# Lathe Chuck question



## MarkD (Jul 5, 2011)

I have a 1" x 8tpi PSI collet chuck for my wood lathe. I would like to be able to use this collet chuck on my Grizzly Lathe/Mill combo.

Rather than having threads on the end of the Grizzly lathe spindle ( like a wood lathe ), the end of the spindle has a faceplate and the 3 jaw chuck is screwed to that faceplate. 

Does anyone know of an adaptor or another way to use the collet chuck on this type of configuration?

I was thinking that maybe If I could find some kind of of adapter with a shaft that I could use in the 3 jaw chuck, and 1" x 8" threads on the other end that I could mount my collet chuck to. Not sure how accurate the chuck would be when used in this manner though.

Any suggestions?


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## randyrls (Jul 5, 2011)

MarkD said:


> I have a 1" x 8tpi PSI collet chuck for my wood lathe. I would like to be able to use this collet chuck on my Grizzly Lathe/Mill combo.
> 
> 
> I was thinking that maybe If I could find some kind of of adapter with a shaft that I could use in the 3 jaw chuck, and 1" x 8" threads on the other end that I could mount my collet chuck to. Not sure how accurate the chuck would be when used in this manner though.
> ...




Mark;   Depending on the spindle thread, you might be able to find an adapter.  But if your lathe has a 39x4mm metric spindle thread, you probably not be able to find one.

If you don't want an MT taper chuck, the only alternative is to use a back plate that fits the spindle, and a collet chuck face plate.  There is a registration flange that connects the face plate to the back plate.

This web page show how to make a threaded collet chuck from scratch.
http://www.akpilot.net/ER-32 Collet Chuck/ER-32 Collet Chuck.html


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## MarkD (Jul 5, 2011)

The problem is that the spindle does not have threads, all It has a faceplate. The 3 jaw chuck is screwed to the faceplate. I believe I'll either need to make my own adapter that will attach to the face plate OR I'll find some kind of adapter that has 1" x8 tpi threads on one end and something I can put in the 3 jaw chuck on the other end. I can then attach the collet chuck to the 1x8tpi threads,


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## PenMan1 (Jul 5, 2011)

Mark:
If my memory serves me correctly, the faceplate screw on tbe Grizzly metal lathe has a center hole that is 3/4" x 16 tpi.

If you can take the 3 jaw chuck to a hardware store and confirm that size, several companies make a 1" x 8 tpi to 3/4" x 16 tpi converters.

I THINK I remember seeing them advertised at Little Machine Shop and Harbor Freight.


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## holmqer (Jul 6, 2011)

Assuming that you have the G0516 (Grizzly badged Seig M6 model 500. which has an X2 mill attached to a C6 model 500 lathe.), the spindle bore is MT3, and the chuck mount is the 125 mm variety unlike the 90 mm found in most 7x lathes.

You have several choices

If you wish to maintian the ability to pass round stock through the collet into the spindle bore, you can;

Make an adapter plate that either fits into the jaws of the chuck and has a 1x8 nose to thread the collet chuck 

Make an adapter plate that has the same bolt pattern as the chuck mount and has a 1x8 nose to thread the collet chuck. 

Make a collet chuck that has the same bolt pattern as the chuck mount. (might be easier since the M40x1.5 thread is in range for the gearing of the lathe unlike the 1x8)

Buy a new collet chuck that already has the bolt pattern
http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Lathe-Collet-Chucks
code 050-110-32650

If you can live without passing round stock through the headstock then turning a adapter from 1 1/2 inch stock that has 1" tenons on either end, one of which you thread 1x8 would be fairly easy. Put the unthreaded end in the chuck jaws. You would want the larger stock to have a shoulder to allow the collet check to register against one side and to register against the lathe chuck on the other


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## Daniel (Jul 6, 2011)

The collet chuck on my mini metal lathe 7X12 is a morse taper. it also has to be kept there with a bolt.


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## BigShed (Jul 6, 2011)

If it is the Sieg C6/Grizzly G0516 the chuck mounting is non-standard and is discussed here in detail.


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## MarkD (Jul 6, 2011)

I just got home and did some investigation.
What I have is a Grizzly G4015Z lathe/mill combo.
I took off the 3 jaw chuck ( not the easiest task to remove the 3 cap screws ). 
With the 3 jaw chuck off I found that the spindle has a 4" backplate. The backplate has a portion  that sticks out a bit which I think is used to align the chucks. The diameter of this is 2.83" which is about 72mm. The lathe spindle does had a 3MT taper to it,,,,if that helps.
From what I have seen on the sites you guys indicated it does not appear to be something standard.


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## BigShed (Jul 6, 2011)

Mark, I'm not familiar with that machine and where it comes from (Grizzly doesn't make anything).

There is however a Yahoo user group for these machines and you may get some better answers to your questions there.


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## holmqer (Jul 6, 2011)

From your description, it appears to be a standard 4" mount. The standard registration recess for a 4" is 72mm. If it uses 3 M8 that is further evidence. If the bolt holes are 72.75 mm (84 mm * cos 30) apart, then this would indicate an 84 mm bolt pattern (D2 in the chart below)

http://littlemachineshop.com/Info/lathechuck.php

Looking at the specs for your machine, you can gear it to cut either the 1x8 or M40x1.5 threads, so you can make either your own ER32 collet chuck (Collet nut is threaded M40x1.5), or a 1x8 adapter.


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## MarkD (Jul 6, 2011)

This is the machine is http://grizzly.com/products/G4015Z
It looks like it was recently discontinued. 
It's the same machine as the Shop Fox M1018.


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## MarkD (Jul 6, 2011)

holmqer said:


> From your description, it appears to be a standard 4" mount. The standard registration recess for a 4" is 72mm. If it uses 3 M8 that is further evidence. If the bolt holes are 72.75 mm (84 mm * cos 30) apart, then this would indicate an 84 mm bolt pattern (D2 in the chart below)
> 
> http://littlemachineshop.com/Info/lathechuck.php
> 
> Looking at the specs for your machine, you can gear it to cut either the 1x8 or M40x1.5 threads, so you can make either your own ER32 collet chuck (Collet nut is threaded M40x1.5), or a 1x8 adapter.



I had not found that chart yet! Thanks for verifying that.


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