Gun Drill Adaptation.

[niall Y]

Nor sure that this is the appropriate forum, though in its normal context, this sort of drill is used for metal working. I, however , have one I wish to use for,wood, so will be swapping out the coolant for compressed air.

I need to get a compressed air line onto the end of this drill. And am open to any suggestions as to how to do this. Hammond and Co, do sell an adaptor that fits into the Morse taper of the lathes tailstock, which in turn mates with the particular driver on the non-business end of the drill.

This particular option isn't open to me as the distance between centres on my lathe would have to be in the region of 1metre to accommodate the workpiece and the drill at commencement of the cut. So, I am going to have to use it hand held,

The obvious solution would be to enlarge the hole in the driver and fit in a 1/4" Bsp connector,but the driver is hardened steel. And I am not sure I can safely anneal it enough to drill out and tap a thread.

Any advice, or other suggestions would be welcomed

Niall


THE DRIVER IN QUESTION WHICH IS 25mm IN DIAMETER

 

[ChaiLatte]

Can you go larger than the 25mm diameter with any part of the connection?

Find some nominal 1" bore rubber hose and jubilee clip it onto the steel part.

You could buy a brass BSP connector with an inside diameter >25mm and JB Weld it on.

A more refined solution would be to turn the ID of the brass piece to 25.1mm and use loctite. This has the advantage that you can heat it up to denature the loctite in the future if the part needs removing.

If you cannot increase the OD of the part, loctite something into the hole in the hardened piece. Sure, it may restrict the airflow a little, but probably not enough to cause a problem.

 

[niall Y]

Can you go larger than the 25mm diameter with any part of the connection?

Find some nominal 1" bore rubber hose and jubilee clip it onto the steel part.

You could buy a brass BSP connector with an inside diameter >25mm and JB Weld it on.

A more refined solution would be to turn the ID of the brass piece to 25.1mm and use loctite. This has the advantage that you can heat it up to denature the loctite in the future if the part needs removing.

If you cannot increase the OD of the part, loctite something into the hole in the hardened piece. Sure, it may restrict the airflow a little, but probably not enough to cause a problem.

Thanks for the reply,
Yes, I can have it larger than the 25mm at least to something I could comfortably hold in my hand. There is an American turner demonstrating using a gun drill who has an anodised aluminium handle attached to his with a hose line fixed to the end.

I haven't seen anything equivalent for sale in this country. These I believe mate with the particular driver design that allows them to clip into position. I believe mine has the European Standard fixing system.

I am already toying with your last suggestion, which in my case would to be to use a 1/8" BSP airline connector into the end of the driver, either epoxied directly in position or into a threaded sleeve that itself can, in turn be epoxied in position.. To this end I am waiting delivery of a fitting I can experiment with.

I feel it would be better to have some form of handle - wood,metal, or plastic - that I could fasten on and remove more conveniently other than having to use heat to break a bond. - as with Loctite, or standard Araldite. Though, at the moment I can't envisage how to do this.

I have considered using some rubber hose to cobble together a fitting, but I think Jubilee connectors in this context might be a bit of a no, no, as they might damage ones hands if the drill catches and starts revolving

 

[ChaiLatte]

I feel it would be better to have some form of handle - wood,metal, or plastic - that I could fasten on...

The end of the piece in the photo seems to have a flat milled on it. A grubscrew could secure a handle to that.

You could incorporate an O-ring into the handle to provide an air seal (that may also need PTFE tape on the grubscrew to stop it leaking).

A wooden handle with a threaded insert for the grubscrew would look quite classy as you could carve some hand grips in it after it is turned (saturate the BSP threads with superglue to strengthen them).