure on the square hole the material flexed, which looks like it compresses the sides, reducing the freedom for the cutter to wobble front-to-back. Anyway, very educational video for me. Thanks!
I wasn't needing one of these until I watched this... Thanks! :)
Great Video Tom- Can't wait to read the comments from all the 'Broach-guys' to see the shortcuts. Happy holidays to you Tom, your family and all the Oxen! 😃👍
A very cool tool! I have never seen one in action before. That was a lot of fun! Thanks for the review!
Tom, for square broaches Slater recommends a pilot hole of 1.1 times the broach dimension, .693 for a .630 (5/8 nominal) broach.
so does that mean that you can't practically use the entire perimeter of the broach for cutting?
Nah, you need 2 stages of broaching on that square head.
I seen a guy do same diameter with a hand made dye and a vice. Slow is faster
You can also rough the corners with a smaller endmill.
From my family to yours a Merry Christmas and a very Happy New Year.
Awesome tool! Id like to have one of those around myself. Thanks for the cool tool review Tom.
Me too abom me to" looks ace, make one for us as a project, you do a abom size one Tom normal size. Merry Xmas. Robin
+Brandon Nichols You bet Brandon! Very pro work you have done there.
Everybody need a box with full set of heads! Just perfect as is! Thank You for review!
Thank you Tom and all those involved in the efforts and production of this channel.
Merry Christmas, Happy Holidays and Happy New Year to all.
May the new year bring you, your families and friends much health, wealth, happiness and peace.
Nice review, Tom.
Merry Christmas to you and your missus.
Thanks,
John
Great video. Definitely seeing the need for a rotary broach in my garage workshop. 👍
Very cool tool.. nice video ! and compliments to DB Customs
Now that is a really neat tool! Thanks for the video. In the case of the larger square tool, perhaps a step up process would be in order. Working from smaller squares up to the final....maybe?
For the larger square, I'd recommend drilling out the corners with smaller holes before drilling out the pilot in the center,. Still able to cut a full form square but with much more cutting clearance so that the broach doesn't have to push that much metal.
excellent review, always wondered how the hex holes were sunk. thanks for the know how Tom. great tool , I wish the maker every success and merry Christmas to you guys.
It seems to me that cutting pressure is proportional to starting hole diameter, broach shape and material. Getting the percentage correct between the hole size and the "across corner" diameter is the trick. Thanks for the tool review Tom, and thanks Brandon for offering it up for testing.
Good review Tom. Happy holidays to you and yours.
Nice review Tom thanks for the test. Going at it kind of cold like that you suddenly find out what you don't know about the tool's little quirks like hole size and perhaps even speed might be a factor.
Hi Tom, I have been reading your book "Metalworking: Doing it Better" and it is excellent! You put so many good tips and stories in there, and it is easy to read. (Especially with all of the pictures)
Dam it! it's too late to have Santa bring me one for Christmas. Very very nice tool and is at the top of my "must have" tools to buy! Great review Tom and congrats to you Brandon for producing a good functional tool!👍👍
Over all a very nice tool . I really like it Tom .. Thumbs up man !!
thanks for the review.. always thought it would be something that would be nice to have.
Great review! Merry Christmas to you and yours...
Rigidity, Your spindle is oscillating. Thus reducing the cutting action. This is a huge cutter for the size of holder and rigidity of set up. I have difficulty with a 1/2" square broach and usually chip the broach using a vertical mill. I have never tried a 5/8" square broach. This is a beautiful Rotary Broach holder. Great Video.
Merry Christmas Tom and have a great new year.
How much offset is in the wobble ?
Aluminum doesn't count, does it work on steel ?
Hi Tom, We use several of the rotary tools in production (CNC) for 3/4" square drive socket head aluminum bolts (M24 x 3) and 5/16" hex outside for drive end on some M10 x 1.75 all-threaded 303 stainless studs. Occasionally some other "specialty" sizes for tooling applications are used in the Bridgeport mills. When used in Bridgeport, we use the knee with the spindle fully retracted and locked. The knee has a little better 'control' and not risking an overload of the quill drive. Oh, and YES, it DOES take significant pressure to drive a broach at "full form". Effectively you DO have to develop punching pressures (albeit incrementally) to move that metal.
Ken
Tom, it seems to me that much like a standard push broach, you should have at least two broaches to complete the flats. Think one round hole and two broached.
Wow, nice tool, great review!
I'd been struggling to get a clear mental image on how a rotary broach actually works but this is the best video yet (out of dozens) because the large square rotary broach on the mill really exaggerates what's going on! It seems counterintuitive but when someone struggles to achieve a good result with a proven method I feel you get a better understanding of what the process actually entails.
