What's new
What's new

Anyone Make Their Own Chuck Key? (Using only a lathe)

Kevin T

Stainless
Joined
Jan 26, 2019
I don't have any real projects going at this time so I have been thinking about making a couple chuck keys for the chucks I use the most. I don't really have any good chuck keys. I like good tools so something to my standards would be nice. I can't visualize how I might make the square engagement part though...using just a lathe.

I'm thinking I could use my power hacksaw to cut the square part and clean it up with a file but before I do I want to see if anyone else has tried this and has anything to share.
 
I don't have any real projects going at this time so I have been thinking about making a couple chuck keys for the chucks I use the most. I don't really have any good chuck keys. I like good tools so something to my standards would be nice. I can't visualize how I might make the square engagement part though...using just a lathe.

I'm thinking I could use my power hacksaw to cut the square part and clean it up with a file but before I do I want to see if anyone else has tried this and has anything to share.

I'm about as lazy as can be, so I USED TO .. just BUY the square part ... and fab a Tee handle.
'
'Got more money, started using socket-wrench tee handles.

Got older and wiser, just buy several chuck wrenches, all sizes, throw the f*****g "ejector" spring nonsense in the trash bin, keep a stash handy.

Some start at all of nine US dollars. Some cost more.

They might strip or bend? Pilgrim? They HAVE to.

The CHUCK is the hard and costly part to repair. The wrench is MEANT to limit the amount of damage "Bubba" can crank into it with a cheater bar.

Price the actuator pinion on a scroll chuck. Or the screws of a four-jaw.
Which one woud you want to fail first, at how much spend, and how long a downtime?

Annnnnd...

Lots of "stuff" around a shop needs my time that I CANNOT so easily "just buy".

So.. at least you might be well-off to "just buy" the squarey-ish part?

All it needs is the corners chamfered. BFD. Bench grinders exist.
 
Yes, more than once, lots of chucks. Mine beat any commercially made, no kidding.
Piece of cake;
a] Use a milling attachment, part 4 jaw chucked to index.
b] Outside broach the flats, like keyway work in reverse.
c] Grind, sand or file.
It'll not be as satisfactory without flats joining shank by generous radii. Bad ones are made that way and twist right off.

Beforehand use gauge pin to find absolute largest dimension of square. Use caliper to estimate across corners; geometry won't solve it, none made accordingly. The fit should be as much of a 'slip fit' you are capable. Won't just fall out, nobody likes that, ESPECIALLY with 4 jaws.

Make the shank roughly same diameter as original, but turned from larger material. Preserve that larger portion for the cross handle of sturdy tubing [mine are 4130] for handle, plug ends if you like. It's convenient to make handle slide off center for extra torque but center normally. In the shank, a plunger detent [not a ball] will do fine, spring, plug screw.

Chuck size not mentioned. Not so noticeable for a 6 or 8, plain delightful with a 15".
Then post build pics and glowing reviews.


Next?
 
OP.. if bored, much better projects to invest into..

1x2x3 blocks with custom hole patterns
angle plates
V blocks
vise stops
etc etc

stuff you might want/need not readily available...

As bill said, (more or less), buy a chuck key, take off the crappy spring detail, (providing you don't have numskull employees), make something useful for your shop
 
To make the flats for the square only using your lathe. . . Use lathe un-powered. Mark 4 points on your chuck, all 90 degrees apart, with a reference pointer fixed from headstock, that you can index point to each 4 marks on chuck, when its their turn.

Again lathe un-powered, lock spindle at point 1. Use carriage like a shaper. Keep feeding in a little after each carriage sweep till you clear one surface. Good use for a carriage stop on how long you want square. Finish one flat, unlock/relock spindle at position 2. . .

Not a chuck key, but just read an old thread of a pm member making their own Sjogren chuck from scrap and old car auto trans gears. If you scroll down the thread a bit to post #9, it shows a steady rest he made as well. Makes me want to up my game :D:
J King's Shopmade Sjogren
 
1/4" squre drive extensions fit some tiny chucks; 3/8" square drive extensions fit many smaller chucks; and 1/2" drive and 3/4" dirve some larger ones. If a bit too large, take the three sides down that don't have the retention ball down with a file.

Make a pair of them for your 4 jaw chuck.

Best thing to work on in your spare time? Maybe adding some sort of milling machine.
 
If you have a quick change tool post like I do,

Then get your holder out with the VEE groove for holding rod tools.

Clamp round stock in the tool holder and chuck an end mill in the lathe.

Cut a flat. Then rotate the round bar by eye and cut another flat.

Use a square to ensure your close enough to square and continue.

This is how I made 1 chuck key.

You don’t need to blue up and edge find for a chuck key. Square enough works great!
 
Just turn the end to the corner-corner distance and file four flats, why mess with a bunch of setups?
 
