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Chuck key sizes poll

Your lathe chucks key sizes

  • Total voters
    21
Why work so hard.....

Look in the various tool retailers/suppliers catalogs and see their listings as to what they are selling. This will give a very good idea what is popular as they will only stock what they can move.

"Teach someone to think and they learn, do the work for them they learn nothing."
 
I don’t have a lathe (yet) but i do have a 5” Pratt chuck on my Liang Yu dividing head. A good Kijiji find but had no key.
The chuck key hole is 10.6mm.
So I’d be very interested to buy a 10mm Toosmile tool.
(Now I’m using a 3/8” socket extension - a bit sloppy at 9.5mm but good enough that making one is way down on the to-do list.)
 
I am interested too. I actually tried to buy one on Amazon but they only had 11mm. My choice would be 10.

I too made my own wrenches. I just took the next biggest socket wrench extension to the grinder until it fit.

But I recently stopped using it.

I've read a few horror stories about using a tool with too much leverage. So I'm back to using the factory T-Wrench.

Other than the one posted by @TorontoBuilder a while back, I'm sure I'll never find the horror stories. But the danger is that tightening too much locks the cams and then they can't be loosened.

Unless I am badly mistaken, the design of a D1-x spindle is such that the nose provides the alignment and all the cams do is tighten the chuck against the spindle register. It doesn't take a lot of force to do this and once seated the chuck will not move. Additional torque provides no benefit.

The advantage of a T-Wrench is that it is very difficult to apply too much force because of the low leverage of the short handles.

The same principles apply to using wrenches on the Jaws. There is a lot of internal leverage using a scroll cam on a scroll chuck and the screw threads on an independent chuck.

I wish I knew what the target torques were. But I've never found that anywhere. It would change my life if I could setup a torque limiting system of some kind and use a bigger wrench or even a speed wrench like Smile's. For the time being, I am just careful not to take advantage of any leverage and/or to gronk on my wrenches.
 
Susquatch said:
The same principles apply to using wrenches on the Jaws.
Click to expand...
I've had the cringe when watching some youtube videos where they have a cheater on the chuck wrench. Some even that I know are very skilled, long term professional machinists. The cross sectional supported area on the scroll is not very large, and can be damaged. but it does amount to over a square inch in larger chucks. On a smaller chuck in a smaller lathe a beginner would certainly get the wrong idea, and damage the chuck.

What is very common, is gronking hard on their milling vise. If you need to put 8,000 lbs of force on your work, you are holding it wrong or milling it wrong. I once loaned a milling vise to a person I thought was experienced, and the damage to the vise took months and $$$ to repair. I finally sold it as it was a reminder of the bad experience every time I used it - this was before I joined the forum, BTW.
 
Here's one chart I found using Google Fu:

shop.cuddebackmachining.com

Torque / Clamping Force Chart

Speed Torq Handle™ Specifications Drive screws on milling vises can vary from one manufacturer to another. The smaller the thread pitch, the greater the mechanical force. (clamping force) Therefore, vises tightened with our preset Speed Torq Handle™ will have different clamping forces across...
shop.cuddebackmachining.com
 
Dabbler said:
Here's one chart I found using Google Fu:
Click to expand...

If I understand this, it's basically the applied screw force that is generated when tightening any threaded fastener. Odd that it didn't discuss lubricated vs unlubricated threads.
 
Kurt's chart is here: (scroll down to view it):

www.kurtworkholding.com

Kurt DX6 CrossOver Vise - DX6

Combining all the great features of our world-renowned Kurt Vises, along with new state-of-the-art workholding technology, Kurt® Workholding’s revolutionary DX6® CrossOver® vise achieves new levels in precision and performance where flatness and parallelism are important. Now Featuring a cast on...
www.kurtworkholding.com www.kurtworkholding.com
 
Anyone have any torque info on chuck keys and cam locks?
 
Last edited:
Here you go

IMG_1011.webp


IMG_1010.webp


And the manual for the DX6.
 
jorogi said:
So late to the party butwhat the heck.

Two lathes and five chucks.

SB9
Cushman 3 jaw scroll chuck.
Key 0.283
Chuck .299

Watson 4 jaw independent chuck.
Key 70mm
Chuck 72.8mm
Made the key for this chuck last weekend and coincidentally it fits the 3 jaw too which is a square hole but has grooves on the flats.

Bison 3" three jaw scroll chuck.
Key 0.231
Chuck 0.245

Colchester Dominion 15"
4 jaw no name independent chuck.
Key 0.510
Chuck 0.525

3 jaw Union Mfg. scroll chuck.
Key 0.423
Chuck 0.463

John
Click to expand...
Also late here...
South Bend 5" 3-Jaw Key about 0.355"
South Bend 6" 4-Jaw Key smaller at 0.29"
Both of the recesses for the keys are not totally square so the measurement is a bit iffy therefore I haven't bothered.

For the small rotary table an 81mm 4-jaw with 5.9mm hex key

The Gingery Lathe has an 80mm 3-jaw with 7.8mm key.

The other rotary table has a 100mm 3-Jaw with 7.8mm key

And finally the giant Unimat DB-200 doesn't use a key for the 3-Jaw but does for the 4-jaw. Diameter is 60mm with a 4mm square key. The jaws are restricted by the adjustment screws and so cannot completely close.
 
Us little guys don't worry too much about over-torquing things. As @Susquatch says, too much leverage is a horror show. Ever had to remove Bruno The Shotput Champ's threaded-on lathe chuck?

