Disassembling and Cleaning a Three Jaw Lathe Chuck and Machining a New Back Plate
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- Опубліковано 29 тра 2024
- This video shows how I went about tearing down a Rohm 3 jaw chuck for cleaning and reassembly. Then I machine a new back plate for this chuck to fit the L0 spindle on my Rivett 1020S metal lathe.
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Keith... Don't grind the jaws. You have so many other options.
1) Re-index the chuck on mounting plate.
2) Machine down that tapper on back plate instead of relying on the stress the bolts are placing in the pulling of the plate itself.
3) Don't grind the jaws.
4) Thank you for the video.
He will do whatever requires the least thought and the least opportunity to reflect on his own actions.
Nice job on machining a backing plate. One suggestion on the reassembly of the chuck; if when you install the three pinions, set them so the square drive for the "T" handle are all in alignment. That way when you set a piece in the chuck the "T" handle will be aligned with all three pinions as you turn the chuck to tighten the work piece. It made a noticeable difference in the ease of tightening on my three jaw chuck. Just a thought, :-)
I have never thought about that! So annoying when doing 30 or 40 of a part and every time you take a part out of the chuck the key is in a different position depending on which pinion ends up closest to the top once rotation stops. I'm gonna try that out the next time I clean out my Bison 10". Thanks!
Glad I could help. I use all three pinions to tighten a part in my three jaw every time so I get the best possible security of that part. I just feel better when I do it.
A modification that works really well is to relieve the radial register that the chuck sits on. Inherently, scroll chucks always pull the jaws to the side since there has to be clearance for the scroll to turn inside the body. I learnt the trick from Stefan Goteswinter. Make your chuck float and tap it into center with a copper hammer. I've done it myself too and it works really well, as long as you don't forget to tighten the chuck back to the backplate!
Just like dialing in a 4-jaw, just with a hammer.
I have done that floating thing for almost 15 years and it worked well, but only in a lathe running at 630 RPM maximum. Recently I bought a better used lathe that reaches 2000 RPM and I don't know if doing the same will get good results, cause that RPM difference.
h0useisafeeling I’ve ran a steel body 3 jaw chuck floated at 2000 rpm with parts about 25mm in diameter. Nothing creeped or sounded bad. In my view, it’s still the same bolts holding your chuck on.
Ok I'll o look up
I did just this with a CC 5C collet chuck. 20 thou undersized register, fasten the 3 screws just over finger tight, chuck a 1" bar in the collet and indicate on the bar. Then tap the chuck body sideways until you achieve minimum runout. I achieved zero on a regular 0.001" indicator. Tighten all the screws and recheck. All ok.
@@ronwilken5219 yep, still using this method here too. It’s very nice to have the option to dial in your chuck when it’s needed.
Some day I'll have enough tooling that I can lay in bed and remember I have a NOS Rohm chuck sitting on the shelf! ----Aaron
"I'm gonna let this cool down". Translation: "It's lunch time and I'm hungry."
You could also machine the taper on the backplate a bit more and then indicate the chuck to run true, just like Stefan Gotteswinter. They say, if you can't make something absolutely precise, make it adjustable.
I'd be inclined to re-index the chuck on the mounting plate before grinding the jaws, also there's actually only .002 run out that needs to be located, that is it could be axial or radial, you may want to indicate the mounting plate just to rule out variations.
That's not to mention that grinding the one face of the jaws means that all the other jaw faces are left in error.
If it's reasonable to assume that the chuck itself is internally consistent, there's no good reason to make it inconsistent to compensate for an external error.
If you grind the jaws, remember you will also have all the steps on the jaws and when you turn them around you will have even more runout. Better to get the chuck to run as true as possible before resorting to grinding two piece jaw chucks.
Rambozo Clown I was thinking same thing. To me the gap he tightened down the chuck to the back plate. He cranked on one side without incrementally tightening them. It doesn’t take much to introduce 4 thou runout
Keith, you should access the runout on the backplate (repeatability with the lathe) and probably machine down that taper a little. Sucking it down with bolts is just introducing stress is the setup which is never a good thing for precision. Keep the videos coming.
