Drilling HSS

I have some blades which are too long for my power hacksaw. It crossed my mind that a carbide drill could produce a new mounting hole at the correct centres. Has anyone tried this and what was the result?

thanks

Dave

I'm sure you could use a conventional solid carbide bit, but they are rather expensive.
How about a solid carbide spotting drill which often appear on ebay at reasonable prices?

I've actually got an (out of commission) Manchester Rapidor Minor, which takes 9" blades.
I use the carbide tipped drill bits, often obtainable at model engineering shows, from the chap who demonstrates drilling files etc.
They worked fine, provided you clamp the blade tightly to a piece of sacrificial steel to save any problems when it breaks through.
I've also used conventional masonry bits, touched up to be sharp on a diamond wheel.
I found high speed, no lube, and plenty of pressure worked best, but make the sacrificial steel a reasonable size to act as a heat sink, to save melting the brazing.

Bill

I've not tried it but diamond drills for a dremel type tool are cheap enough - perhaps in a bath of coolant.
Back when i was working and had access to my surgical toys I'd have gone for a high speed carbide dental bur with coolant. they're cheap enough to sacrifice if fail. I keep meaning to set up a dental handpiece for these sorts of jobs .. not too bad a price when not worried about sterility Link

But you need to add the matching hose, foot switch and make up fittings for a workshop compressor and pressure bottle. If feeling wealthy you can even go for something like this + the handpiece and home compressor.Link

Alternatively one could simply try a blast of local heat to anneal the section you want the hole in since rarely cutting right at the end

pgk

Edited By pgk pgk on 14/06/2020 07:10:51

Is the blade actually HSS all the way through or Bi-metal in which case it should be easier to drill the softer spine.

Hi Bill

Thanks for the details of how you go about the job!

Cheers

Dave

Jason

the blade is ''all hard'' not 'bi-metal' so I don't have that option.

Cheers

Dave

PGK

Thanks for the alternative method. It did occur to me that spark erosion could also be used. If my memory serves me correctly machines to do this have been described in ME & MEW in the past.

Cheers

Dave

Simply softening the area to be drilled might well suffice? I doubt they are HSS.

I drilled one with a broken carbide end mill. I just ground a small spade end on it and pushed it through in the drill press.

Drilled an Eclipse all hard blade yesterday, used a 3.4 carbide drill but first heated the area to be drilled to cherry and let it cool, then I no problem.

Colin

.

Why ?

MichaelG.

It is unlikely that HSS will soften by just getting it to red heat and letting it cool, you may get lucky though.

Mike

I also convert HSS hacksaw blades for my Rapidor,Requiring 14 inch blades,I found at one time there were numbers of 17 inch blades on the second hand market as there few customer needing 17 inch blades,so deals could be done buying job lots,I shortened the blade then drilled the blade ,I used drills with brazed carbide tips from the chap who went around the steam fairs selling these drills ,his demo of perforating large old mt drills and old files was impressive,he was not amused when I asked why would you want a hole in a file,was it for hanging the file on a nail,he did not have a sense of humour.