Metal cutting blades, mini cut off saw.

[Jon Murphy]

I am normally on the Wood Turner's forum but it seems to me this one is the best for my question. I am going to ask about the blades for a mini cut-off saw for cutting metal alloys.

I have a Proxxon mini miter saw, the rpm is 5400 (no load) and the blade diameter is 3 1/4". I make my own hollowing tools for my wood turnings, and have to cut shafts from O-1 steel and cutter bars from 10% cobalt HSS. Working with the thinner shafts and cutters (1/2" round shaft, 3/16" square cutter bar) I have no problem - but I'm chewing up the aluminum oxide blades for ferrous materials. Admittedly it is my fault to some extent - if I'm cutting too thick a piece the expansion of the metal in the kerf grabs the blade and tears up the arbor hole.

What I want is a metal cutting blade that itself is metal, at least at the arbor hole - or one which cuts a wider kerf at the edge so it won't grab. My vendor has a Diamond blade, but it is listed as proper for tile, stone, etc. As that blade is $66 I don't want to buy it as an experiment unless someone here thinks it might work (if it doesn't I won't blame you, just want your thoughts).

It seems to me that my mini cut-off saw should be able to cut through anything it can hold - as long as the width of the cutting edge of the blade makes a kerf wider than the blade so that the rest of the blade isn't rubbing on the workpiece. BTW, my arbor is 10mm.

Best, Jon

[Bruce Page]

Jon, I don’t think a diamond blade would work unless you were flooding the cut with water, and even then I would fear that it would quickly load up and stop cutting. I don’t know of any better alternative to the aluminum oxide abrasive disk for cutting ferrous materials. 5400 rpm would be much too fast for any toothed blade that I’m aware of.
IMO, the 3 1/4” abrasive disk is too delicate for what you want to cut. Your best option might be to get a larger chop saw with a thicker, more durable disk. I’m not a fan of Harbor Freight but they have several chop saws at very reasonable prices.

[raul segura]

I know we are always looking at accuracy, but if you just want to chop .. . and grind later any way. Id just get a cheep, cheep 4.5" angle grinder. Pick up a ten pack of thin 4.5 cut off wheels from Harbor freight easy $ and excellent. Go easy on the the tool and it'll cut like hard butter. Id also picked up some leather sleeves under 10 bucks "fiberglass particles in skin " and or gloves if you like. You can get very good cuts with a little practice. If you go this way ... .. . definitely hold parts in a vice a heavy one if you have, or the blade will bounce around in the cut and Frey very quickly (like your oxide blades ). I don't know how accurate your machine is $ But if there is any play in the hinging part or play in the shaft at deeper cuts it may grab the sides and eat up the blades just like holding by hand. They also make a 45$ part that can hold a grinder like a chop saw but you loose another quarter inch of blade depth. 60 bucks would get you two angle grinders and a 10 pack of blades.

[Jon Murphy]

Bruce and Raul, good answers gents.

I do have a Harbor Freight 6" cut-off saw, and use both 6" and 4 1/2" blades on it. BTW, I concur on not being a great fan of Harbor Freight in general as they sell some crap - but they also sell some darn good stuff at low prices. I'm lucky enough to have a retail store a half hour's drive away so I can look at the tool before buying it. I also have an angle grinder, a Rotozip, but can't control it for the small work, I'll have to look into the leather sleeves Raul mentions - but I don't quite understand what they are. I'm guessing that they are slipped over the workpiece and act as a guide as they are cut through with the work piece.

The problem with my HF cut-off saw is the clamp/vise - it provides no support for a short piece as it is a single centered screw and the clamp face turns. But when one gets good answers one can often think of alternate solutions. I'm thinking that I could V groove pieces of wood to hold my 1/4" square cutter blanks, or the round shaft blanks and clamp them into the HF cut-off saw. Cut through the wood and the metal blank together - then there is no unsupported end. I think it will work.

Best, Jon