# Bison set tru D 1-4 spindle mounting has to many studs



## Swerdk (Oct 29, 2018)

My Chinese chuck back plates have d1-4 adaptor with only 3 studs 
	

	
	
		
		

		
			





I will be buying a Bison 6 jaw 6” set tru chuck but the only adaptor plate that they offer has 6 studs




Model number for d1-4 adaptor plate is 7-875-064

How do I fit the square into the circle. What am I missing


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## Swerdk (Oct 29, 2018)

Forgot the lathe spindle pic 






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## talvare (Oct 29, 2018)

Remove three of the cam lock pins from the new backing plate.

Ted


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## old_dave (Oct 29, 2018)

What is the source of the illustration? I have a strong hunch that they are simply showing the wrong backing plate. Let me be a little more emphatic: the backing plate shown is simply not a 4 inch type D-1 (to use the strict nomenclature)

David


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## Swerdk (Oct 29, 2018)

That’s weird every site I typed the model # in I get the same pic. It’s a conspiracy. So if somehow THAT adaptor plate was mailed to me can I leave out 3 studs and not compromise integrity of it? 


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## Swerdk (Oct 29, 2018)

Btw thanks for proper nomenclature. Never knew proper way to reference D 1-4


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## old_dave (Oct 29, 2018)

Well I was being a little tedious there. My copy of  USA Standard B5.9 (Reaffirmed 1992) "Spindle Noses for Tool Room Lathes, Engine Lathes, Turret Lathes, and Automatic Lathes" gives the correct nomenclature for the cam lock spindle nose as Type D1 preceded by the nominal size, in this case ""4-in. Type D1" We're probably going to be better off using the customary nomenclature, D1-4" that everyone is used to.

David


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## talvare (Oct 29, 2018)

Swerdk said:


> So if somehow THAT adaptor plate was mailed to me can I leave out 3 studs and not compromise integrity of it? Sent from my iPhone using Tapatalk



I believe the D1-4's only have three pins, but I have seen several instances of the larger D1 chucks being used with three of the pins removed.

Ted


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## old_dave (Oct 29, 2018)

Please let us know what arrives.
David


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## mksj (Oct 30, 2018)

A D1-4 has specific dimensions and has 3 pins. You can see a picture and dimensions at the Toolmex site which distributes the Bison chucks. Each D1-X size is unique, so they are not interchangeable by removing pins. Also Gator back plates are pretty much interchangeable with Bison/TMX at about 1/2 the cost if just buying the back plate. I like the Bison/TMX chucks, Ii have ther 8" combo and their set-tru 5C which I use 90% of the time.
https://www.toolmex.com/itemdetail/7-875-064


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## Tozguy (Oct 30, 2018)

old_dave said:


> What is the source of the illustration? I have a strong hunch that they are simply showing the wrong backing plate. Let me be a little more emphatic: the backing plate shown is simply not a 4 inch type D-1 (to use the strict nomenclature)
> 
> David



As Mark wrote the D1-4 spindle has three pins and always will, nothing else will do for your spindle. 
Page 36 of this document 
http://www.lathe.com/toolmex/Bison_Set-Tru_Chucks.pdf
will show the dimensions of the different D1 sizes. 

Checking the link that Mark provided above it shows a 3 pin backplate but that part number has been replaced by another. The picture Toolmex provides of the new D1-4 backplate has 6 pins, obviously a mistake in choice of picture by Toolmex.


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## rwm (Oct 30, 2018)

Can someone explain the rationale of this nomenclature. My lathe uses a D1-3 mount. It has 3 pins that are smaller than a D1-4. No dimension on the mount is 3". What does the last number represent? What does D1 represent? Is that the taper?
Robert


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## JimDawson (Oct 30, 2018)

rwm said:


> Can someone explain the rationale of this nomenclature. My lathe uses a D1-3 mount. It has 3 pins that are smaller than a D1-4. No dimension on the mount is 3". What does the last number represent? What does D1 represent? Is that the taper?
> Robert



It's the approximate diameter of the spindle face, rounded to the nearest integer.  D1 is the type or style designator.


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## old_dave (Oct 30, 2018)

Here's more, probably much more than you want, mostly from Standard B5.9. First of all the spindle diameter for each nominal size: 2" = 2 5/8", 3" = 3 5/8", 4" = 4 5/8", 5" = 5 5/8", 6" = 7 1/8", 8" = 8 7/8", 11" = 11 3/4", 15" = 15 7/8" and 20" = 21 1/2". Note these dimensions are given in inches and fractions thereof. Sizes 2" - 4" have 3 cams, sizes 5" - 20" have 6 cams. I'm not sure who is responsible for this design, it may have been a collaborative effort among the U.S. lathe builders of the day. Monarch first offered the cam lock spindle nose on its machines in 1935. I think Pratt & Whitney was also an early adaptor. (Date for Monarch's offering this is from John Legge's history of that company which can be accessed through lathes.co.uk). The first version of the Standard itself is dated 1936. The next version of the Standard, dated 1948, added the 2"and 3" type D1 sizes as well as the long taper, the Type L,  series (L00, L0, L1 etc.) Note that while the 3" Type D1 wasn't included in the Standard until 1948, we know the design already existed as Monarch used this on their 10EE which came out in 1939. It's also one size smaller than what the Standard specifies for this size toolroom lathe.

So Standard B5.9 gives the spindle nose size that should be used for which size of lathe. I've never seen a 2" Type D1 spindle nose, but according to the Standard, if Myford had put a cam lock spindle nose on their Super 7, this would have been the proper size.

And "Type D1" means that it is a cam lock spindle nose. There was no "Type D2". Writers of the Standard may have wanted to leave open the possibility of later variations that would call for further division in the nomenclature There are both Type A1 and A2 (and B1 and B2) spindle noses. These are similar to the Type D1 except the chuck is secured by through bolts or cap screws in to tapped holes. These are typically used on turret lathes and now, CNC lathes.

Finally the cam lock spindle nose seems to have prevailed over the long taper. I'm not aware of any lathe currently made that uses the long taper spindle nose.

David


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## rwm (Oct 30, 2018)

My Southbend D1-3 does indeed have a 3.625 spindle face. Thanks for the info.
Robert


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## Swerdk (Nov 7, 2018)

I rcvd new back plate made by bison and thankfully it turns out that the pictures with 6 studs are wrong as my backplate only came with 3 studs. I am all set. My new bison chuck is so shiny and clean can’t wait to try it out. Thanks again for input


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## old_dave (Nov 7, 2018)

Thank you for this report. I like it when things make sense.
David


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