Drill Bits

[Merlin]

Not for scrolling:I know you can get large bits with smaller shanks but can you get them the other way round.

I make toy wheels with a circle cutter but at times I only need a 6mm (1/4") dia centre hole for the axle, the circle cutter has a fixed (but removable) 8mm  5/16" drill.

What I'm after is a 6mm (1/4") drill with a 8mm (5/16") shaft.

Any advise please

***Merlin***

[Rapid Roger]

I'm a drill bit freak and I've never heard of such an animal but, that is not to say they don't exist.
I use hole saws to cut wheels and there are hole saw holders that hold a 1/4" bit in the center and a hole saw cutter of any size and step up to 7/16" hex shank for the drill chuck.
I like the hole saws because I can cut most any size of circle for wheels and still maintain a 1/4" hole for the axle.
My set is rather extensive from 9/16" up to 3-1/2" in 1/16" increments for the smaller sizes and then I skip a few sizes in the upper end. They can get expensive in the larger sizes.

Rog

[Merlin]

Thanks for that Rodger, I don't do enough wheels to warrant a good set od hole saws but the circle cutter ideal for wheels and any size I need.

***Merlin***

[Paw Paw Ray]

Have you thought of using a large plug cutter?  Then you could drill any size hole you want in the middle.

[Rapid Roger]

Can you get 5/16" diameter dowel for the axles?

Rog

[EIEIO]

I have a set of drill bits that have a hex on the drive end with various sized drill bits. They fit into a hex screwdriver holder in a hand drill. Would the hex happen to fit into a 5/16 hole? Or maybe you could grind the hex a little so it will fit.

You could also look for a bushing with 8mm OD, 6mm ID and braze a 6mm bit into it. McMaster-Carr has this:
http://www.mcmaster.com/#standard-drill-bushings/=q5e05t

Or this 1/4 x 5/16 sleeve bearing:
http://www.mcmaster.com/#standard-sleeve-bearings/=q5e0xk

[Merlin]

Thanks Ray I was thinking along those lines and just about come up with the answer, bout I need someone with a metal lathe.

Rodger: I wrote the imperial and metric sizes for comparison only, I will of cause be using metric no imperial in NZ any more.


Thanks for the help guys

***Merlin***

[TheMelster]

Not for scrolling:I know you can get large bits with smaller shanks but can you get them the other way round.

I make toy wheels with a circle cutter but at times I only need a 6mm (1/4") dia centre hole for the axle, the circle cutter has a fixed (but removable) 8mm  5/16" drill.

What I'm after is a 6mm (1/4") drill with a 8mm (5/16") shaft.

Any advise please

***Merlin***

Is this what your talking about?
https://www.fastenal.com/web/products/details/0253798?searchMode=productSearch&zipcode=&filterByStore=&filterByVendingMachine=&productSearchQueryString=term%3D0253798%26searchMode%3D

[Merlin]

Melster: Along that line but I think it probably be easier to make one than import cause I can't find one in NZ.
Thanks for the info.

***Merlin***