Thanks for making this video, easy to watch and good information.
it looks like a lovely tool i made one a while back and considering the work involved its a good price
Looks solid, very American of you Brandon. When the day comes to get a "DB 'D'a 'B'roach" It'll be one of yours.
Thanks Tom, for the review.
Enjoyed...happy holidays Tom!....test piece is AL, any idea of performance in steel?
Thumbs up, A good honest test. If i had a mill, I would buy one.
Nice video, cheers Tom.
Just a thought from seeing the plate bending due to the pressure you were putting on when using the larger broach. You could have drilled out the corners as well with a smaller drill to remove most of the material, hopefully making it a bit easier to push through. Or maybe using a small end mill to rough out the shape to a smaller square.
Dan.
Tom, Could you tell me where you got that little speed square? I've never seen one that small
Hi Tom, That was a great tool review on what looks like a really nice tool. Have a Merry Christmas and Happy New Year Matt C.
What a neat tool, at least for small broaches, I'd love a torx one. Mate you are not wrong about the force used on that large square, I can see the work bowing :)
Think more support under the work piece for the larger broach will help since the work piece is flexing and adsorbing the 'wobbling' action which probably is making it difficult to cut.
+AJ Harran Yeah the plate was flexing quite a bit!
It may even be binding the broach.
Would it work just drilling out the displaced metal when the going gets too heavy before resuming broaching rather than making the hole larger?
Also, will it cut steel?
Merry Christmas Tom to you and your Wife I have learned allot very quickly and have you to thank so have a great day and hope to see you in the new year. Thank you
thanks tom, very fair review,
Cool tool, weebles wobble but they don't fall down. Merry Christmas and all the best in the New Year
First time I can comment in real time now that I'm caught up. Really enjoying Adam Booth's channel. Thought on your "Meatloaf" series you could tell some more stories -- like "we workin' outside today?" You could call them a "side of Ox Tale Soup."
Wishing you and Mrs. Ox a very Merry Christmas, Happy Holidays and a Happy New Year.
Oslowe (Mom from Piedmont)
one of the builds I want to do on my channel is a lathe rotary broach. it spins rather than wobbles and it rotates with the work.
Perhaps with 4 holes drilled close to the corners you could get that square broach pushed thru without such an oversized hole. This is in Alum, no chance it would go thru steel like this.
That's what I was thinking. You'd have to put the c/sink on first, then cut a square with (rounded corners) using a roughing end mill(?) to make life easier on broach. I guess it would be no more alignment effort than setting up to broach a smaller hole. Provided you have the focal length correct, this would greatly extend the maximum broach size for a machine of this stiffness/max tool load limit.
Had wondered how polygonal holes were made in metal, and now I know one more method than before (multi-ton presses was the way I've seen it done). Then again, I'm just a UA-cam watcher who has never ever set foot in a metal shop :)
Great tool and demonstration. Thank you for showing us.
We probably aware of a higher percentage of unwanted cross sectional area in converting a round hole into a square compare to hex. The adjacent sides of a 90-deg corner tends to more converge waste material in a direction compare to hex of 120-deg. The forward face, profile, of the cutter may not be designed/finished to extract amount of material of that kind. The lube did little to help extraction, waste material began gum up in each corner, soon combine and piled with the upcoming material, and eventually work hardened into a nasty bump have prevented completion of this cut.
Considerations : Could change to heavy duty lube such as grease improve it. The face profile has two concave regions, area with shallow and steeper (concave, radius) angles, reduce the surface area in the shallow region, and to reduce concave radius to steeper region, for material such as aluminum. In addition, we may break the broaching in two cycles, starting with one size smaller die before the finishing size which brings up the tooling and cycle cost.
+YK Chan Hi Chan,
You are correct. The starting hole for a square needs to be much larger. The broach did have concave clearance in end but not enough for the amount of material I was attempting to push. Thanks for the comment.
Cheers,
Tom
Nice review Tom, thanks. The large broach seemed to be approaching the max for your machine stiffness. For most work I guess the feel for the machine is all the feedback an experienced machinist needs, are there fussy jobs that need more feedback? We've made load cells in the past for doing friction stir welding to get constant load on the tool shoulder.
I am not even a machinist novice but I wonder if drilling out the four corners with small bits and following that with then drilling out the center would allow the broach to work its way through. Just a thought.
Tom, I think you should try the big square broach with better support under the work and use the knee instead of the quill...
Good review Tom! Maybe Santa will have that tool under my tree.
Take a drink every time this dude says “ok?”.
I love that tool! The finish on the holes look nice.
When I do stuff like that, I punch the holes. It's faster to punch, but the burrs are large, and the hole finish isn't always great.
Another thing is, that to punch holes, I have a big hydraulic that only does one thing...
