Easy Rotary Broach Tool Grinding
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- Опубліковано 11 лип 2020
- Alternate methods of rotary broach tool grinding. Hex and square broach tools can be made using a lathe, mill or bench grinder
A rotary broach lets you cut internal (and external) features such as a hex, spline or a square into an existing hole. This is very useful to make custom tools.
Rotary Broach build here:
• Detailed Rotary Broach...
Built for the TMC2020 competition
Plans available here:
www.etsy.com/au/listing/83195...
Note; plans are revised based on my prototype, and are subject to change with improvements.
Drop a comment or an email (go to my 'about page' for email address) if you are interested in buying a rotary broach tool or just the tool bits themselves. If I get enough interest, I will make a batch.
Follow me on instagram for behind the scenes and other random stuff
/ tommygun_machining
Steel used is from Tyne Valley Metals. Check them out for a variety of materials:
www.ebay.com.au/str/tynevalle...
/ tynevalleyenterprises
I plan to do more videos soon where I show where certain steels provide benefit. Stay tuned.
Joe Pieczynski's tool grinding video here:
• Can You Grind Tools on...
Eccentric Engineering (Bench grinder sharpening system and more)
www.eccentricengineering.com.au/
Crag's workshop demonstrated a simpler bench grinder method here:
• Making a rotary broach...
MAKE SURE YOU COVER YOUR WAYS BEFORE GRINDING
I didn't cover my lathe as well as I should have but I made sure to thoroughly wipe everything afterwards - Наука та технологія
PS, the emphasis on the plans is because I've been getting a LOT of messages and emails about plans despite mentioning where to get them. I'm trying to save answering the same thing repeatedly
I've bought those plans and they're good value. Very high quality, nicely drawn and will be easy to work from. Thanks Tom.
I love the out of the box thinking on the lathe and mill setup. With the grinder, I know there are probably infinite ways to do it. The simplest way I can think of would be to use either a collet block (or the substitute you show), and run it lengthways along a straight edge clamped to the table, a few degrees off perpendicular. If that's clear as mud I can probably show what I mean in a short video.
Side wheeling for such a tiny cut and tiny amount of material removal should not be a problem.
Thanks Craig
No joke I was thinking the same bench grinder setup this morning
@@TomMakeHere What method do you use for sharpening the end of the broach? As a basic circular grind wouldn't work well due to the series of flats and peaks inherent to a hexagon. Unless of course, it's okay for the cutting face of the broach to not be perfectly flat all the way around? I hope you're understanding what I'm getting at? Meaning that a consistent circular grind to hollow the face wouldn't reach the peaks of the hexagon without grinding out so far as to cause the straight edges of the face to be more recessed than the peaks.
The only way I can see to avoid this result, or at least keep it to a minimum, would be (after grinding a concentric, undersized hollow to the face) to carefully freehand grind the rest of the hollow out to the peaks.
But again, if it's not necessary for the cutting face of the broach to be perfectly flat around it's perimeter, then I have nothing to be concerned about.
Thanks Tom
@@smallblockchevy1022 the sides do become concave. This tool works on the 6 tips only, the pilot hole needs to be at least as big as the across flats measurement
I like how you think, and for sharing ideas like this for those of us without surface grinders. A rotary broach tool would be cool some day, but shop time seems to be mostly projects for work lately . . .
So long as you keep the workshop busy one way or the other!
Great video, a good way to encourage beginners and remind people of the options available with a bit of lateral thinking.
Absolutely! So many people talk themselves out of projects because they don't have
Experiment, and give it a go!
Thanks for the sharpening options. You have simple and at the same time very effective devices!
Thank you
Great video, well done and interesting. Thank you for all the tips along the way.
Glad it was helpful!
Thanks for watching
I loved the detail. Thank you
Yes I am trying to find a good balance between keeping projects moving and delivering information
Thanks for watching
great vid Tom, sick of seeing people comment that you need expensive gear to do the job you only need the drive and you'll find a way
That's right! Guess I'm selling my surface grinder now :)
@@TomMakeHere you need my delivery address?
I'll send it the same way Ca Lem is sending his machinery to me 🤣
@@TomMakeHere fite me! 😂
I like your suggestions here. I have both a Surface Grinder, and a Tool and Cutter Grinder, but you have offered good suggestions for those who do not.
Cheers! I was actually surprised at how well the other machine tools performed. I thought they would be way too slow to be really effective
It's nice to be proven wrong sometimes!
TommyGun Machining My grinding machines give me the creeps. They spin so fast, if something goes wrong it’s generally catastrophic. The methods you shared seem much more approachable. I was fortunate get one machine for free, and the other very cheap. Cheers to you, and thank you again for sharing.
