SENSITIVE DRILLING

I'm embarassed to be making this post but here goes. I have to drill some holes about 0.8 mm diameter through 6 mm thick brass. To accomplish this I thought a sensitive drilling attachment would be a good idea. I purchased a micro drill adaptor from Arceurotrade which looks exactly the same as in the catalogue - but I cant figure out how to use it.

The only thing I can think of is that I need to make a hollow sleeve, hold this in the drill chuck, insert the shaft of the micro drill in the sleeve and bring the whole ArcEuro bit of gear down by pressure on the knurled wheel.But if this is the case what drives the shaft of the attachment?

All advice gratefully received except how to do the job without an ArcEuro sensitive attachment

Regards, Chas

This isn't supposed to be sarcastic, only positive - ARC are extremely helpful, would not a call to them asking the process required be the easiest thing?

I can understand why you may not want to call them, I wouldn't either - but it may be the right thing - from the horse's mouth, etc 

Edited By David Standing 1 on 18/01/2019 12:48:42

Under normal circumstances, yes, but I believe ketan is in china at the moment. I don't know if they have other staff that could help.

Or read the 'How it Works' description in the 'More' tab on the  Arc web site

Edited By David Jupp on 18/01/2019 12:54:14

Andrew

I assume you have fitted a drill chuck to thetapered end.

If so you then hold the plain shank in a drill cuck or collet and feed the drill by holding the knurled ring and moving it to advance the drill bit. This is it doing a 0.3mm hole. I probably would just use my normal set up for 0.8mm

Ian at ARC is still there to call if you need help or I can video mine drilling a hole just say if it is in a drill, mill or lathe

Edited By JasonB on 18/01/2019 13:08:19

So i am sure many have used this type of chuck holder successfully, but a sensitive drilling machine is usually a vertical machine with a hand moved quill, usually through rack and pinion, by a hand wheel that gives positive feed back. That is, you can feel the force you are applying to the drill to feed it through the material being drilled. The size of the machine varies according to the maximum size of drill. Small bench machines are available which have high speed and sensitive quills to drill small holes. A standard 12 or 16mm chucked pillar drill will be capable but feedback will be less and will result in more broken drills.

You also would need to use drills ground to cut brass, not standard HSS drills for cutting steel.

Mine has an adjustable Allen Screw in the shank. If overtightened it might have caused Charles to think the whole assembly is locked together by disguising how it works.

Dave

Edited By SillyOldDuffer on 18/01/2019 15:14:07

I thought a rack type is less sensitive, more often a direct lever feed like the GHT design or the one that goes into a Myford tailstock. But then again I never bother with special drills for brass either.

.

Continue thinking that, Jason ...It's correct !!

MichaelG.

This is my version using ARCs attachment.

Mounted on a 2MT the whole bearing assembly was machined at the same setting to be concentric on the mill.

Ideal for spotting using the DRO.

Edited By Peter Spink on 18/01/2019 16:15:53

My grateful thanks to everyone who replied

The answer turns out to be exactly as given by SOD and I can now see how it is meant to work.

I just don't know how Jason B finds the time to help so many people on this forum, but it is much appreciated by me. I did buy the correct small chuck at the same time as the sensitive drill.because none of my existing chucks will hold such small drills. This was lucky because I had not realised just how tiny the correct chuck is

I shall be using the device in my Bridgeport Clone milling machine which is where I do all my accurate drilling these days

Best wishes, Chas