Cutting aluminum with the Kapex 60

[dellato]

Hi !
I'd like to have your opinion about this problem with my Kapex 60 (or more likely : a problem with my technique  [wink]).
The reason I bought the saw is for sawing wood.  And for that the saw excels with perfectly square (or angular) cuts.  But sometimes, for example when making a jig, I'd like to cut some aluminum profiles (nothing fancy, just like a simple flat one, or a V- or U-profile). To do so, I bought the dedicated aluminum/plastics Festool saw blade.  Now, why is it that every time I want to cut the aluminum with it, the cut results in strong kickback, bending the aluminum (please, see attached image).
It happens every time.  I haven't been able to make a single clean cut.  Now, I'm actually scared to try it again, as I don't want to damage the saw, or get it misaligned.  I've done this probably hundreds of times on my previous miter saws without any problems but on the Kapex I somehow can't do it.  I've even searched YouTube and this and other forums to see if I can find anything particular that I'm (not) doing that makes this happen, but can't find anything.  I contacted Festool Belgium through their contact form but didn't get a reply (yet?).
I set the saw to speed 1 (also tried higher speed) and gently push the saw down.  The profiles are firmly clamped.  The mentioned alu/plastics blade is brand new and shows no visible defects.
I really hope you guys can help me getting this right.  Thanks heaps in advance !

 

[tjbnwi]

The blade has a negative hook. Place a piece of wood against the fence that places the center of the aluminum under the centerline of the blade. Lock the slide use the saw as a chop saw. Use two sided tape to hold the wood in place. Set the speed to 3.

Tom

 

[Crazyraceguy]

I cut aluminum all the time, different saw, but that's not the issue here. The solution is technique.
Support of the piece is key and the gap through the fence is too big. Make yourself a wooden tray with a back that stands vertically.
Also, you mentioned that you clamped the piece into the saw, but clamping a piece of scrap wood on top can help even more. Get it close to the cut, the idea is to never allow the saw to bend/move the piece.
There is also orientation. The pic you posted looks like 1/8" x 1" (or similar) the cut will probably be better if you lay it flat, rather than standing up, but it's worth experimenting. I never use a physical clamp, just my hand, holding the metal trapped under the scrap, either down, or back, depending on the profile.
You could also be cutting too slowly. Don't "mess around" with it, but don't go crazy "hacking at it" either.
Stop the saw at the bottom of the cut, pulling out after.
The other consideration is the off-cut. tiny pieces are not good. They will catch and fly occasionally, but that's mostly about the gap. Zero clearance is your friend.
Hope this helps.

 

[AstroKeith]

I have the Apex 60 and occasionally cut aluminium and plastic trim.

As Tom says, its essential to bring the workpiece around 40 - 50mm in front of the fence, otherwise the blade will be lifting the workpiece.

I usually just hold a piece of 50x50mm softwood behind the workpiece and chop down. You won't be going all the way through the wood, so it gets re-used.

 

[dellato]

Thanks for the replies, guys! Much appreciated!
I'll give it go as soon as possible, and will report back on how it went.
The tip about using the Kapex as a chop saw rather than a sliding miter saw explains a lot, as a non-sliding saw's what I had before.
The aluminum in the pic is indeed about 1" by 1/8" but it was cut horizontally, not vertically.

 

[Michael Kellough]

If you chop, stand the stock up against the fence.

If you slide clamp the stock down on the table and maybe put some wood on top, or slide a little slower.

It’s also helpful to put some kind of lubricant the aluminum. WD-40 or even denatured alcohol, especially if you slide slowly.

 

[rst]

As part of the commercial glazing trade, I've cut thousands of feet of aluminum in the past 50 years. 45 years ago we used a plywood blade installed backwards and grease sticks.  For most recent times, 35 years, I used aluminum/plastic blades and lube with either WD-40 or Tap Magic.  Our fab shop has upgraded to a #6000.00 16" pneumatic saw and automatic positioner.  Can't remember what the fluid mix with water they are using now, probably a generic milling additive.  As mentioned above, proper support is mandatory and with really thin material we used a thin plywood or MDF on top to trap the job between. 

 

[Cheese]

On both my cut-off saw and my cold saw, the rear fence is moveable to allow the center of the piece being cut to align with the center of the blade.

On the Kapex, you need to do as Tom suggested and use a shim to position the part to be cut at the center of the saw blade.

When cutting thin stock per your example, I cut the stuff lying flat on the table. For channels or angles, I cut the stuff with the legs pointing down, resting on the table.

I also use these wax sticks to lubricate the cut, help prevent heat buildup and lessen the likelihood of aluminum chips "welding" themselves to the teeth of the blade.

Chop only...do not slide cut.

[attachimg=1]

[attachimg=2]

 

[Crazyraceguy]

If you chop, stand the stock up against the fence.

If you slide clamp the stock down on the table and maybe put some wood on top, or slide a little slower.

It’s also helpful to put some kind of lubricant the aluminum. WD-40 or even denatured alcohol, especially if you slide slowly.

When I was in a vocational school machine shop(many years ago) they taught us that denatured alcohol was the best thing for aluminum. Of course this was before "Tap Magic" or anything more specialized was put into use. The main point was no oil
What's that other stuff? A9? something like that. It's more of a paste type stuff, supposed to be ok, but I have never tried it myself.

 

[dellato]

Thanks for all the further tips !
Can't seem to find the Tapmatic nor Milwaukee lubricants here (I'm in Belgium).  But I did find a Trend wax stick on Amazon which seems to be very similar and is especially recommended for aluminum : Trendiwax.
I'll order it and try it out as well.

