3 Jaw D1-4 Chuck

[extropic]

in case you think I am a lone wolf making these claims, here's some corroboration I found in 2 minutes:

Lathe Spindle Nose Standards & Lathe Chuck Mounting Types

When replacing a lathe chuck on your machine, you need to choose the right direct mount chuck or adapter plate. More on lathe spindle nose standards here.

www.northlandtool.com

What's the proper fit for a D1-6 chuck to the spindle register?

This is a 17" lathe fitted with a 8"-D1-6 Bison chuck. When I mount the chuck it takes some finesse and tapping with a dead-blow hammer to fully seat it on the register..it's more than snug. Today I realized that run out is dependent on the sequence of tightening the cam locks..tightening them...

www.practicalmachinist.com

On the NTE site, I couldn't find one mention of the issue being discussed.
On the other reference, all I read was personal opinions. Not a single reference to a credible industry or manufacturers document that speaks to the issue.

I would appreciate a through description of the process you used to lap those chucks.

We have many members that have bought new lathes that are supplied with chucks and owners manuals. Are all those chucks tight against the spindle nose? Is there any mention in the owners manual for "properly" fitting a new chuck?

 

[Dabbler]

On the NTE site, I couldn't find one mention of the issue being discussed.

This is what you are looking for

To mount a chuck, the lathe operator inserts the pins into the spindle and rotates the cam, pulling the pins snug to the chuck against the spindle.

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Every accurate lathe I have worked on: Monarch 10ee, Leblond Toolmakers lathe, etc have all mated this way.

However I'll be happy to put the onus back on the proposal that there must be a space. Has anyone using a Kitagawa on a tool room lathe ever had a space? A Pratt Burnerd on a Monarch 10ee had a space? Go ahead, shock me! I can take it!

As far as my assertion that you can put a D1-X on cocked, just try it on your lathe - it is easy! (and wrong)

 

[Dabbler]

I sent an email to Kitagawa technical support, as Pratt Burnerd is no longer an independent entity. Let's see what Kitagawa says!

 

[extropic]

This is what you are looking for

To mount a chuck, the lathe operator inserts the pins into the spindle and rotates the cam, pulling the pins snug to the chuck against the spindle.

---

Every accurate lathe I have worked on: Monarch 10ee, Leblond Toolmakers lathe, etc have all mated this way.

However I'll be happy to put the onus back on the proposal that there must be a space. Has anyone using a Kitagawa on a tool room lathe ever had a space? A Pratt Burnerd on a Monarch 10ee had a space? Go ahead, shock me! I can take it!

As far as my assertion that you can put a D1-X on cocked, just try it on your lathe - it is easy! (and wrong)

You need to reread reply #8 again, more carefully and calmly. I never said there must be a space.

My chuck is more than "snug" against the spindle (taper), but there's a few thou gap between the faces.

 

[mksj]

Never had a chuck or used a lathe where there is a gap, if there was then I would expect the D1 pins when tightened to result in repeatability issues and some degree of axial alignment issues. Some lathes the chucks are easily released, others like my current one, takes a soft mallet or clamped bar to get the chucks off. But they all mount flush with no gap to the spindle mount. I have 7 chucks, they all mount the same. There have been a few people reporting a small gap between the chuck and spindle, in most cases it is a chuck QC issue. Better chucks may have alignment marks and a master pinion which aids in their repeatability.

 

[extropic]

Never had a chuck or used a lathe where there is a gap, if there was then I would expect the D1 pins when tightened to result in repeatability issues and some degree of axial alignment issues. Some lathes the chucks are easily released, others like my current one, takes a soft mallet or clamped bar to get the chucks off. But they all mount flush with no gap to the spindle mount. I have 7 chucks, they all mount the same. There have been a few people reporting a small gap between the chuck and spindle, in most cases it is a chuck QC issue. Better chucks may have alignment marks and a master pinion which aids in their repeatability.

To clarify, do you mean 7 chucks fit snugly on the taper and with zero gap, all on one lathe spindle?

If yes, did they arrive that way from the supplier(s) or did you modify something to achieve that fit?

 

[ddickey]

Mr. Crispin has some good videos on repairing D1 spindles and backplates.

 

[xr650rRider]

https://www.precisionmatthews.com/wp-content/uploads/2021/05/PM-ER40-Collet-chucks-V.1-5-2021.pdf

First page. Typical chuck fitment procedure.

I've got a 4-jaw, 3-jaw, backplate that came with PM-1340GT, added Bison 5C collet chuck and PM ER-40 chuck, they all fit the machine well and no gap. All but the 4 jaw takes a slight bump with deadblow hammer to release.

 

[mksj]

Seven chucks bought at different times over the last 12 years and used on two different lathes, chuck manufactures PM/QMT Taiwanese, PBA, Bison, TMX, and a generic Chinese. They all fit pretty much the same on both lathes with no gap between the chuck and spindle (D1-4). On my first lathe 1340GT they were a snug fit but could be removed easily when released, current lathe ERL-1340 (Sunmaster) they are all a tight fit and require a soft mallet or clamped bar to release from the spindle nose. They all fit the same on each machine. Also worked/used on quite a few other people's lathes, as far as I recall all the chucks would mount flush to the spindle with the D1 mounts. Those people that reported a gap on say one chuck it was usually a chuck QA issue, if all the chucks then the spindle nose was out of spec. and in some cases required some light stoning.

If there is any gap between the chuck and spindle then when tightening the D1 pins it will result in inconsistent mounting/repeatability. Even when they are flush mounting, I always tighten the D1 cams in a sequential fashion 3 times, increasing the torque on each pass. All the chucks have an alignment mark so they always mount in the same rotational position relative to the spindle. My scroll chocks are set-tru type and maintain a TIR of 0.0004" or better when removed and reinstalled in this manner. I do a lot of multiple ops where the piece is removed and then reinserted multiple times in the chuck, so maintaining a low TIR and chuck repeatability is very important.

Most recent 10" Bison chuck, given the weight (100+ lbs), and with a high centrifugal force, it would be dangerous to use if it didn't suck up flush to the spindle or if there were any wobble. Note the bar in the chuck for lifting and I also use it to release the chuck from the spindle nose as it is a very tight fit on this lathe.

 

[Dabbler]

I agree that it's not necessary for both the faces and the tapers to be in contact. According to some basic design principals, the requirement would be over constraining the chuck. The taper locates the chuck both radially and axially. Mine is a very unpopular opinion.

You need to reread reply #8 again, more carefully and calmly. I never said there must be a space.

Nice try to belittle me. I haven't ever been anything less than calm. However I assert that you are simply wrong. I did not disparage you. You are free to believe anything that you like. I do contest it as promulgating wrong information.

- As highlighted above, you did say that the face didn't need to touch, as the taper must always be in contact in any event. Due to elastic deformation of the taper, the system is not over-constrained.

I have 2 Pratt burnerd, 3 collet closers made in Germany, a backing plate if unknown origin and a recently acquired auto Sirone Strong (mistyped) chuck for my D1-6 cam lock on my LeBlond lathe - all mate as I have described. These have all been bought over 40 years and mate with the chuck frimly seating against the flat on the spindle.

- but one guy's experience doesn't really matter.

Talk to any tool and die maker of any experience and training and they will tell you the same thing.