Fitting new D1-5 chuck adapter correctly

[mcdanlj]

I just bought my first new chuck (an ER40 collet chuck) for my lathe; all my previous chucks came with the lathe when I purchased it. This was a set of an ER40 chuck and a D1-5 back plate. I have no experience to know what to expect and would appreciate help.

I understand and expect that the registration face and boss on the adapter need to be finished on my lathe, and I'll get there.

However, the D1-5 taper on the back of the chuck adapter doesn't appear to be a tight fit. When I put the chuck adapter onto the nose, the back of the chuck plate registers against the end of the spindle, but that tiny little nose taper doesn't seem to touch, and I can wiggle the adapter slightly. I realized that I don't even know whether it is supposed to be able to move, but I don't understand how registration would be consistent without the nose taper fitting snug.

Should I expect to have to mount the adapter backwards in another chuck and skim cut the back face until the nose taper registers firmly, or is it OK for it to feel slightly loose until I tighten? I am not going to start cutting anything until I know that I'm supposed to, since un-cutting is famously difficult.

I would not be at all surprised if there is an existing thread covering this that I just didn't know how to search for, so a pointer to an existing thread, and possibly instruction in what search terms would helped me help myself, would be a great help. I'm just trying to bootstrap my knowledge here.

Thanks!

 

[epanzella]

My lathe is also D1-5 so I'm interested in this thread but unfortunately I haven't yet done what you're doing. I would suggest that you put a sharpie mark on the adaptor and lock it to the spindle while putting pressure on it in various directions checking for runout between each direction change. Maybe the taper doesn't get tight until you cinch the cams down. Bear in mind I'm just guessing here.

 

[mikey]

The key reference surface on a camlock spindle is the 7 deg, 7 minute, 30 second taper at the nose of the spindle. Any chuck that is put on the lathe should have a matching taper in back so you are absolutely right that the taper must make full contact. Some chucks or back plates touch the spindle face when tightened down; some do not. The ideal is that the taper seats fully and the back plate touches at the exact same instant but this doesn't always happen. The key, at least in my experience, is to have the taper solidly in contact.

Sometimes the taper on a new chuck or plate can be a bit finicky. Before fitting a new plate on my lathe, I take a piece of gray (very fine) Scotchbrite and go over the female taper in the plate. If any burrs are detected, I remove them. Then I wipe the spindle taper and female taper really clean with alcohol and then oil them both very lightly. Then I put the plate in place and, in stages, tighten the camlock studs. When I get the studs all locked down I check to see if the plate touches the spindle face; if it does, fine; if not, then it doesn't. This isn't that critical as long as the taper is locked. To check if the taper locked, loosen the camlock studs to see if the plate falls off. If it does, that's bad. If it takes a whack with your hand or a deadblow then that's good.

When you first try to tighten the camlock studs, go easy. If the taper in the plate is not machined well it can mar your spindle nose so tighten slowly and in stages to make sure the chuck is being pulled in evenly.

The other thing to watch for is that the camlock studs and the cleanliness of the threads they fit into in the plate are often not of the highest quality on asian import plates. Clean the threads with a brass brush and clean the studs. Most should have a line on the stud to line up with the back of the plate. If not, match the stick out with a chuck that you know works. This matters because you want them all pulling evenly.

Hope this helps. You got this, don't worry.

 

[mcdanlj]

I did in fact mark the nose taper and seat the adapter, and

• I had almost no transfer to the adapter from the nose
• When I loosen the camlock studs the adapter comes off the nose, so it is not locked to the taper.

Therefore, to the point of it being easier to cut than to un-cut, I need to return this set as defective; I can't make that taper smaller. Doesn't matter how accurate the taper is if it doesn't lock. Runout won't repeat.

Thank you for talking about going easy in any case! Yes, I tightened lightly in stages and checked for engagement before doing that again and attempting to set firmly. Also yes I did a lot of cleanup before putting any screws anywhere.

 

[mcdanlj]

Thought that I'd follow up: For my next try, I bought the Precision Matthews set, which I discovered existed about 5 minutes after purchasing the initial (defective) set from someone else. It came fully finished rather than semi-finished. The taper was smooth and set without apparent movement. After carefully tightening it, I tapped the set-tru-style collet into place on the adapter plate to about 1 tenth TIR. I indexed my 0 position with a punch. Releasing the cams did not release the chuck from the spindle nose; it took a light tap to release it from the nose. Re-installing it and tightening it returned it to the same 1 tenth TIR, so registration repeated. The threads on the collet nut on the PM set were smoother than the defective unit, so the nut turns more smoothly, too. Bonus!

(The seller of the first set promptly refunded everything including shipping and covered return shipping as well, so I don't want to name and shame them for a mistake. Problems happen. But I did want to call out that I'm happy with the PM set.)

@epanzella in case you are thinking seriously about this: https://www.precisionmatthews.com/shop/er-40-adjustable-collet-chuck-d1-5-mount/ was what I bought. They shipped immediately, arrived quickly, well packed. I had also previously bought their https://www.precisionmatthews.com/shop/26-pc-precision-metric-er-40-collet-set-1-26mm/ which it turns out actually goes all the way down to 0.5mm — not that I have a specific need for 0.5mm! For an imperial set I bought a 23-piece set rather than the PM 15-piece set. I wanted more sizes so that I can find close matches for arbitrary sizes of partially-finished work. I haven't tested the quality of any of the collets yet.

 

[epanzella]

Thanks,
McDan

 

[NC Rick]

The key reference surface on a camlock spindle is the 7 deg, 7 minute, 30 second taper at the nose of the spindle. Any chuck that is put on the lathe should have a matching taper in back so you are absolutely right that the taper must make full contact. Some chucks or back plates touch the spindle face when tightened down; some do not. The ideal is that the taper seats fully and the back plate touches at the exact same instant but this doesn't always happen. The key, at least in my experience, is to have the taper solidly in contact.

Sometimes the taper on a new chuck or plate can be a bit finicky. Before fitting a new plate on my lathe, I take a piece of gray (very fine) Scotchbrite and go over the female taper in the plate. If any burrs are detected, I remove them. Then I wipe the spindle taper and female taper really clean with alcohol and then oil them both very lightly. Then I put the plate in place and, in stages, tighten the camlock studs. When I get the studs all locked down I check to see if the plate touches the spindle face; if it does, fine; if not, then it doesn't. This isn't that critical as long as the taper is locked. To check if the taper locked, loosen the camlock studs to see if the plate falls off. If it does, that's bad. If it takes a whack with your hand or a deadblow then that's good.

When you first try to tighten the camlock studs, go easy. If the taper in the plate is not machined well it can mar your spindle nose so tighten slowly and in stages to make sure the chuck is being pulled in evenly.

The other thing to watch for is that the camlock studs and the cleanliness of the threads they fit into in the plate are often not of the highest quality on asian import plates. Clean the threads with a brass brush and clean the studs. Most should have a line on the stud to line up with the back of the plate. If not, match the stick out with a chuck that you know works. This matters because you want them all pulling evenly.

Hope this helps. You got this, don't worry.

That was one of the most helpful and informative posts I have read in a very long time. Thank you so much. I have had a lathe with a D1-6 chuck for over ten years, have several chucks and have fit a few back plates so have figured out much. I didn’t know those details and appreciate your knowledge and sharing.