3 Jaw D1-4 Chuck

If "any tool and die maker of any experience and training and they will tell you the same thing", shouldn't there be plenty of credible published documentation? Where are the text books? Where is the credible published documentation? Were they all trained by word-of-mouth?

The Pythagorean theorem is important in machining and tutorials with solution calculators for right triangles are all over the place.

Where is the credible published documentation stating there must be zero gap between the faces?

The Precision Matthews document linked (reply #18) by @xr650rRider says any gap should be filled with a shim. OK, that's one document for the zero gap side. Each reader/owner will decide for themselves how to respond to that document.
I think making a steel shim (the size and with the holes required for my D1-4) precisely flat, parallel and a few thousandths thick is a difficult task. I suppose a shim could be CA glued to the chuck to prevent contamination under the shim and prevent the shim from being a loose part subject to damage.

I hope Kitagawa responds to @Dabbler.

I also sent the following to Pratt Burnerd America (info@prattburnerd.com)

Pratt Burnerd America

Hello,                                                                  2024-09-26

Please refer the following to an expert in manual chuck mounting.

When I mount my D1-4, 3 jaw chuck, there are a few thousandths of an inch of clearance between the planar faces of the spindle nose and the back of the chuck. My question is, is that a proper mounted condition or must there be zero clearance between the planar faces?

All related surfaces are free from damage and contamination and the cam lock pins are properly torqued.

If zero clearance between the planar faces is a requirement, I would like to read a document defining the requirement. Can you provide me with the documentation of the requirement or inform me precisely where to locate it?
Because achieving such a requirement would require lapping the chuck taper to match the lathe spindle taper, I wonder if you can provide a recommended procedure for the lapping.

Regards,

If I get a reply, I will post it in this thread.
 
I should say that I'm not ignoring, or discounting, the statements by @mksj and @Dabbler that they have numerous chucks that fit with zero gap without any modification.

I have not had the same experience that they describe. I don't think that any of my chucks/faceplates fit with zero gap, regardless of all the elastic deformation that the cam lock pins can generate. I haven't perceived any problems with the gap. No sign of fretting (wear) on the spindle or accessories. I'm just a hobby machinist with a 12" x 36", Taiwan built, probably 90's vintage lathe and I haven't needed to attempt any extreme workpieces or extreme cuts. Most work is close to the chuck or supported by the tailstock/steady rest/follow rest, so moment forces are intentionally kept to a minimum because it seems like good practice.

Also, I haven't had access to calibrated/certified gages to inspect the conformance of my spindle or chucks with ASME B5.9 1967. I suppose that buying a set should be my first step when I win that Lotto.

I do own a copy of the ASME B5.9 1967 specification document and I explained (reply #8) what I see there.

Again, where is the credible published documentation of the zero gap requirement? If the requirement is real, the documentation should be abundant.
 
extropic said:
Again, where is the credible published documentation of the zero gap requirement? If the requirement is real, the documentation should be abundant.
Click to expand...
If there should be a gap, where is the credible published documentation that a gap should exist? If that is a real thing, then the documentation should be abundant.

Frankly this is so basic that all the D1x lathes I have worked on (more than 30) across 6 tool and die shops, have all worked the way I described. You have one non-conforming lathe and that doesn't mean it is right for everyone else.

Use your lathe the way you see fit. You have that right. Don't tell beginners that it is the way all lathes should work.
 
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