Burnerd Chuck Screws

[Tractor Man]

I recently picked up Burnerd 6" low profile independent 4 jaw chuck that I plan to use on my Boxford lathe.

I only paid £6 for the chuck however there was a catch....

The chuck body and jaws are in really good condition however the previous owner has been rather 'violent' with the jaw screws. The ends of three of the screws have been broken preventing them from being tightened with a chuck key.

So the question is, does anyone know where I can find some replacements? I've had a quick google but have been unable to come up with any screws of the right size.

It seems a shame to scrap a really nice chuck just because the screws are broken

(Below is a very crude diagram showing the approximate size of the screws, I think they're an ACME thread with a 1.75mm pitch).

Thanks

 

[Shox Dr]

ebay is your friend, but you might need to wait, as new ones from the likes of rotagrip are scary

 

[Tractor Man]

Thanks Shox, I guess ebay is my best bet - just need some patience!

Just had a look and the rotagrip site, I see what you mean about scary prices

 

[madkayaker]

Can you not turn some new ones on your lathe?

 

[Shox Dr]

And they are about 25% of the list price. Rotagrip bought a lot of the PB stock when they liquidated.

 

[Shox Dr]

Can you not turn some new ones on your lathe?

Broaching the end would be expensive

 

[Tractor Man]

Had thought about turning some new ones - but like you say broaching or somehow drilling a square hole in the end could be tricky...

Although I guess I could put a hex head or similar on the end and make up a chuck key???

 

[madkayaker]

That would be my first idea seams silly spending lots of money on a part you can make

 

[Shox Dr]

you could cut the Acme thread and tap the end for a socket Cap Allen bolt, then cross drill and pin the thread to stop it moving

 

[Tractor Man]

Seems like making up some replacements is the way to go - unless some turn up cheap on ebay!

Using a cap allen bolt sounds like a really good idea - should allow for plenty of leverage to properly tighten the jaws!

 

[BrokenBiker]

could you not turn them on a lathe, and then cut one straight groove to act as the keyway? make a chuck key from an old flathead screw driver. as long as the groove is deep enough you should still get the clamping force you need

 

[DaveB]

Could you turn them down from 1/2 inch socket set short extensions ?
Would give you the preformed square holes in one end...

 

[Tractor Man]

Only concern with cutting a slot and using a flat head screwdriver as a key would be the leverage - but as you say if the groove was deep enough I guess it would be ok...

I'll have to check the thickness of some 1/2" extensions to see if they would work - although not sure how they would turn - guess some are made of stange alloys???

 

[BrokenBiker]

Only concern with cutting a slot and using a flat head screwdriver as a key would be the leverage - but as you say if the groove was deep enough I guess it would be ok

you could cut the handle off the screwdriver and weld a bar to form a t-bar. would give plenty of leverage

 

[Tractor Man]

That should work fine! - a bit like a screwdriver/wrench for a chainsaw!

 

[Pete.]

A 6" Burnerd uses a 7mm square key - I'd be tempted to either mills up four square bars and braze them into the broken screws or get four cheap 1/4" or 3/8" extensions, cut them short , mill squares on the end and braze those into the screws.

 

[DaveB]

I'll have to check the thickness of some 1/2" extensions to see if they would work - although not sure how they would turn - guess some are made of stange alloys???

I've managed to twist one or two over the years and somewhere I've got a socket turned down to get onto Mini big end nuts so I suspect most are not that hard.

 

[BrokenBiker]

That should work fine! - a bit like a screwdriver/wrench for a chainsaw!

yeah, i only have the idea because i hade to make a chuck key for a 3 jay chuck after snapping the original, and it was, for some reason, a flat head screwdriver with a t-bar handle

i have the advantage of having a full toolmakers workshop to use though

 

[Tractor Man]

Some really good ideas coming up - Thanks everyone!

I think trying to salvage the old screws would probably be less effort than turning up some new ones!

 

[BrokenBiker]

yeah. always worth a shot, and if it fails, youve only lost a broken part anyway