Do you need a milling machine for this type of broaching, or would a drill-press be rigid enough?
tom great video on broaching .
Pretty reasonable. Nice demo
What happened to the baby bullet build ?
I wonder if you made a .63 rectangle with a 1/8" end mill. Probably easier on your spindle bearings.
looks very nice
How flat do you think the bottom of the borached shapr would be if it were used as a counterbore?
Is it possible that the cutting fluid is causing trouble? A hydraulic cushion, preventing the broach from cutting as well as possible?
I've been playing around with Rotary broaching a Keyway, Square is a lot of removal. Seems like once I get a Burr, it has to work exponentially harder (meaning, that mostly it doesn't).
That was a very helpful video, thanks Tom, a rotary broach has been on my list of tools to make for a long time now, but keeps getting pushed aside. I think the asking price of this tool from DB customs is quite reasonable for those who don't want to roll their own (I have no connection btw). Yes it would however be a VERY good project ;)
The large broach almost looked like it didn't have sufficient face relief and the chips were impeding the action by rubbing on the face. Given that it was a commercial broach I'm sure they know what they're doing, but had I ground that myself I'd be trying to relieve the centre more. It could well be a case where the aluminium wasn't doing any favours over steel for example, and a more brittle chip would curl over and not impede the progress of the tool. It would be interesting to try the same exercise in a different material.
Would you consider 1.75" the most popular size for commercial broaches around this size, and do they go down to smaller sizes in that length too? While I'd I'd expect to grind my own tools, when I do finally get that rotary broach made, I would like to use a common tool length in case any exotic holes come up that would be too difficult to grind the tool for and I can just buy them off the shelf. Until now I didn't know they were in standard lengths, and guys I've seen have just been grinding them to suit their own tools, so that was great info. The shank itself looked like a pretty standard weldon type so it can be stripped from the work, so it makes me wonder if old end mills could find a new life?
Thanks again for the interesting and fun videos of 2015 Tom, and all the best to you two metal-heads for the New Year and 2016.
Tom, I read that the bearings only last like 100 holes or so, doesn't that seem a little low to you? Can you see why that is the case? Perhaps a different bearing (taper roller bearings) would improve the life?
I think (from my armchair) that just re drilling the 2nd drill bit size for the square would have been sufficient just to clear the big chips, and as another viewer noted, there was a lot of flex in the part that could have been binding up the wobble action.
Cool tool review and I'd like to see it working some steel.
Tool quality looks great. I was thinking that the material being "soft" was being displaced/folded over and forming an interior base stopping the cutting, thus the larger hole. A press broach has an area behind the tooth for shavings and the square has no such relief area. If the test was made on steel I wonder if the same type results would appear, that is where the material is not so "soft" ?
Good video and good tool.
I wonder if a hammer drill used in hammer only mode, properly positioned can be used to do the job...
Hi
With the big broach, do you think the rigidity of the mill has an effect on performance.
I am thinking spring back might be lowering the broach speed of advance.
+Dennis Williams Hi Dennis,
There was just too much material for the broach to cut. I should have drilled out the corners to relieve some of the pressure. Thanks for the comment.
Cheers,
Tom
I am surprised the broaches didn't come with a drill chart. I ordered one broach from Polygon Solutions and they sent the chart with it. I made my holder from a threaded tip live center. I think it is much more useful in the lathe than in the mill. I believe the maximum depth of cut is 3x diameter.
nice video Tom, Thanks
great video...learned alot
Tom, Thank you for the demo. I never knew what/how a rotary broach worked..now I do. I noticed that when you were cutting the square hole the alum scrap piece was flexing down. Wonder if that had any effect of negating the "vibrating" action of the broach. (about 23:10 or so). Regards,
Eric
+esoomreltna Hey Eric,
What you couldn't see is how hard I was pulling on the quill lever. I really should have drilled out the four corners prior to broaching. That was 1/2 thick alum to give you an idea how hard I was pulling. Thanks for the comment.
Cheers,
Tom
would 4 smaller holes work better for the square broach?
you can drill the corners with a smaller bit to help speed this up and still keep its square shape. removing material from the corners gives a little more wobble to the cutter.
Thanks again Tom
Would broaching such relatively large sizes be made easier by some kind of two stage broach? i am assuming because of the larger area and the lower surface pressure causes the issue
+jusb1066 I had the same question. Looking at the thickness of those chips of the partial broach you can understand how the pressure needed increases. If you reduce the chip load it should make it easier.
+jusb1066 I was also wondering something similar, as in go up in stages until finish size is reached. The indexing may become a bit more tricky with this approach though. All in all looks be a great tool and well made. Cheers from John and seasons greetings to all from Australia.