Everyone enjoys watching someone who's life seems to be going better than our own.
That German Röhm chuck is some high-end stuff.Definitely worth the effort you put in here. Good Job Mr. Rucker
Keith using a modern import chuck?! What's the world coming to?
A 3 jaw buck chuck will be my second choice. Being 100 percent machined , they are balanced.
My first choice is always a 4 jaw independent.
Did you try reclocking/remounting the chuck to the backplate in the other two possible mounting positions to see if the runout improved?
@@anonymic79 Just to eliminate possible causes of the runout before he grinds the jaws, perhaps he missed a small chip or something during assembly of the back plate or mounting it to the lathe, if the runout is consistent and the back plate is true, then you know for sure it's the chuck and you can go to a more drastic measure to remove the runout.
J-man72 b I’m curious if the body of the chuck is running true.
Perhaps that is revealed in a later video. (I’m living in the future so I can look back :)
You should blame the run-out on the grease you used..... like Dale did recently lol!! 😁😉
Like others have said, I'd avoid grinding the jaws unless none of the other suggestions haven't made any improvement. I'd work on that register taper first. It's so close you could probably polish off enough to get the chuck to seat cleanly on the back plate without having the mounting screws having to pull it into place and stressing the chuck body...it doesn't take much to have it pull 0.002" (0.05mm) when measured 4" (125mm) away from the register.
Cheers from NC/USA
A lathe really is about the only machine that can rebuild itself with itself. They are so cool.
nope it cant machine its own bedways, though it could machine one smaller than itself
@@jusb1066 what if you could build a 90° milling attachment driven off the head stock? Possible?
A great job on mounting a three jaw chuck ‘for thou’! (Thanks for another informative detailed video.)
I would re drill the chuck it jumped when you transferred the holes and when you were tapping the plate it lifted in the vice .
i agree
Wow a lot of comments disapproving of the way you work. I am not sure but I believe Abom79 realigned his 6 jaw chuck to get it running truer. It might be worth a look to see how Adam did it. I am not a machinist so its all interesting.
Eric McRae look on it as constructive criticism I don't think any malice intended by anyone.
That new camera lens is really interested in what you are doing.
It keeps moving in for a closer look.
Cheers,
Keith you probably should have drill and taped 3 more holes in the mounting plate so you could put a bolt in and push the chuck off the plate if you wanted to, going to be a tight fit on that taper, just a suggestion. As always a great video.
I absolutely love being able to dial in my Bison 3 jaw. I haven't checked it since making the new spindle adapter, but as it's due for the same kind of treatment you've given this one, there isn't much point in doing that now. It's beginning to feel like its getting a little dry inside, so it's time to take it completely apart and go through it. I found an old tube of lubriplate in my utility trailer (barely readable, but the contents seem to be good) and I'm inclined to try that in the enclosed areas where the scroll works are. 98 lbs+ of chuck wrestling awaits, I'll be glad of that chain hoist by the time it's done.
I worked at the Boeing plant you spoke of. When I started it was Boeing Ga. Inc the it was sold to Lucas Variety then it was sold to TRW Aerospace. I worked for three companies in the same building. After that it was bought by a private co. In the mean time Boeing bought out Mcdonnel Douglas which was just down the road. That facility became Boeing again and I worked there too. Boeing finally closed and moved out of Macon. For many years Boeing had a presence in Macon and I don't understand to this day why they left. Sometimes corporations make stupid decisions because there was always an experienced labor pool because of the air force base. I paid a lot of bills while I worked there....... Just think I may have used that chuck.
another state offered them a tax break, or something
Question: the lathe is capable of high enough speeds that a steel bodied chuck is required. Why then is cast iron ok for the back plate? Less machined features where it could unzip? What about possible voids is the casting of the backplate? Not criticising - just want to know. 🤔🤓
It's always a pleasure to watch your work Keith. Thanks.
