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Chuck key sizes poll

Your lathe chucks key sizes


  • Total voters
    21

Janger

(John)
Vendor
Premium Member
Hi Everyone,

I'm trying to help @a smile with his lathe key product. He is making these lathe chuck keys and has 10, 11 & 12mm sizes. He wants to know if these sizes are enough or if he also needs to make some imperial sized chuck keys. 5/8", 1/2" 3/8, 1/4" or even smaller sizes. 9mm


jpg.38165


So to help him understand what people might want I'm putting up this poll to ask what size lathe keys you have in your shop. Please vote multiple times with the different sizes you have. I have 10mm and one 3/8”. If you pick other would you please reply to the thread and say what size other is for you?
 
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YYCHM

(Craig)
Premium Member
Craig - 7.5mm is 0.295". Both of those seem odd to me. Are you measuring the key or the chuck? try the chuck?

Ok, I measured the chuck and got 7.61mm ? I assume this means across the flats and not on the diagonal?
 
Last edited:

Janger

(John)
Vendor
Premium Member
Well 7.61mm is 0.2996” so 0.3”. That makes more sense than 7.61mm. What kind/brand of chuck and where was it made?
 

YYCHM

(Craig)
Premium Member
Well 7.61mm is 0.2996” so 0.3”. That makes more sense than 7.61mm. What kind/brand of chuck and where was it made?

"emco" for one and I think the other one is a South Bend. Have no idea where they were make. Both are 4 Js.
 
Last edited:

trlvn

Ultra Member
The 125mm 4-jaw chuck that came with my Craftex lathe uses a 7mm square drive so one of my votes was for "Other".

Craig
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
I'm trying to help @a smile with his lathe key product. He is making these lathe chuck keys and has 10, 11 & 12mm sizes. He wants to know if these sizes are enough or if he also needs to make some imperial sized chuck keys. 5/8", 1/2" 3/8, 1/4" or even smaller sizes. 9mm

I will measure all mine later today when I get to the shop and complete your survey when I do.

Consider expanding the survey to cover all options. Ie half metric as well as all Imperial from say 4mm to 5/8. It will be a very long list but in this case I think it's important enough to warrant that confusion. The final numbers will speak for themselves.

I'd bet that @a smile prolly wants to cover what is popular and the rare ones will just have to be user modified to fit.

PS - GREAT IDEA to do this for him.
 

Janger

(John)
Vendor
Premium Member
Susquatch the poll only allows 10 choices. So it’s hard to cover everything. I’d like another option for hobby shop, some industrial, and industrial shops.

Members who work at industrial facilities can you please vote on the sizes at your work?
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
Apparently, I have 9, 10, and 12 in my shop. No imperial. And no, the 12 is not 1/2 because the socket is smaller than 1/2.

Lots of slop in the fit too on all of them. The difference between the wrench and the socket on the chuck varies from 0.2mm to 0.4mm. In all cases, an exact metric wrench would fit the socket. So I'm fairly confident of the above.

Edit - The size I use most is 10mm by a very wide margin. I have three chucks that take a 10mm wrench.

Edit 2 - I missed one 3/8 chuck. I will update my survey shortly.
 
Last edited:

Upnorth

Well-Known Member
I'll try and measure mine tomorrow. I actually do need a chuck key for one of them If I remember right it's hex shaped not square.
 

Upnorth

Well-Known Member
I just measured the two I actually use. One is 3/8" square and the other is a 12mm hex. I also have 3 more chucks that I didn't measure. One is going to be used for fixturing small parts, second is an old chuck too big for my current lathe, the third is an air chuck.
 

6.5 Fan

Ultra Member
Premium Member
The Craftex 3 and 4 jaw chucks use total different sizes, 4 jaw is 7mm, the 3 jaw is 10mm, and my old 3 jaw on the colchester is 5/8".
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
A very expensive chuck, uses compressed air to close the jaws, suited to production work, also there are hydraulic chucks.

That's enough info for me. I get the idea. I can readily picture the production facility. I no like.
 
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