Drilling 8mm hole in HSS hacksaw blades

Does anyone have experience of drilling holes in HSS power hacksaw blades? I've found some "advice" online but I'd like to hear your suggestions specifically if you can suggest an economical drill / cutter that could be used to perform this task. It's an economy measure as I can purchase long blades more cheaply than short, but in truth one blade tends to last me forever unless a mistake is made.

I now have my Q&S hacksaw working and the existing blade holders need modding / improving / remaking so I'm trying to decide on the blades first. I did a couple of test cuts in scrap for the first time this evening using an old (slighly blunt) blade and things worked quite well.

I would compress it between two bits of thin hard wood and use a sharpened masonery drill at high speed

You must drill a hole without introducing cracks/weaknesses, the hole may need to be reinforced/stabilised

Only tried it once as an experiment and failed miserably, the hole part fell to bits

A drilling holes in glass approach is the one I would start with

Edited By Ady1 on 05/12/2020 23:30:55

Make a spark eroder?

I normally drill mine 5 or 6mm, rather than 8mm.
My Manchester Rapidor Minor takes 9" blades, so I shorten what's available; the short remains make useful scrapers etc.

I use one of the drills out of a set bought at a model engineering show many years ago.
They look a bit like masonry drills, and are often demonstrated at autojumbles, and car shows, by a chap who drills holes in files and bearings; he also sells aluminium "solder".

I clamp the blade, closely and tightly, to a piece of sacrificial mild steel using a toolmakers clamp next to where I want the hole. One jaw of the clamp is then held in the drill/machine vice.

Quite a lot of pressure and fairly high speed, to generate a good deal of heat, but not enough to melt the brazing on the tip.
If the sacrificial steel bar is fairly thick, it does help everything getting just too hot, you're looking for localised heating at the cutting edge of the drill; I might try a copper bar one day.

On a smaller scale, for a 9" hand hacksaw frame I bought recently, I use a PCB solid carbide drill, again with a sacrificial backing piece, running in a high speed Meddings bench drill; they are available in sets, cheaply off ebay.

Bill

You could use a Dremel type of tool with a cheap diamond cutter to grind your way through or maybe a diamond core-drill like these here

Martin.

Blow a hole with the arc welder (plasma would be even better). Grind off the snots with an angle grinder - linishing disc.

Tidy the hole (if it needs it) with a Dremel or a die grinder. They sell little cylindrical stones for sharpening chainsaws which are just the very thing.

Enjoy!

You could try a carbide slot drill. Cheap as chips off Aliexpress and amazingly good quality. I've been getting all my milling cutters off Aliexpress for the past couple of years and haven't had a bad one yet. And they only cost a few dollars each. They seem to be proper industrial quality kit that the Chinese use in their own factories, not second-rate "hobby" grade junk. I figure the Chinese must use milling cutters by the literal millions in all those factories over there and they are not stopping their production machinery every five minutes to change junk cutters. Sometimes their terminology is a bit off so you might have to search for something like carbide 2 flute milling cutter or something like that. There's plenty to choose from so you should find something to suit your needs.

Edited By Hopper on 06/12/2020 00:41:42

A diamond glass drill will do the job. Or a tile drill.

Steve.

Try an ordinary drill run slow with a LOT of pressure. If it's a bimetal blade I think only the strip where the teeth is is HSS? So if you drill behind that it should be softer anyway.

Somewhere is Guy Lautard's MBR books he described a drill gadget that looks a bit like a g clamp with a thrust bearing that allows the screw to apply loads of pressure to a drill chuck that's powered by an ordinary pistol drill attached to the shaft. Apparently a guy was hawking these around the USA and no one believed his claims until he rocked up at their workshop, asked them to choose their toughest and hardest bit of steel and proceeded to drill through it with an ordinary HSS drill.

Found it (from an earlier post.

http://web.archive.org/web/20040216050451/lautard.com/cole.htm

http://web.archive.org/web/20040216050451/lautard.com/cole.htm

Edited By John Haine on 06/12/2020 09:38:53

Normally the saw blade in the hacksaw is mounted with tension force. Steel is hard enough in tension force. On my self build hack saw i had the same problem. I had a professional thick expensive blade, but i want to use the same blade as in hand saws. They are thinner and cheaper. My layout is for 200mm blades the hand saw blades are 300 mm long. So i had to add a bore hole and shorten the blade. My setup was then, mark the hole heat it up with a burner to red glowing very locally and let it cool down. It was then easy to cut and boring the hole was no problem. The cutting teeeths near this area are not used and so it is no problem. This is easy to make and i never had aproblem with that.

Werner

Edited By Werner Schleidt on 06/12/2020 10:17:49

That cole drill system is actually a whole new ballgame because of its ability to punch holes with ordinary toolbits into exceptionally difficult jobs

Drill a hole through a HSS toolbit with a cheap drill...?

(Must investigate further)

The Eclipse HiCut blades that I use in my Rapidor are bi-metal so the main part of the blade can be drilled by a normal drill.

That would be yet-another-project to add to the list. I'm hoping for a quick and simple option.

That is interesting and just the information I was hoping for. Thank you very much.

I excel at blowing holes through thin section material with an arc welder...

Thanks - another suggestion worth a try.

All my old blades still have some life left in them. I'll see if they have any snapped blades at work to try this out.

If anyone is interested, this is the Q&S hacksaw and a video showing cutting with an old blade.

I have a Cole drill. Anyone who wants to experiment with it is welcome to come to Illinois and try it out.