THANK YOU...for sharing. Enjoyed.
That shavings from facing looks amazing :)
Love the Famco lurking in the background.
Nice share, Lance & Patrick.
Nicely done.
Thanks.
Hi Keith, I haven't read all the comments but one I'd like to make is that the inner plate of the chuck has a large hole drilled in it I'm assuming to balance it. If that's so then the orientation of that plate to the rest of the chuck would be critical. I didn't see you punch or make any witness mark between the two before you dismantled it. If you did, please ignore this comment. If you didn't you might want to try the plate in the other two possible positions. You might find it balances better elsewhere. I did see some comments about runout. This might also help correct that. Rhom generally have a good reputation so I find it hard to believe a Rhom chuck almost new would have a bad runout without a good reason.
Looks good. I've turned backplates for some older worn chucks. 4 thou woud've been amazing for those old guys!! Thanks for the promise on showing the fix.
Maybe I wasn't paying attention, but I don't recall seeing the final .013 taken off that backplate. Wondering about some runout after the cool down... could surely affect the indicated runout of the chuck.
Love watching your videos Keith I learned so much ! Keep up the good work happy Memorial Day 👍👍🇺🇸🤠
Thanks for the lesson in matching a chuck to a lathe. Happy birthday!
Hi Keith. Thanks, reassuring - I have to make one. Presumably the run out is in the 'new' chuck itself. Even with an error on the spindle side of the backplate the backplate taper you turned for the chuck must be concentric, geometrically it can't be anything else. It would be educational if you could put an indicator on it to show that. If feeling totally crazy, mount 'new' chuck reversed on a substantial short arbor turned in an existing chuck - so it has to be concentric - and check run out on 'new' chuck rear internal taper. Doubt that I'd bother! It would assume that the chuck jaws were all parallel, and that the arbor was totally rigid - so grinding in place sounds like the right solution. BobUK.
another excellent video, thank you sir.
I have a Buck 3 jaw chuck on the American Pacemaker (L-3 taper) called "adjust true" that can be dialed in like a 4 jaw. I also made one for for my 20 in Monarch copying that principal. Much larger chucks, but They work great. looking at yours I think the same thing can be accomplished on a smaller scale by loosening up the center taper and "half tapping" 4 holes spaced 90 degrees in the crack between the back plate and chuck and installing flat bottom set screws, then, replace the mounting bolts with a more hefty fine thread bolt to increase clamping force. Doodle the set screws or tap with a hammer then tighten the mounting bolts and it's 00 with any jaws.
Perfect timing. I have a six jaw that needs a backing plate. I had a general idea of how to do it, but now it’s crystal clear how to approach the job. Thanks for sharing your expertise! Brilliant!
Keith Fenner did a series of videos on making a new backing plate a few years ago if you want to go back and take a look. I think he showed the entire process of making the thread to match the spindle, the inner taper, machining the keyway and then fitting to the chuck. I'm not trying to negate Keith Rucker's video at all, just passing on the info for the curious minded.
thanks for a good job keith. Cutting that final cut was nerve wracking on the taper.
Curious what the runout on the chuck is as well as deflection. I would also like to know what the total runout error was on the original backplate.
My goal would be to ensure spindle, then backplate, then chuck and THEN jaws were true before I machined anything else.
I had a lens that zoomed in on its own too if it was pointing downwards but it had a lock lever if I remember correctly. This video made me go clean my 4 jaw too... It's a bit rusty and needs some grease. Thanks for the inspiration. :)
Very interesting thanks for sharing.
Learned a lot
A Rohm, Nice quality!
The lens is zooming in by gravity lol. Had that happen many times. Lock the preferred zoom level with a piece of tape, or setup the camera on a steeper angle.
Good video Sir !!
All the best to you and yours.