 

[tjbnwi]

WD-40 is all you need when working with aluminum.

Tom

 

[bidn]

Thanks for all the further tips !
Can't seem to find the Tapmatic nor Milwaukee lubricants here (I'm in Belgium).  But I did find a Trend wax stick on Amazon which seems to be very similar and is especially recommended for aluminum : Trendiwax.
I'll order it and try it out as well.

Thank you, very good this Trend wax stick! I ordered it too.

Would you need a small stick. e.g. for put on the piece you are going to cut, there is this small one :https://www.amazon.de/gp/product/B0076V46VK/

 

[bidn]

WD-40 is all you need when working with aluminum.

Maybe in the USA, but I understood WD40 would not have the same composition in the EU (probably due to some regulation), here it is mainly a petroleum ether solvent aimed at removing dust or rust on stuck pieces to unblock them (definitely useful), it might contain some lubricant too but it is not a grease for metal cutting or drilling.

Also I think it is better to apply a paste onto the sawblade because the large diameter of the saw blade combined with the high speed (strong centrifuge force) would not keep a fluid like WD 40 in place but would project it away.

 

[tjbnwi]

WD-40 is all you need when working with aluminum.

Maybe in the USA, but I understood WD40 would not have the same composition in the EU (probably due to some regulation), here it is mainly a petroleum ether solvent aimed at removing dust or rust on stuck pieces to unblock them (definitely useful), it might contain some lubricant too but it is not a grease for metal cutting or drilling.

Also I think it is better to apply a paste onto the sawblade because the large diameter of the saw blade combined with the high speed (strong centrifuge force) would not keep a fluid like WD 40 in place but would project it away.

I did not know the chemical composition of WD-40 is different in the EU. The go to for aluminum at one time was kerosene. Seeing as all he is doing is cutting simple vegetable from the kitchen will work well. 

As for it projecting off the blade, the WD-40 is not applied to the blade, it is applied to the work piece. We can get WD-40 in gallon cans here, it is applied with an acid/flux brush or spray bottle.

Tom

 

[rst]

I buy WD-40 in gallons and put in spray bottles, give the saw switch a poke, give the blade tips a quick squirt. If I’m cutting a lot, I cut a piece scrape brass hardware to clean the galled aluminum off the teeth.

 

[dellato]

Yes, WD40 here definitely is more like a release agent than a lubricant.
I also have special fluid for assisting with cutting threads in steel. Maybe that would work? On the other hand, having to spray it on the workpiece - and thus on the saw bed - worries me a bit. Getting oil or oily substances there perhaps might make it on the surface of wood cut after the aluminum, making it more difficult to finish with stains, etc.?

 

[tjbnwi]

Honestly, the 1x1/8 you need to cut I would even bother with any lubricant. We have to cut 17mm x 4mm channel about 10 pieces once a month, I don’t change the blade from the 80 tooth wood or use a lubricant.

Use a small brush and just brush a little vegetable oil on the piece at the cut line. If you’re concerned about oil on the bed install a sacrificial bed or cover the bed with packaging tape.

Tom

 

[Cheese]

Yes, WD40 here definitely is more like a release agent than a lubricant.
I also have special fluid for assisting with cutting threads in steel. Maybe that would work? On the other hand, having to spray it on the workpiece - and thus on the saw bed - worries me a bit. Getting oil or oily substances there perhaps might make it on the surface of wood cut after the aluminum, making it more difficult to finish with stains, etc.?

If you have a dedicated chop saw then WD40 works great but for a saw that will see use on aluminum & wood, I'd stick to a dry lubricant like the white wax sticks I recommended. The wax really stays on the blade and doesn't migrate so it's easier to clean up when the saw is needed for wood working.

 

[dellato]

I first had to finish an urgent project, but finally got around to trying to cut the aluminum, taking into account all the tips you guys provided.  And the result is : it went flawlessly.  [smile]
I decided to try and cut the same simple flat piece of aluminum as the one in the picture from my original post, just to compare.
I made a thick 'fence' from some scrap MDF, placed the flat bar so it stood up against it and was right under the center of the saw blade.  I locked the saw so it couldn't slide and the blade was just able to pass through the opening in the fence (zero clearance).
I coated the teeth of the saw with the Trendiwax (which I'd ordered after all and had meanwhile arrived), set the speed of the Kapex to 3 and pushed down, not too slow, not too fast.  I went through like butter (see picture -- I know, there was a bit too much wax  [wink]).
Will do some more trials with U- and V-profiles (which I actually do need to cut soon) but it seems all's going well now.  Thanks to you ! Much obliged !

 

[mino]

...
If you have a dedicated chop saw then WD40 works great but for a saw that will see use on aluminum & wood, I'd stick to a dry lubricant like the white wax sticks I recommended. The wax really stays on the blade and doesn't migrate so it's easier to clean up when the saw is needed for wood working.

This. One wants a dedicated chop saw for aluminum (and other metals/dirty work) if needed with any kind of frequency.

Getting a Makita LS1040 for $200/€200 and using it exclusively for aluminum blade plus some steel dry cutting good for measure is the way to go. Sure, the Kapex can do it. But to me it is like using that Porsche cabrio to haul your furniture.

Mentioning the LS1040 specifically as it is an "older" design, rough as they come, and has the lower 4200 rpm which works great for metal cutting. We even use it with 8" blades to further reduce the linear speed at the cut point.