Just turn the end to the corner-corner distance and file four flats, why mess with a bunch of setups?

This would be max 10 mins of filing for even a big chuck key. It's surprisingly easy to file a square, square x 1.414 to get the full diameter, for 1/2" square full diameter is 0.707", file one side till flat to opposing side measures 0.6035", flip 180 degrees and file to 0.5". Turn 90 degrees and repeat. In real life you don't actually want sharp corners so turn the start diameter a little undersize, less filing and better looking key.
 
Just turn the end to the corner-corner distance and file four flats, why mess with a bunch of setups?

+1 filing. Make the OD of the starting cylinder small enough so you end up with non-sharp points on the square. Bonus idea: make a roller filing
rest with your lathe (and a hacksaw).

Obligatory back when I was a boy statement: Most apprentices have to hand-file a dodecahedron that just barely fits into any one of 137 different
positions in the master's test plate. Bonus points there if it is shining and summons a being from another dimension. In a church steeple. In the dark. At night.
 
+1 filing. Make the OD of the starting cylinder small enough so you end up with non-sharp points on the square. Bonus idea: make a roller filing
rest with your lathe (and a hacksaw).

Obligatory back when I was a boy statement: Most apprentices have to hand-file a dodecahedron that just barely fits into any one of 137 different
positions in the master's test plate. Bonus points there if it is shining and summons a being from another dimension. In a church steeple. In the dark. At night.

What kind of nonsense is that??! What real world application does that have. Sure, might teach them patience and finesse, but walk into a shop and tell the boss you're going to file that part square and se what happens. Maybe in your garage without a proper machine, but a shop with milling/grinding/turning equipment... ? don't think so.
 
What kind of nonsense is that??! What real world application does that have. Sure, might teach them patience and finesse, but walk into a shop and tell the boss you're going to file that part square and se what happens. Maybe in your garage without a proper machine, but a shop with milling/grinding/turning equipment... ? don't think so.

...recalls stories from Forrest about cape chiseling keyways in some shaft in the middle of a shipyard...
 
Thanks for all the replies guys! I wasn't expecting so much input thanks! (Must have been a slow day on the other forums hahaha!).

I'll take a bit from each of the good suggestions and give it a go.

I'm using socket drivers now with "T" handles but I always knew that these tools will need to go back into the socket drawer!

These Keys occupy a prominent place in my workspace so crafting something that looks nice, that I made is appealing.
 
Easy enough to mill the flats using a homemade angle plate and a collet mounted end mill.

Square the angle plate to the lathe cross slide first and then use a square or 123 block registered against the angle plate and against the first milled flat to rotate the key 90 degrees for the next cut. Then step and repeat.
 
Easy enough to mill the flats using a homemade angle plate and a collet mounted end mill.

Square the angle plate to the lathe cross slide first and then use a square or 123 block registered against the angle plate and against the first milled flat to rotate the key 90 degrees for the next cut. Then step and repeat.

Some of the guys that replied know I have a good selection of QCTP holders and I'll think about this a bit more. I have not had great experiences with using end mills with my lathe. When I tried I was able to achieve the desired result but the process wasn't comfortable for me....lot's of chatter and broken, although not high quality, end mills. I am getting better at setups and lately going through my machine I have been finding ways to adjust slop out of my worn carriage components too so maybe it will work better now.
 
When we were apprentices, we had to use hacksaw and files to make V-blocks, vises, and other tooling. It taught us to be precise with a file and be able to take off a .001" if necessary and make square and flat cuts. I still file parts when it is faster than setting up in a machine. When fitting one part to another as gunsmith, we file and use stones all the time for precision fits.
 
Good use of a hacksaw and files are very underrated IMO.
Problem may be who taught you the hows.
So often I see things done here that just make me cry but I do so remember the days of doing it all wrong.
Bob
 
Some of the guys that replied know I have a good selection of QCTP holders and I'll think about this a bit more. I have not had great experiences with using end mills with my lathe. When I tried I was able to achieve the desired result but the process wasn't comfortable for me....lot's of chatter and broken, although not high quality, end mills. I am getting better at setups and lately going through my machine I have been finding ways to adjust slop out of my worn carriage components too so maybe it will work better now.

Be sure to use a good quality cutting oil and take light cuts. Milling on most lathes is more prone to chatter so you'll need to be less aggressive.

Generally best to remove the compound and bolt an angle plate right to the cross slide.

The filing rest isn't a bad idea actually either. You need to make 2 side plates, 2 axles and four rollers. Clamp the plates together while drilling/reaming the axle holes and make the axles of drill rod. Flanged drill bushings make great ready made rollers, which should be hardened any way. Best way to mount is with the rear axle slightly lower so feeding the cross slide in increases depth of cut. You start with a coarse file and finish with a fine. For a one-off filing is actually quicker than setting up a machine. A simple indexing plate is easy enough to make.
 








 
Back
Top