Wrecked Aluminium from chopsaw

[Mr V]

Personally I prefer the horizontal band saw for cutting stock. They include a vise to clamp the material and hands never have to be anywhere near the blade. Not it is not as quick as a chop saw but with the right blade it goes pretty quickly. Since we got ours the chop saw is only used for wood.

[StillDefective]

Why has no one said anything along the lines of: the blade is wrong?...

I am almost positive that is a wood blade, the teeth are spaced out FAR too much and have the end bits on them. The huge teeth grabbed the part (ESPECIALLY since it is a tube) and threw it. This is an extremely obvious safety hazard to me. I have cut more aluminum on a compound miter saw WITH THE CORRECT BLADE then I wish to count. It is extremely safe. One hand has to be on the trigger and pulling the blade down, and the other is free, but it is VERY obvious where the blade will go, especially with a laser, and I use the other hand to brace the part if needed.

[Tungrus]

Are you sure the blade in the original post photo is for metal? Looks like its for wood. please don't try wood saws for cutting metal!

[StillDefective]

Originally Posted by Tungrus

Are you sure the blade in the original post photo is for metal? Looks like its for wood. please don't try wood saws for cutting metal!

Hah I beat you to that by about 11 minutes.

[asid61]

We use a metal cutting chop saw; a Dewalt. We cut aluminum extrusions including 2x1 and bosch without problem. It has a clamp onboard, so the material does not lift or move around.
We had a problem this year with a terrible cut (nobody got hurt or was in danger) when somebody tried to cut 1/8" aluminum at an angle. Bad idea, and the piece had to be scrapped. We use a bandsaw for plate now.
The clamp is hard to get square and the saw is extremely loud, but in my two years on the team nobody has gotten hurt or even come close. Clamping correctly makes things much easier.

[magnets]

Looks a lot like an aluminum blade to me.

http://www.amazon.com/Freud-LU89M010...freud+aluminum

[CENTURION]

We've been using a wood chop saw to cut tubing, C-channel, and 80/20 for the entire time I've been in FIRST (five years I think? something like that).

But we have rules about how to use it:

Always use a secondary clamp (We use a C-clamp), make sure the part is clamped in a way where it's physically restrained (If you've got a 1x2 bar, the 2" side should be against the fence, where the clamp is putting pressure).

Your hand that's not on the handle should be at your side, or behind your back. No need for it to be anywhere near the cutting area.

Go slow, let the saw do the cutting. It should take 3-5 seconds to get through a 1010 bar of 80/20. (You can actually go a fair bit faster, but this is a good range for students, because if the accidentally go a little too fast, it's not an issue)

Bring the blade all the way down, turn it off, and don't bring it up until it's stopped spinning.

And of course, make sure you've got a proper blade for aluminum. Honestly I forget the tooth count on ours, but it's a tri-chip blade, I'd guess it's an 80-tooth.

As far as I know, we've only had one accident with that saw, and that was one time long ago where I brought it up while still under power. Either the bar expanded from heat, or slipped in it's clamp, and it caught the back edge of a carbide tooth. It broke three teeth off, and threw them at me. Luckily I was okay, they didn't even get through my shirt.

So one minor accident over five years and thousands of cuts, and that due to improper use. We've never had any issues from people using the above rules.

[Oblarg]

I've seen aluminum scrap ejected from a chop saw before, but I've never seen it result in injury and it never happens if you have the work piece properly clamped and you are firm and steady while cutting.

As a rule, neither 449 nor 4464 allows freshman to use the chop saw at all. Older students must have a mentor immediately present and observing. Work pieces must be clamped on both sides if possible (we just use normal c-clamps), and if it is impossible to clamp either side then a mentor must make the cut.

We have not had any safety incidents of note involving the chop saw on either team, and neither team could function without regularly using a chop saw for aluminum tube.

Remember to replace your chop saw blade regularly if it sees heavy use - the teeth do wear down, and once you lose a couple of those you can start having problems.

Originally Posted by CENTURION

Bring the blade all the way down, turn it off, and don't bring it up until it's stopped spinning.

This is absolutely crucial. Even a clamped piece can settle slightly once the cut is made, and bringing a spinning blade back up into a piece that has moved even slightly is a bad idea.

[CENTURION]

Originally Posted by Oblarg

[snip] Work pieces must be clamped on both sides if possible (we just use normal c-clamps), and if it is impossible to clamp either side then a mentor must make the cut.
[snip]

Usually clamping on both sides of the blade is considered to be a very bad idea (Blade binding and all that). We have had no problems clamping with the built-in clam and a C-clamp on one side.

If you follow the "Don't bring the blade up until it stops" rule, then I don't think clamping on both sides is an issue, but I would still stick to the one side.

