drilling HSS

Hi

Have you thought about clamping the blade to the carrier with a back ledge for the blade to locate against - pretty sure the guillotines that we had where I worked used this principle for both metal cutting and pcbs.

Keith

Edited By mgj on 20/02/2011 19:07:51

Edited By David Colwill on 20/02/2011 23:32:52

Hi Doug

You could use a 4mm screw drill, these carbide drills are employed to remove HSS taps etc and are available in 4 mm from companies like Cromwell tools ( usual disclaimers) they are not cheap however.

Don't bond the blades as they will definitely come off if the blade gets hot. I would also advise against clamping them without some retaining method as I have experience of them coming off at high speed when core carving with a vertical spindle with major consequences.

Paul

Paul

Why should the blade get hot cutting PCBs?

I'm assuming the project is just to make a small but robust guillotine?

Neil

Doug, if you can look at my previous posts, you will see a simple way of drilling through HSS. If you can't find the post, which included a sketch, then I could re submit it if you message me. I may even have a drill. Roy M.

Its a bit late, but my Axminster 330mm blades have holes in them already.

Why not just use a dremel type disposable grinding bit? Would've been my first port of call. 

Michael W

Edited By Michael Walters on 11/11/2016 20:17:05

Paul J. If you look at my previous post, you will see that the design of the drill for HSS is based upon the screw drill. Carbide blanks are cheap on fleabay. Roy M

Roy , I make my carbide drills similar to the sandvik ones in the link here,

https://www.amazon.com/Sandvik-Coromant-Carbide-Uncoated-Straight/dp/B005FXF76Y

I use air to keep flushing out the micro chips and on the small ones under 4 mm use about 800 to 1200 rpm and hand feed normally in as ridgid as I can drill or mill. I cheat and increment the feed stop each cut about .1mm at a time.

Neil

Neil, mine are just cheap imitations! I think the cutting geometry is very similar, but I make them off-hand.Roy M.

Why not just use a dremel type disposable grinding bit? Would've been my first port of call.

I've chopped up hss with a dremel type tool as well. Mounted everything securely on the lathe for stability, started it running and used the cross slide/saddle to slowly chop through with a dremel, it was surprisingly easy and you didn't need much pressure, unlike with a carbide drill

GL