# Spindle adapter.  2 1/4 - 8tpi to 1 1/2 - 8tpi



## Thoro (Jan 4, 2015)

Some of you may recall a member here asking about a spindle adapter a while back 
http://www.hobby-machinist.com/show...e-10-k-chucks-on-a-heavy-10?highlight=adapter. 

 His needs were that he had some chucks for his 10K (1 1/2" - 8tpi spindle)  that he wanted to be able to use on his heavy 10 (2 1/4" - 8tpi spindle) without switching or investing in additional backplates.  So I contacted him and he commissioned me to design and make him one.  

For me, this was a first and I wasn't sure if it would be practical in the end, but I think it turned out quite well and he certainly was happy with it as well.

It started off as a roughly 3" solid round cold rolled piece of steel.  

So I thought it would be appropriate for me to share this with you all.  Here are some pictures.


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## atwatterkent (Jan 4, 2015)

Beautiful application and machining.
Next week I'm doing the same thing for my 14 1/2" SB with a 2 3/8"-6 spindle that I'm getting too old to pick up the 9" chuck for.
Thank you for the inspiration.

Yes I have a 10K with 1 1/2"-8 chucks too.
I'll put a couple of holes in it though and make a pin spanner for removal


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## Thoro (Jan 5, 2015)

atwatterkent said:


> I'll put a couple of holes in it though and make a pin spanner for removal



Thanks for the compliments.  Only thing is you might consider the added stresses on the spindle bearings.  I would only use the adapter in a very moderate fashion, for less demanding operations (this is what JoeBiplane needs it for, light work.

I actually forgot that I did put a hole in it for an 2 3/4" pin spanner.  Works great to remove the adapter!


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## atwatterkent (Jan 5, 2015)

I really don't see a problem with bearing stress considering the weight of a small 5" chuck compared to a 9" chuck that weighs well over 50 lbs. and. sticks out about as far from the headstock as the 5" with the adapter. I think I'd be more worried about tearing up the smaller chuck which is a NOS SB chuck I found a couple of years ago. I didn't think anything like it could exist unused.
Thanks for mentioning your concerns though.


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## atwatterkent (Jan 13, 2015)

Design question: How much steel between the end of the inner bore and the register face of the 1 1/2-8 thd.?


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## Thoro (Jan 13, 2015)

I will have to look at my drawing and get back to you tomorrow, as it is at the shop.


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## Mark_f (Jan 13, 2015)

I'm impressed. I think it is fantastic and I wouldn't be worried about stressing the bearings (my opinion)
:thumbzup3:


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## Thoro (Jan 20, 2015)

atwatterkent said:


> Design question: How much steel between the end of the inner bore and the register face of the 1 1/2-8 thd.?




Sorry it took me a while to get back to you.  I forgot...

It is very close to 3/8"  give or take, that was my target.


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## joebiplane (Jan 21, 2015)

Thoro said:


> Some of you may recall a member here asking about a spindle adapter a while back
> http://www.hobby-machinist.com/show...e-10-k-chucks-on-a-heavy-10?highlight=adapter.
> 
> As the recipient of Thoro's engineering and his craftsmanship...  I have to say it is EXACTLY WHAT I HAD IN MIND"   It works,  for my needs,  extremely well    making me   :victory:   " Happy as a clam at High Tide"
> Joe Larsen   :thumbzup3:


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