My lathe 3-jaw and 5C chucks use 10mm keys, so I use a 3/8" socket-wrench extension and a little 4" long stubby ratchet. I really like A Smile's design. time to blow the swarf off my wallet and open it.

Speed handle for my milling vise is a 4"-long cast iron crank from a 3/4" plug valve, with a 1/4" drive deep socket pined together with a roll pin. The roll pin breaks when I do something stupid.

IMG_3505.jpeg
IMG_3506.jpeg
 
I thought we would have the new member type "Limited Commercial" up and operating but I need Josh to do stuff on the backend. We've setup the rules and I'll be one of these new limited commercial members when we get things finished. In the meantime I've got a sales site going with paint mixers and @a smile chuck key wrenches in 10,11,12mm sizes. I'm helping @a smile with his sales in Canada. The sales site is a square.com provisioned site with the full stack of credit card acceptance, paypal, SSL security etc. Square is similar to shopify as a provider of these services to people who want to run a store but not handle the complicated credit card online details themselves. Like me for example. I don't even know the customers credit card numbers and I don't need to or want to either.

Have a look.

 
I thought all my sizes were the same as everybody else's -- but no.

On my 12" lathe, the 7 1/4" 3J, key is 11mm; and the 8 1/4" 4J, key is 10mm
14" lathe, the 7 3/4" 3J, key 12mm; 7 3/4" 4J, key is 11mm
15" lathe, the 10" 3J, key is 11mm, 12.5" 4J, key is 14mm HEX.
my little 6" 3J, key s 3/8"

I've had a chance to try out the new key from @a smile - what a well made thing! the main shaft is very well machined, the lockable sliding handle is stainless steel. Smooth operation, clever design. I tried it out on @Janger's lathe and it was very nice! I now own an 11mm version.
 
Dabbler said:
I thought all my sizes were the same as everybody else's -- but no.

On my 12" lathe, the 7 1/4" 3J, key is 11mm; and the 8 1/4" 4J, key is 10mm
14" lathe, the 7 3/4" 3J, key 12mm; 7 3/4" 4J, key is 11mm
15" lathe, the 10" 3J, key is 11mm, 12.5" 4J, key is 14mm HEX.
my little 6" 3J, key s 3/8"

I've had a chance to try out the new key from @a smile - what a well made thing! the main shaft is very well machined, the lockable sliding handle is stainless steel. Smooth operation, clever design. I tried it out on @Janger's lathe and it was very nice! I now own an 11mm version.
Click to expand...
I would like to know whether all your sizes are the metric size of the standard configuration of the chuck or the approximate data after conversion in imperial system?

I hope that the size of the tool is just enough to plug in and pull out smoothly. I don't like too much gap, so I hope to have more accurate size data support.

I'm glad to hear your comment on the key, but it's a pity that what you have is 11mm, which is my first commercial product, I think I found a substandard processing company, they did not produce the product according to my requirements. 1. The appearance is not silver as I hoped. 2. There is no chamfering in the details, there is a very sharp Angle, it is easy to get hurt, and there are burrs in some places. 3. The surface of the booster rod is very rough. 4. The pitch of the nut is 1.5mm, which is also the reason why I changed the pitch to 1mm. This is also the reason why I have no confidence in selling, but I can't withdraw my product because of the huge cost. They have been stored in Amazon warehouses in the United States.

I think, from a mechanical enthusiast to become a mechanical enterprise is not easy, simple mechanical production can be unlimited pursuit of perfection, the cost can be ignored. But businesses have to consider costs, and sometimes they have to give up some ideal perfection. The number one reason I make all my pieces is because I'm going to use it, so I try to make it close to my habit. But if it's a business, you have to accept some other people's habits, so thank you very much JOHN for doing the research for me, I think I learned a lot from it.
 
I forgot to add the my D1-4 camlock in the 14" lathe is 10mm, and my D1-6 camlock on the 15" lathe is 13mm.

In all cases, I measured the actual chuck wrenches, except for the 3/8" 6" chuck, (I don't have the key for it) Each chuck is different about the clearances. In some cases it was about .5mm, I think the maximum clearance was about .7mm.

The one I tried out was 10mm on @Janger 14" lathe.

To get a key that would fit the most chucks I needed 11mm, but it is a pity I have so many sizes of sockets. My long term plan is to keep the 15" lathe and sell the other 2. But then I would be using 11mm and 12mm square, and 14mm hex all the time.

Oh, and 3/8 for the 6" 3jaw and whatever I settle on for a tiny 4J chuck, but probably 3/8" again [these are to hold small parts without changing to a collet chuck]
 
Dabbler said:
I forgot to add the my D1-4 camlock in the 14" lathe is 10mm, and my D1-6 camlock on the 15" lathe is 13mm.

In all cases, I measured the actual chuck wrenches, except for the 3/8" 6" chuck, (I don't have the key for it) Each chuck is different about the clearances. In some cases it was about .5mm, I think the maximum clearance was about .7mm.

The one I tried out was 10mm on @Janger 14" lathe.

To get a key that would fit the most chucks I needed 11mm, but it is a pity I have so many sizes of sockets. My long term plan is to keep the 15" lathe and sell the other 2. But then I would be using 11mm and 12mm square, and 14mm hex all the time.

Oh, and 3/8 for the 6" 3jaw and whatever I settle on for a tiny 4J chuck, but probably 3/8" again [these are to hold small parts without changing to a collet chuck]
Click to expand...
May I request that you test the square dimensions of the inner holes of each chuck? Are you sure these sizes are not using metric keys that are close to the imperial size?
 
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