Tom, when I get a bit of shed time I am going to try grinding some broaches using one of the cheap cup grinding wheels from the chairman over at candy rock mountain. I will hold the 10mm HSS in a collet block up against a stop then tilt the head on the mill to 1.5° (using a digital angle gauge) and with luck grind the broach. Rotating the collet block to grind each facet and with luck Robert is your father's brother.
Very useful tips Tom, thanks for sharing.
Regards John.
Glad it was helpful!
Great video Tommy, thank you
Thanks Matty 😁
Hi Tom,
I very much enjoyed this video... Lots of good approaches.
Take care
Paul,,
Glad you enjoyed it
Great information Tom,thanks for sharing.
Cheers
No worries
thanks for watching
liked your video, and subscribed. especially liked what you said about covering the ways.
Awesome, thank you
Yeah I'm not keen on lapping my ways with grinding grit
Maybe this video left you feeling like you really wish you had the machining abilities of this fellow...well you should check out the cinematic version, it will be leaving you jealous of his artistic and video production talents also.
Good stuff!
Thanks!
very good video..thanks for your time
Cheers,
Thanks for watching
Muito bom seu projeto, parabéns pelo trabalho amigo.
Obrigado!
Hi Tom, just wondering if there are plans available for the rotary broach? ;) Great video with excellent tips!
Wink, wink. Nudge, nudge. So subtle 😁
Thanks for watching
I was actually thinking about making a rotary broach for the #tmc2020, but settled on something a little simpler 😊. I've been doing ok (mostly) just freehand grinding most of my tools, but getting into small drills or key/groove cutters it's quite difficult to get it right and quality often leaves something to be desired. So at some point I'll have to address this issue. Maybe #tmc2021 🤣. Thanks for the share! Cheers!
Go for it! It's actually more straight forward than I expected to build
I won't tell you what I did to make my first keyways lol. (hint: it involves a boring bar and a hammer!!)
Some great ideas there! A very helpful video. For a limited use broach I think I'd be tempted to mill the broach in 01 tool steel, harden and temper, and finally stone the sides of the broach, a small fixture could be made to assist keeping the angle correct when stoning. Just another alternative though I can appreciate the life of an 01 broach will be limited, Unless I'm missing something?
absolutely. I'm sure it would work
I've not felt the tip after broaching, but I don't think it would get very hot either. So no risk of loosing temper, just wear of the edges
O1 is quite a capable steel, I've used it for punch tooling on automotive steel (HSLA), D2 is better, but unless you plan to use it in high production it will be fine. Hardening and tempering for this application will need some care, ref high hardness on the cutting edge, and strength behind. Hope this helps.
Outstanding series, Tom, now I can't use not having a surface grinder as an excuse to not make a rotary broach, I will be purchasing your plans.
Good luck on the boring table for your Hercus, I've been after the extended cross slide for my 260ATM, I'm thinking of machining my own up, I can't find any cast iron the right size, so was going to grab some 4140 from Josh, at Tyne Valley;).
Thanks mate,
Scott.
p.s. if you ever need somebody to babysit your surface grinder.....:)
I got a different one-off casting made up by Callington Cast Iron. Noone else seemed interested in a one time casting
It was a simple dovetail for my mill, and they were happy to do the simple pattern too
@@TomMakeHere Good one, are they local?
@@smacknives754 South Australia I believe. They were pretty much the only place in Aus that would do a single casting at a reasonable price
Man, I sure wish he had plans available. :)
😁
I wanted to clarify because people kept missing the fact that I had them available. I thought I'd make it very clear 😂
@@TomMakeHere I know, I was just teasing. I plan to buy them when I get paid again.
👍
😁
why not use grub screw to hold cutter in block instead of moving screw handle when turning block
The block came with a sharpening kit I bought.
Craig successfully shows a simple method in a block with a grub screw here: ua-cam.com/video/h42Yw2SH_7s/v-deo.html
I too bought your plans and the details regarding the bearings are great but I didn't see any reference to a materials list especially with regard to the broach tooling used.
Roger that. I will update the listing today.
FYI for anyone wondering the broaches are 10 mm diameter HSS with an overall length of 30 mm. That being said, you can ream to whatever diameter you wish.
@@TomMakeHere And which of the Tyne Valley listings might that correlate to (since it doesn't have 10mm HSS) the 4140 perhaps?
@Peter MacDonald Only just saw this message sorry, they stock 4140, tool steels etc. But not HSS to my knowledge
Você foi incrível, adorei seu projeto , poderia me enviar os desenhos
Gostaria de receber o projeto do Rotary Broach
Thanks for watching! I have plans available here: www.etsy.com/au/shop/TommyGMachining?ref=simple-shop-header-name&listing_id=831959563
I am also planning on making the full tool to sell early next year
Eu não acho pra compra no Brasil e quando acho alguma coisa e muito caro de mais
8:01 Good use to ebay xD
I have many holes in my tooling, I am gradually filling them. I focus on tools that expand capabilities first