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Replacing a Lathe Chuck
- Thread starter David2011
- Start date
Ahhh, I see. How cool is that
- Joined
- Dec 9, 2021
- Messages
- 738
I didn't explain it clearly. I was talking about the difference in depth of the counterbore in the back of the chuck vs. the length of the protrusion of the back plate that the adjusting screws bear against, not the difference in diameter of the counterbore and the diameter of the protrusion. My point is that it is better to have a gap than to risk the chuck hitting the protrusion before the mounting face of the chuck meets the back plate.
You did a great job of discussing the range of adjustment in the later post. I've never run out of adjustment with my Buck 6" 3- and 6- jaws, nor have I had any noticeable vibration. I assume that the offset has been too small to show up as vibration.
This week the CME adjustable structure 6” 3 jaw chuck and a suitable 8” D1-4 back plate arrived. The back plate has plenty of metal to cut down to fit the chuck and it’s thick enough without adding a spacer. I got back onto degreasing the lathe in preparation for paint. The degreasing was almost finished when other things diverted my attention for the last two weeks so there’s not much left. The outer sides and fronts of the base and the front of the sheet metal between the base pedestals are all that’s left. Saturday one of the RC clubs to which I belong is having an event so I probably won’t get back to degreasing and painting until Sunday.
Hoping that painting will go fairly quickly and I can move the lathe into its place on Sunday or Monday. I’ll sand all surfaces that haven’t already been sanded with a palm sander and wipe down everything with mineral spirits before applying paint.
At this point there are 3 back plates to machine; one each for the 5C, ER40 and 6” 3 jaw chucks. I didn’t want to start making chips on a very clean lathe until the paint was on and cured.
Hoping that painting will go fairly quickly and I can move the lathe into its place on Sunday or Monday. I’ll sand all surfaces that haven’t already been sanded with a palm sander and wipe down everything with mineral spirits before applying paint.
At this point there are 3 back plates to machine; one each for the 5C, ER40 and 6” 3 jaw chucks. I didn’t want to start making chips on a very clean lathe until the paint was on and cured.
Starting to think about getting an 8" 4 jaw chuck. My shoulders aren't as good as they used to be so weight is a concern. Is there any disadvantage to using a direct mount chuck compared to a plain back with a back plate?
The above mentioned 6" 3 jaw and back plate is close to 40 pounds. That's about my upper comfort limit for handling things at chest height. Beyond that I would consider a small shop built crane mounted to the lathe. A Shars 8" 4 jaw direct D1-4 weighs about 31 pounds. The plain back chuck with a back plate is about 48 pounds; quite a bit heavier and I'm only getting older.
The above mentioned 6" 3 jaw and back plate is close to 40 pounds. That's about my upper comfort limit for handling things at chest height. Beyond that I would consider a small shop built crane mounted to the lathe. A Shars 8" 4 jaw direct D1-4 weighs about 31 pounds. The plain back chuck with a back plate is about 48 pounds; quite a bit heavier and I'm only getting older.
- Joined
- Dec 24, 2020
- Messages
- 1,208
I don't think you give up much, if anything, when you're talking about a 4J independent chuck that's direct mount. After all, you're going to zero it out with an indicator each time, so any little error from the mounting setup will get adjusted away.
The only thing I'd suggest would be to mention that more often than not, buying from Shars directly usually costs more than buying from them via eBay. It looks like it's about $20 cheaper going through eBay.
8" D1-4 4 Jaw Independent Lathe Chuck
Shars 8" 4 Jaw Independent Lathe Chuck D1-4 TIR Runout Certificate R[ | eBay
Both side of jaw teeth and guides are ground and hardened to HRC 58-62. 7/16" Self-Ejecting Lathe Chuck Key. Internal Jaw Chuck Thickness 2.963. Semi-steel chuck body made from high quality cast iron.
www.ebay.com
Right. I've been shopping for a while. The Shars eBay outlet is usually but not always the best price for Shars items. Going through Shars direct is about $246 compared to $223 through their Discount Machine Shop eBay outlet. The worst price is through Amazon. The price is the same as eBay but Amazon shipping is over $70.
- Joined
- Jan 23, 2013
- Messages
- 124
I bought this one
Getting the backing plate machined was a huge pain in the ass because I couldnt machine it in place without turning it backwards first because my spindle nose was longer than the back plate.
The chuck is capable of better than .003 runout as advertised.
I ended up using some set screws to turn it into a set true chuck
6" 3 Jaw Self Centering Scroll Lathe Chucks 2 Piece Jaws With 2-1/4-8" Fully Machined Threaded Back Plate
Getting the backing plate machined was a huge pain in the ass because I couldnt machine it in place without turning it backwards first because my spindle nose was longer than the back plate.
The chuck is capable of better than .003 runout as advertised.
I ended up using some set screws to turn it into a set true chuck
- Joined
- Dec 23, 2012
- Messages
- 834
Did you grind the chuck jaws.
This something needed to be done ever few years in some shops.
The chuck jaws will wear little more on one side and you need to fix the problem
I only replace a chuck if scroll bearing is worn
Dave
I just noticed that Amazon has changed their shipping charge from $70 to $16.37. Unfortunately, it's too late for me to take advantage. To refresh, this is the chuck I ordered.
https://cme-tools.com/products/6?_pos=3&_sid=0f33368b9&_ss=r&variant=35553071116
The backplate I ordered was from Shars.
I was trying to get the 13" Victor completely repainted and a backsplash built before I started using it but the 11" Grizzly that's been waiting on a part since January finally wore to the point that I can't use it until the replacement part arrives. According to Grizzly e-mails it should arrive at Grizzly this week and to me a few days later. I really needed to get some parts finished, though so I started removing metal from the Shars backplate to reduce its OD from 8" to 6.582" and the registration boss had to be reduced from 4.75" to about 3.15". The 6" CME is oversized so a true 6" backplate is too small.
Aside from having to remove a lot of cast iron, cutting down the registration boss diameter went into the mounting studs a little way. There's enough uncut thread that I don't think it will be a problem. The people at CME told me that there is a backplate for this chuck; they just don't have any.
Last night I got the chuck mounted to the backplate and am please at the ability to dial out runout. I moved the piece I was working on when the Grizzly gave out into the Victor and was able to dial it in to the point that I couldn't see any movement of the dial indicator needle. I had seen that in videos but it's my first time to experience it.
https://cme-tools.com/products/6?_pos=3&_sid=0f33368b9&_ss=r&variant=35553071116
The backplate I ordered was from Shars.
I was trying to get the 13" Victor completely repainted and a backsplash built before I started using it but the 11" Grizzly that's been waiting on a part since January finally wore to the point that I can't use it until the replacement part arrives. According to Grizzly e-mails it should arrive at Grizzly this week and to me a few days later. I really needed to get some parts finished, though so I started removing metal from the Shars backplate to reduce its OD from 8" to 6.582" and the registration boss had to be reduced from 4.75" to about 3.15". The 6" CME is oversized so a true 6" backplate is too small.
Aside from having to remove a lot of cast iron, cutting down the registration boss diameter went into the mounting studs a little way. There's enough uncut thread that I don't think it will be a problem. The people at CME told me that there is a backplate for this chuck; they just don't have any.
Last night I got the chuck mounted to the backplate and am please at the ability to dial out runout. I moved the piece I was working on when the Grizzly gave out into the Victor and was able to dial it in to the point that I couldn't see any movement of the dial indicator needle. I had seen that in videos but it's my first time to experience it.
The jaws of the old chuck are very loose in the body of the chuck. Grinding wouldn't have fixed the problem.