I know this will sound goofy and I'll likely get passed over but its worth a shot talking down the hallway. The scroll on a chuck should be assembled with moly high pressure grease, nothing else. Due to the sliding surfaces and the intense force that the scroll imparts on the jaw backs, non-moly greases can actually cause sticking and the jaws not to provide uniform pressure. Its been seen many times before and I have seen it myself as well. The teflon grease from that can might cause a loss of over 10 thousandths in runout in a chuck due to improper lubrication causing sticking.
I liked this video. I machined a back plate on a similar chuck, (I’m no machinists), followed all the same steps, and still ended up with the same run out. I think my problem was is that I think I machined the boss just slightly under size, in the fact that if you can hand fit the plate tight against the chuck, then it is too loose. I think that you should have to “tap” it in or pull it together with the bolts, then “tap” it apart. Once again, I’m no machinist! Thanks for the video, hope to see you at the summer bash! Thanks, JB San Diego.😀
This is the kind of job you don't want to do, but if you do it right, it will last a 100 years with care. Thanks!
For Keith this is brand new the chuck is less than 30 years old
You tube loves regrinding chuck jaws ... I recommend going slow and investigating where the run out is coming from ...in particular check how well the jaws set in their guides and make sure the teeth on jaws are clean and burr free... and as in a previous comment check all three mounting positions on the backplate... and check for both axial and radial runout... a nearly new rohm chuck should not need it’s Jaws ground ... but as last resort grind them
I remember that when you put it away
Keith
I am surprised that you did not machine that back plate to 0.5mm of finish size . Take it of the lathe spray it down with Anti rust put it in a poly bag then leave it outside of the workshop to age for a while. Then finish it to size ,looked like CI to me from the chips ,internal stresses build up
I have done a few in the past and all have moved over time and had to be trued up
great video as is your normal practice ,and you have the courage to display warts and all
I'm surprised that you rely that much on dial calipers for measurements. They're good for reference but will never be as accurate as a micrometer. I would also try clocking the chuck different as others have said first to check run-out. When you used the transfer punch the whole thing jumped on the table you where using.
yeah, probably better to drill and tap one hole, assemble the backplate to the chuck, then transfer punch the other holes while the assembly is clamped.
@@chris0tube I saw the chuck bouncing away from the plate as he punched the transfer punch
@@chris0tube
Can you read this? I'm beginning to wonder if I've been stopped from commenting.
@@chris0tube
Thanks and yes you are here too.
Start testing from the power head out, instead of from the chuck jaws in. Foundation first.
This job was one of my first thing I made on my lathe. Found out that HSS steel is not up to the job of cutting cast iron. Lucky that i found in my fly cutter i had HSS Co 8%.
Nice job Keith. I learned a lot:)
I agree with trying a different index first, I’d be inclined to turn the register a bit looser and see if I could move the chuck around on the backplate then tighten the screws. .002 off the backplate then a dead blow hammer to indicate the chuck in.
Hi Keith, many thanks for putting so much time and thought into your videos. A big shout out as I only recently realised that you are doing this as a one person operation in the main and that vintage heavy engineering is certainly heavy.
I'm just seeing this one some 6months after the event and had some thoughts as to why the ROHM chuck was uncentered by 4 or so thou" after relubing it . I'd noticed that the rear inner cover looked like it had a balancing drilling in it as do most modern high precision, high speed machinery parts these days. Perhaps repositioning the rear cover through 120 or 240 degrees may improve the centring even if dynamic balancing isn't a criterion for the tough lathe that it's fitted to? I appreciate that this is coming late to the party as your subsequent video sorts out the out of roundness question. BTW the tapered recess aka DIN taper, in the rear of the chuck sounds like a good solid way to mount a chuck repeatably especially if your headstock spindle has the same .
Keep up the good work. I'm always learning.
This gives new meaning to "Cast iron fountain".
Thanks
25:33 If it were me and knowing my luck I'd probably drill and tap one of them first since I'd be paranoid that the chuck might shift a little between center punching the three holes. Either that would happen or my drill would wonder on the first hole and then my next hole wouldn't be 120deg from the one I finished. I'm sure you made it work perfectly considering you're a much better machinist :)
@17:51 I felt like *I* should be wearing goggles from that chip fountain!