I always try to remember that these are skills that the students will take with them, beyond my or any mentor's guidance. And in recognition of that, I try to avoid teaching the students things like this. That is; procedures that are unsafe, and only become safe under a narrow set of circumstances.

For instance, if the student is cutting a different material, where you can raise the blade under power, and they still clamp both sides, then something bad could happen.

[Oblarg]

Originally Posted by CENTURION

Usually clamping on both sides of the blade is considered to be a very bad idea (Blade binding and all that). We have had no problems clamping with the built-in clam and a C-clamp on one side.

If you follow the "Don't bring the blade up until it stops" rule, then I don't think clamping on both sides is an issue, but I would still stick to the one side.

I've never had any issue with it at all (been doing it for ~7 years now), and it does a great job of ensuring that your work piece stays right where you want it.

We never let the students bring the blade up while spinning regardless of material; we find it better to keep the procedure the same.

[CENTURION]

Originally Posted by Oblarg

I've never had any issue with it at all (been doing it for ~7 years now), and it does a great job of ensuring that your work piece stays right where you want it.

We never let the students bring the blade up while spinning regardless of material; we find it better to keep the procedure the same.

I'm sure you haven't, but that's not really what I was getting at.

One thing our shop mentorship identified and focused on is consistency. Because we all, as experienced metalworkers (Some professionals, some amateurs) have different ways of doing things. And those methods are safe on their own. But, if you mix-and-match different parts of them, somebody could definitely get hurt.

So before doing any safety training this last year, we sat down and laid out exactly what method we were going to teach the students, and we tried to ensure it was the method that follows "best practices" or at least general widely-followed practices. That way, if our students go on into machining, like I did, they won't have to un-learn anything we taught. And we don't have to worry about them accidentally mixing-and-matching our methods, and those that are used out in industry/education.

I mean I don't want to tell you how to mentor or anything, just my $0.02.

[ChuckDickerson]

Originally Posted by CENTURION

So before doing any safety training this last year, we sat down and laid out exactly what method we were going to teach the students, and we tried to ensure it was the method that follows "best practices" or at least general widely-followed practices. That way, if our students go on into machining, like I did, they won't have to un-learn anything we taught. And we don't have to worry about them accidentally mixing-and-matching our methods, and those that are used out in industry/education.

Did you by chance document this in a form that you would be willing to share so that others may be able to benefit?

[CENTURION]

Originally Posted by ChuckDickerson

Did you by chance document this in a form that you would be willing to share so that others may be able to benefit?

We have a master tool and safety document from a few years back, and last year we only edited the relevant parts. This summer I want to do a full re-write, with more procedural instructions (As in; "This is step 1, this is step 2," etc). Right now it's organized more as rules, rather than a procedure. (A member from Team 1086 Blue Cheese posted this a while back, and I think it's great.)

Here's our master document.

The first 50 pages are all tool info, you can skip those

We then have the students take an online test with questions on those rules, which the have to pass with a 100% score (retakes allowed). And then we do mentor-guided hands-on training in the shop, and the student gets signed off on a list.

[RoboChair]

Here is our solution to chop saw safety.

Big piston is about 140 pounds of force, small piston is about 40 pounds. Clamp is actuated by a foot switch toggle. Anything bigger than 4" in a dimension gets cut with the band saw.
We also added a pneumatic brake to the blade, if the blade is off the solenoid fires and it pushes the side of the blade and stops it in about 2 seconds. You must depress BOTH buttons on the 2 handed handle to turn it on, both hands must be used.



The main thing I have noticed that causes parts to get ejected are small loose pieces getting snagged by the blade if it is brought up too soon. That is why we clamp both sides.

This thing has been amazing this year, 3 HP 3 phase motor. No injuries from the saw. And it only cost $95! plus some parts, but still way cheap. I love auctions.

[IndySam]

Originally Posted by RoboChair

Here is our solution to chop saw safety.

Big piston is about 140 pounds of force, small piston is about 40 pounds. Clamp is actuated by a foot switch toggle. Anything bigger than 4" in a dimension gets cut with the band saw.
We also added a pneumatic brake to the blade, if the blade is off the solenoid fires and it pushes the side of the blade and stops it in about 2 seconds. You must depress BOTH buttons on the 2 handed handle to turn it on, both hands must be used.



The main thing I have noticed that causes parts to get ejected are small loose pieces getting snagged by the blade if it is brought up too soon. That is why we clamp both sides.

This thing has been amazing this year, 3 HP 3 phase motor. No injuries form the saw. And it only cost $95! plus some parts, but still way cheap. I love auctions.

Cylinder not piston. Sigh....,,,

On the other hand. That's pretty cool.