Woodworking Mitre Saw into Metal Cutoff???????

[Sir Stinkalot]

Ok …. why cant this be done? …. I know it most likely cant but I would like to know for sure.

I quite enjoy getting away from the timber and venturing into steel and the welder ….. I am looking at picking up a cheap cut off saw to be a little more accurate in my cuts …. as it will only get minimal use I do not wish to spend more than $100-$150. I would like to be able to tilt the saw 45deg. from the vertical as you can do with the woodworking mitre saw. From my limited understanding of cut off saws this cannot be done … so here is the question …. why cant I fit a metal cut off blade to my woodworking mitre saw? Keeping in mind that the mitre saw that I currently have is the cheap $100 GMC that has a very small blade. I understand that the metal dust wouldn’t be good for when I set it up for woodworking again but I would be sure to clean it well after each use. If this works I will end up buying a better quality sliding mitre saw in the future and leaving the metal blade in the GMC permanently.

Thanks

Stinky.

[barnsey]

Sir,

My use of cutoff saws has been that the table clamp usually has the ability to clamp the work at an angle rather than tilting the saw. Don't know if a cheapie will have that ability but with your ingenuity you could probably make it work.

I've only used metal cut off blades in my 9 1/4" pentagon worked like a charm cladding the carport some time back otherwise the 4'' angle grinder does the job and I've seen some fixtures for mounting them for cutoff. Guess it depends on the stock you want to cut and how often.

Jamie

[Breaker]

If your saw has bush bearings. It will not last long with metal fillings. :mad:
Metal fillings cut out bush bearings very quickly and there is extra weight/ virbration on bearings cutting metal. You may get some life out of a sealed bearing unit but it is likely the bearings would be much lighter than a product designed for the job.:confused:

[Sir Stinkalot]

Thanks Jamie,

The angle of cut will need to be 45 deg from the saw vertical not 45deg to the horizontal. I hope the attached sketch will help. The reason that I need this is so I can bend the seel around to make a 90 deg corner that has one face continuous which makes it alot cleaner. I could cut the two pieces through at 45 deg and join them but it would have an ugly corner. I have tried the angle grinder with appropriate disk but it is slow and difficult to maintain the 45 deg. angle I was also after something that would produce a flat cut at 90 deg to the piece which is also difficult with the angle grinder.

Breaker,
I understand that it wouldn't be as good as a unit designed to do the job but it would be for very light usage, 15-20 cuts each year, and the metal is light guage only about 2-3mm. I would guess that a $100 GMC would have bruch bearings ... or the cheapest bearings that they can find.

Stinky

[Breaker]

There are metal devices for mounting an angle grinder to make neat angle cuts which are less than $100. 4" one costs about $30.00. Larger unit for 9" is about $60. SupaCheap?

[Sir Stinkalot]

Any idea where? I have a 100mm angle grinder.
The only real limiting factor then is the width of cut.

[Breaker]

SupaCheap had then in S.A.. Tool places that have angle grinder, may be Bunnings, larger Mitre 10, HomeHardware ????:confused:
Have seen at various locations in S.A. especially the 4". The cut is the thickness of the disc.

[Glen Bridger]

Hi,

The problem I see trying to cut metal on an angle like this is the abrasive disc would tend to slide across the surface a little bit which wouldn't give you a neat cut. Kinda defeats the desired result. If this happens it would put extra stress on the disc and its not fun when/if one breaks apart while its spinning around.
Most saws should have an adjustable vice anyway.

Glen

[Sturdee]

Two years ago my old Black & Decker 8" mitre saw was no longer good enough for woodworking ( sawguard would not retract properly and new blade was impossible to get ) so I converted it to a metal cut of saw.

I took out the guard and fitted a cut of blade and works like a charm.

It gets about the same useage as you would want to do.

Peter.

[Sturdee]

Whilst in the workshop I tried to do the cuts you want to do as normally I only use it for normal cuts.

1st problem - cut of wheel was worn down and to short to cut at 45 deg - the solution was to put a timber ofcut on base and clamp a spacer block to fence and it worked okay but boy did it stink as I cut into the wood. ( maybe you would feel at home with the smell )

2nd problem - as your cutoff wheel wears down the width of metal you can cut reduces unless you use a sliding mitre saw.

Hope this helps.

Peter

[Sir Stinkalot]

Thanks Peter,

I thought that might be the case with the disk wearing down. As it wouldn't get much use there shouldn't be much of a problem, the way that I look at it is I would have to outlay $100+ for a dedicated cut off saw with one disk that doesn't produce the cut that I need so if I have to go through a few extra disks so be it. I know the 100mm disks for the angle grinder are about $3 each .... what price are the larger ones?

Thanks

Stinky

I love the smell of buring timber in the morning.

[Sturdee]

Stinky

I bought some 100mm disk for my angle grinder from Clints last saturday - packet of 5 for $ 1.99 . Don't know the cost of the large wheels as the last one was bought some time ago. I'll check next time i'm in Bunnies.

Peter.

[Dan]

Might be worth checking the RPM of wood Vs metal machines. At a guess I'd say you're safe but check anyway.

And also, what Glen said, cutoff wheels are pretty fragile and would prefer starting the cut perdendicular to the material, if comming in from an angle be very gentle until the disk has made its way in a few mm.

[arose62]

Seems to me that you'd have major problems trying to get the depth of cut consistent enough to make a nice clean exterior surface. I know my SCMS has a "depth-stop" which is wildly ambitious in design. It will consistently bring the saw blade to a stop within 1 inch-or-so of the same depth repeatedly. Other saw makes/models may vary.

Some thoughts:

1: can you get a profiled grinding wheel ? One that has a V-shaped outer edge? This would let you cut a V-shaped groove with the cutting wheel held vertically.
1:a: can you shape a grinding wheel to have this profile ?

2: if it's light gauge metal, and you don't make many cuts per year, could you sacrifice a router cutter ? They do make V-groove cutters which would let you achieve the sort of result I think you're after. (Not sure I endorse this idea)

3: can you purchase a cutter designed to do this cut in metal ? Perhaps mount it in a drill press ?

4: does it matter if you cut a square groove, rather than a V-shaped one ? You'd still get a clean outer face when you bent it. This technique is used to bend wood to varying radii.

5: can you use a shaped grinding stone, in one of those hand-held Dremel-type thingys?

Cheers,
Andrew

[Sir Stinkalot]

Thanks for all of the replies so far ..... I will try to clear up what sort of cut that I am attempting.....

The steel is (without checking) 45x19mm. I start with the 19mm side facing up .... I mark the center line of the corner that I want to create (the orange line) .... then I draw two line at 45deg from here. The next image shows the stock on the saw with the 45mm surface facing up .... I then square off the two 45deg lines onto this face. The cut is then made at a saw angle of 45deg back towards the orange line, the cut does not go through to the face marked b it stops just short. After the two cuts are made then there is a triangle of waste material removed. The stock is then bent so the two cuts meet. As you can see in the plan the two faces (a) are now at 90deg to each other, the face (b) bends around to create a seamless edge. If the two 45deg faces do not meet correctly that is fine as this is where the welding happens so when they are welded up I simply run the angle grinder over again and then they appear seamless also. I hope this helps and shows why the blade needs to tilt 45deg not the table.

Stinky.