I would indicate the taper and the backplate first, then the outer diameter of the chuck to verify any run out in those components first. Rhom is first class stuff so I would avoid taking the grinder too it until last resort.
Got to agree with the large number of commenters that grinding should be the last resort. Take their advice, it’ll make an interesting video. Regards
Im not one to complain, but i think you should think about relocating your lapel microphone, or using something different, the breathing into the microphone can be a bit much for me sometimes lol
The audio was not perfect, but an order of magnitude better than far too many YT channels.
The first thing I would do if I found the accuracy results at the end of the video is to indicate the spindle taper at both ends for run out, then the working face of the mounted chuck near the outer diameter for run out, then test the outer diameter of the chuck both near the face and near the back plate, writing any deviations on the chuck as you go, to build a three dimensional mental view of the errors, if any. With the mounting of the two tapers like a D or A series chuck, it is possible to have an incorrect fit that allows the chuck to tip on it's mounting in a conical fashion, chuck tipped off the center line of the lathe, wallowing like a swash plate as it rotates. If that is all good, check the condition and fits of the 6 jaw parts carefully for any issues like burrs or poor fit. If all of those are correct, THEN grind the jaws.
I always hated running tapers at work with no standards to help us, you made that look easy.
@@anonymic79 did I say he used a standard? We didn't even have what the part we were making fit in. Why you felt the need to chime in when I was giving him a compliment I just don't understand.
In case the runout is repeatable, You might get rid of it by simply making the backplate/chuck index a "loose" fit. Something like +/- 4 "thou" wiggle room. After that just mount the chuk on the plate and into the lathe without excessively tightening it. Then just bump it to zero runout. Aften that tighten the bolts and there You are.
You can, of course, grind the jaws but at least in my book that only works for a given workpiece diameter if the rest of the chuck has a runout.
Now he will have to buy another lathe to fit the old back plate.
Please, don't give him any such encouragement.
Keith.
Only one problem with Grinding The Jaws Internally if in future you want to use it to hold anything Larger by The Bore to machine, The other holding Lugs will still be out 0.004 which You mentioned was unacceptable so in reality you will also have to grind them .
It's always nice to have an accurate 3 & 6 Self centering Jaw & I'm astonished when I see Many People using Very nice 3 & 6 Jaw Chucks to hold Rough Forged Stock The practice I was taught was if it wasn't Bright Rolled Ground, or Turned Metal use a 4 Jaw & I worked For The Australian Government where everything we had was the best available.
I realise your'e not Chasing 0.0001s however On all our Browne & Sharpe Cylindrical Grinders where I Did my Apprenticeship & worked for many years as A Toolmaker we had a setup where we had a Back Plate with a Boss/ Register Screwed to The Machine Spindle to which we could fix with Scews 3 & 4 Jaw Chucks onto a Boss with 4 set Screws,each at 90 Degrees so we could chuck The part & adjust it as we were always working with very Fine tolerances of 0.0002 Max .
I still remember Cylindrical Grinding a 40 Inch x1.5 Inch 308 Cal Proof Barrel we were making for testing Ammo & New Powder Loads for The Australian Army on a Old 2nd World War Cylindo to 0.0001 because it had to have 4 Inch Bosses Shrunk onto it so it wouldn't explode as The Newer Modern more accurate machines couldn't handle The Length
Great job! Can't wait to see the grinding of the Jaws.
coming your assistant 😁
great video!
I was wondering if I can use the imperial transfer punch in the metric holes of my 4 jaw independent 125mm chuck. you proved it will work just fine.
I was already thinking to turn the mini shafts to the hole diameter, cut them slightly proud of the hole depth, and then taper the tips to look like a pencil. and then I might have to harden the tips, (or they would work at least once without hardening) then put them all at once in all 4 mounting holes, align the chuck with the back plate, and make the holes centers.
