AK drill - chuck taper - what is it?

[RedOrZed]

I've been working on restoring an old "AK" brand drill press, acquired years back from local auction.
Stripped, replaced brass cage bearings, reassembled and ran it up to drill a couple of holes, but noticed the drills run very out of round.

Dropped the quil out today, got the chuck off to find the taper is definitely not JT.

It's 0.5510" at the top , 0.5010 and the taper is 0.625 long.

The taper and the inside of the chuck are a bit bashed. The chuck doesn't fit any key from my drawer of random keys.

There is some play in the quill bushing but not a dreadful amount.

Suggestions on the taper please? Or how to fix the runout? Clean both tapers and try to hammer the chuck on square?

 

[Agroshield]

Determine where the run out is ocurring.

Turn down the existing taper to the nearest Jacobs. There is another, B-taper, used on drill chucks, so look at those also to see which series has most compatible dimensions to existing. Possibly convert to screw-on (1/2" UNF) as no taper turning required, just a square flange and a loose thread cut with a die.

 

[BrokenBiker]

B taper maybe?

 

[RedOrZed]

Cheers, doesn’t seem like B taper, not any of the even numbers anyway.

Threading seems like the best idea, thank you!

 

[BrokenBiker]

Have you determined it is actually the taper causing the run out? Both tapers could easilly be cleaned up with a small stone if the run out is just because of the damage

 

[RedOrZed]

Have you determined it is actually the taper causing the run out? Both tapers could easilly be cleaned up with a small stone if the run out is just because of the damage

No, I don't know if it's the shaft or the chuck. The correct thing to do is put the shaft on some v-blocks and find out.

I'd really like to replace the chuck with one I've actually got a key for.

 

[BrokenBiker]

No, I don't know if it's the shaft or the chuck. The correct thing to do is put the shaft on some v-blocks and find out.

I'd really like to replace the chuck with one I've actually got a key for.

I'd start by figuring out why it isn't running true...if the shaft is bent then changing the chuck is a waste of time.

If you have a lathe and can thread it then I'd be spending some time with a clock and measuring the whole thing