+joandar1 he indexed it with a square, so I dont see why he couldn't have done that for each progressive size (-8
You could hit the corners with a small drill bit then take the center out as well or use a small end mill to get it closer then broach it for good form.
If your going to cut a square hole. Use smaller square broaches and work your way up to the desired dimensions.. or use a step broach on a arbor press.
Cool tool. I would have liked to hear the difference in price (and maybe tool life) for the broaching bits vs. regular push or pull broaches. Straight broaches are available in hex or square (and also require slightly oversize holes), but will not work in a blind hole. There is also the relative price (and size - if you have a very small shop) of the rotary broach tool vs. some kind of press for pushing a straight broach.
I have made one-off hex broaches by cutting the corners off a section of allen wrench. First remove most of the corners for the depth of the hole; drive it in with a hammer. Then cut that tip off and grind away a bit less of the corners; drive that in. Eventually you are driving in a bit of allen wrench with the full hex. Price: one allen wrench of the right size, and some time. You only get a couple of holes before the tool is ruined (allen wrenches aren't all that hard), but if a couple of hex holes is all you need, it works. You can do the same sort of thing with a bit of square key stock, but it is much more difficult to drive and you may need to recut the tool more than once for each step. It really helps to hold these broaching tools in a pair of Vise-Grips™; it keeps them straight and saves the fingers.
This isn’t second review in this video.
My thoughts? Are we dealing with work hardened material?
Could you run through with a smaller broach 1st? If you are even only close on orientation you could still get full form from the final size.
Hi,I would like to get the opinion from a professional machinist. I going to purchase a drill press and would like to know.is having a power down feed important.?Is it a feature on the drill press that's often used or is barely used?
nice tool!
also can you show its use in the lathe?
Given that a square broach has to remove more material and that a larger broach has to remove more material, I would expect to start with a smaller size if a fully formed shape is needed. (I don't start with a 1" drill if I want to drill a 1" hole in stainless.)
Great review.
There is the same for the BTR (hexagonal)?
Interesting video. Thanks for sharing.
Where did you get that awesome little square (at 8:36). 99% of all the work I do is of fairly small scale. That would be really handy. I modeled one up, but I'd be interested to know where you found it.
Hi Eric,
Stan over at Bar Z industrial makes and sells these. Check out his YT channel ShadonHKW. Thanks for the comment.
Cheers,
Tom
very interesting broach.
drill 4 smaller holes in the corners before doing the large hole in the middle, that'l give the machine a fighting chance
Probably worth to broach the big hole with a slightly smaller cutter first to take some of the bulk off.
PS: Merry Christmas!
Ox, at 16:57 ... The issue is it is hitting on the sidewalls of the tooling... It is hitting the "deck surface"; it is being limited in it's axis...
Tom,
Good tool review the wobble action really gets the job done.
Off subject where can I get some info on Stan's squares? I really like that little square you were using to true up the broach.
Merry Christmas,
Jef
+Jeff Bernstein www.barzindustrial.com/Products.aspx
Well done. I thought it was an honest, tell it like it is evaluation, without pandering to the maker for supplying a free tool.
From my experience with morticing picture frame corners, try a smaller cut first and take progressively larger square cuts. It doesn’t seem like the waste has anywhere to go and clogs up the cut. We could never take the full cut with wood, and had to take smaller chunks at a time.
Hi mate. Have you used those same broaches with an other head, or was this the first time. What I'm getting at is, was this the quality of the head or something else. Those thing are also used for steel, right? If it has trouble getting through aluminium, than it does not hold much hope for steel. Should the wobble be adjustable? All the best to you and yours, Marcel.
What would happen if you drilled 1/8" holes inside the corners of the square then the center hole
If you are an experienced machinist that's the first thing that pops in your head
Maybe try using a smaller broach of the same shape, then stepping up to the full form broach for the finishing pass?
Alas, DB Customs appears to be no more. I think drilling some small corners holes in the corners should help with that square brooch quite a bit. Another option would be to start with a smaller square broach, and then enlarge the hole to final size with that broach.
Very informative video. Like a lot of things, you can read about how a process works, but until you see it, you can't get a clear idea of how it works. Do the instructions say if the tool works on steel? Lot more applications for steel than aluminum.
Anyway, thanks for a useful demonstration
tom the square broach did not fit in the box because maybe it isn't suppose to because its not the 1.75 inch long you stated that tool is designed fore
+dan rasmussen That's what I was thinking when he couldn't get the lid closed on that big square broach. I was thinking, you know, maybe that tool is just a bit oversized?
+dan rasmussen I think the problem is the length of the head, not the whole tool.
@@EVguru From the geometry of the wobble action of a rotating wobble broach holder, the distance from the leading edge of the tool back to the holder datum (ie where the shank joins the head) would be critical to the correct action, as Dan implies.