I have never in my 45 years of makin chips used a hammer on a lathe chuck
Keith you could get the tang of a file or the skip of your bunnet in the 4 thou space ...
I find that it is easier to mount a chuck on an L taper by first rotating the spindle so the key is at the top. In this position it is also easier to see that there are no chips at the base of the key.
no need for grinding the jaws if the chuck is in a reasonable state, röhm chucks this size actually could maintain below a tho runout if mounted properly.
your problem here def is the mount on the backplate, it looks like the chuck was delivered with Nr.5 DIN 55027 spindle hub mounting plate. thing is with those the diameter and taper are very precise with quite unusual numbers, like 82.575 mm mean diameter and a taper of 7 degrees 7 minutes 30 seconds and require a very precise amount of play before tightening on spindle hub along with proper fit of the taper, in like 0.02 to 0.05 mm in axial direction in order to maintain proper preload without excessive deflection of both chuck and spindle hub.
imo it's pointless to try to machine the backplate to such precision on the taper, on a lathe anyway, so what you could do instead is to shorten the taper plate of the chuck until the main mounting diameter of the chuck becomes visible (about 2 to 3 mm is plenty, the diameter is 160H6 for a 200 mm chuck like this one) and machine a journal on the backplate with either close to zero play or a very light tight fit. the runout (4 tho is ridiculous) should decrease plenty if the chuck is okay, so have a shot.
cheers.
Some people go to bed perchance to dream of fair maidens or whatever. Keith dreams of lathes and other wonderful pieces of machinery. 😂👍
Matching taper angles and calculating stock removal to achieve a gage line are classic apprentice school problems. Your taper half angle is 7 degrees. The shoulder gap can be measured several ways. The amount of diameter reduction to close the gap is a simple trig problem where the infeed setting for a given gap reduction is: radial infeed equals gap opening times the TAN of the taper half angle. The gap opening is a parallel plane measurement difficult to determine on the machine. This may taken using matched feeler stacks on either side with the chuck pushed on the roughed taper by a light thrust of the tailstock quill. It may be more simply approximated by deliberately angling the chuck to bump flange to chuck back and halving the opening of the wedge shaped space thus created.
'Taking off a little at a time," "sneaking up on it," "try it and see" are wasteful techniques in terms of time and potential for spoilage. Simple shop math works and saves you time.
BTW, the fit you are seeking in mounting the chuck to the backplate is a "draw fit," that is, the attaching bolts are intended to pull the chuck onto its taper with a small interference specified in USAS B5.9 - 1957. The taper half angle is 7 degrees 7 1/2 minutes. The spindle pilot taper is measured to a theoretical intersection dimension as is the tapered recess in the chuck. This intersection diameter is intended to have a 0.0003" to 0013" interference. Working the math, the minimum draw should be interferance / TAN of the taper half angle or 0.0024.
This makes a nice little problem to calculate size over pins or balls, working out a reliable method of measurement, etc. But you have to be practical: you want to get that new chuck mounted and into service avoiding fancy metrology if at all possible. My approach was to cut the taper to attain the right amount of draw refining by dressing down the pilot taper or if I overshot, faced a couple thousandths off the flange.
Rohm inaccurate seems unlikely methinks. Mind id love to know quite how they do make such beautiful work, so accurate.
It would be interesting to see if the runout still was 0 at the backplate after you removed it and put it back on the machine.
A metric chuck should also have a metric taper. 7º= 0.1221730rad :-)
It mystifies me that Americans still stick with imperial. We moved to metric in the UK a good 50 years ago, and it took a minute to get used to it. The whole divide by ten thing as opposed to fractions. I assume you use a decimal system on machine slides for instance?
Keith, nice step by step instruction. I have a question. Initially you emphasised the need to have a steel chuck because of the high speed capability of the lathe and the danger of a cast iron chuck at high rotational load exploding. Watching the video I noticed as you turned the back plate that it is likely made of cast iron. Would not this plate shattering be a danger as it is cast iron and has holes close to the periphery that may concentrate crack propagation and exacerbate the likely hood of fracture? Looking forward to hear your thoughts, Richard.
I'm curious to see what the runout on the body of the chuck would be.
I was also hoping to see that to.
May be nothing but that rear plate of the chuck not the part you machined had a balencing drilling and that plate was rage female register for your back plate . Was it dowelled to the chuck body to preserve the correct relationship , did you match mark it when you took it apart
I would try that in the three positions before you get a grinder near it
Stuart
Should have said that plate was the register plate for the chuck , and should have been put back in the same position
Thanks for the informative update cam. You have increased my knowledge
I was hoping to see a demo of the centre finding microscope you showed in the odds and ends. Maybe compare to your centre point. Have to agree with some others about the taper not fitting perfectly. Maybe remount the back plate and this time use a torque wrench to ensure the stresses are equal. Considering the speed of that lathe are you aware of an optical method to measure run out at speed?
I'd be inclined to lap and print that taper on the back plate before grinding the jaws. If the taper is still a touch proud it would cock the chuck over when you tightened it
Even with the .004" runout, I thought it was a cool project. Being a premium brand chuck I would look for better as well, but sadly .003-.004 isn't out of line for import equipment. Will be cool to see what methods you try, if you do try other stuff before grinding the jaws.
Machine that taper correctly to fit and yo may not be introducing that error by flexing the housing.
Nice job, How do you accurately get the 7 degree on the cross slide for the taper?
MAD Free Speak Aligning the marker EXACTLY with the 7° line would do the trick.
he could use a sine bar and be more accurate...
If a taper is that critical, there is no way I would rely on the degree lines on the cross slide
I've always wanted to know... What brand and type of drill bits are you using?? Thanks
Keith, you mentioned steel vs. cast iron. When machining the back plate, the chips were small. Could the back plate have been made from ductile iron? "Routine" gray cast iron would have produced powdery swarf and it's clear you were not dealing with that.
Keith, I noticed when you center punched the three holes for the back plate I didn't see you index the chuck body to the plate to realign the holes after drilling/tapping. Do you think some of the runout could be "cured" by reclocking the plate to the chuck?
Best wishes,
Eric
esoomreltna-I think you’re onto something with your comment. The back cover on the chuck had what looks like a drilled balancing spot on it.
29:58 Have you ever tried your hand to make an adjustable backing plate? I haven't seen exactly how the three-jaw chucks that have an adjustable four-jaw style backing plate work but I've wondered if could do it for any face mounting three-jaw chuck. Just something interesting to think about. Thanks for the amazing videos!
Nice work. Did you get the Chuck from an estate sale on Old Lundy Rd in Macon?
Why not just take 4 thou off the register so you can bump and retighten the bolts?
Jusb1066 known as a "bump-tru" chuck.
@@littleworkshopofhorrors2395 indeed and the build something channel made his chuck worse in his recent grinding video
Can the chuck be trued with a little sliding of the individual jaws?
The jaws don't seem to be radially indexed.
Not really. They are indexed. Fixed in their radial position.
see the big slot running across the jaws that stop them sliding in/out? 12:40
Your new lens is probably quite heavy, and zooming in under its own weight when pointing down :)
Zoom creep. Lenses with extendable barrels can be susceptible to it.
My thought exactly. He needs to find a thick, wide rubber band to straddle the zoom ring and lens barrel. Zooming will be a little more difficult, but the creep will be gone.
Interesting video though I'm curious about the face plate it looked like it was cast. If so and you didn't want a cast chuck why use a case face plate?
Cast iron is very brittle and chucks have porosity and a lot of holes cut in them for jaw slots, pinions, and bolts. Lots of holes in cast iron are places for cracks to start. A heavy chuck spinning at 1700 rippems is a bomb waiting to happen. Gets a lot worse the larger the chuck is because of centrifugal forces.