Wrecked Aluminium from chopsaw

[Cory]

Originally Posted by Dale

The best $1K I ever spent was when we moved from using a chop saw with aluminum blade to a cold saw. Besides the piece of mind of knowing students fingers are likely to stay attached, the noise is vastly less. Cold saws just turn at around 100 rpm so the difference is night and day. Ours is this one from Jet.

If your cold saw is running at around 100 RPM it is likely a cold saw for ferrous material.

Non ferrous cold saws are up in the 2000-3000 RPM range

[snoman]

Get a cheap band saw

http://www.cpojettools.com/jet-41445...zSQpHi5_B_CJk8

[RoboChair]

Originally Posted by snoman

Get a cheap band saw

http://www.cpojettools.com/jet-41445...zSQpHi5_B_CJk8

The whole point of the chop saw is that you don't need to mill the block to length first to make a part with it. I can hit +- 0.005" length tolerance on a run of parts with my chop saw and be ready to do everything else to it. 10 seconds, cut, 10 seconds, cut, repeat until done.
Just set it up right so you force everyone to use it right.

Also I really dislike JET. It starts out fine and becomes a huge hassle to maintain.

[Chak]

Originally Posted by RoboChair

Just set it up right so you force everyone to use it right.

Without your setup forcing everyone to do it right, how could someone do it right by themselves anyways? What are some examples of doing it wrong, and what would be the consequences?

[JamesCH95]

Originally Posted by Chak

Without your setup forcing everyone to do it right, how could someone do it right by themselves anyways? What are some examples of doing it wrong, and what would be the consequences?

Trip to the ER for an open fracture in your finger, missing a() finger(s), or other injury.

Material setup can vary from saw to saw. I setup a piece of angle wrong in a chop saw and received an open fracture in my left middle finger for my mistake. I used a setup recommended for a saw that was nearly the same, but not quite... Read the saw-specific manual for setup guidance and clamp everything down in some form.

[Monochron]

Originally Posted by RoboChair

The whole point of the chop saw is that you don't need to mill the block to length first to make a part with it. I can hit +- 0.005" length tolerance on a run of parts with my chop saw and be ready to do everything else to it. 10 seconds, cut, 10 seconds, cut, repeat until done.
Just set it up right so you force everyone to use it right.

Also I really dislike JET. It starts out fine and becomes a huge hassle to maintain.

Could you add some detail on how you get those tolerances? Is that with the chop saw setup you posted on the previous page? Are you using any DRO to get that tolerance?

[Steven Smith]

Originally Posted by Monochron

Could you add some detail on how you get those tolerances? Is that with the chop saw setup you posted on the previous page? Are you using any DRO to get that tolerance?

If you are doing a run of parts and use a stop block, butting your stock up to it each time before cutting, you can get very repeatable performance, and by measuring a part and adjusting the stop block, dial it in.

If there is a way to get 5 thou on a first cut though, especially on lengths exceeding my cheaper 8" calipers, I'd be all ears :0

[RoboChair]

Originally Posted by Chak

Without your setup forcing everyone to do it right, how could someone do it right by themselves anyways? What are some examples of doing it wrong, and what would be the consequences?

You need to make it mind numbingly easy to clamp your stock, we literally have to flip a switch to clamp our stock, the kids like how easy it is. But really, clamp it, Period. Holding it by hand is asking to have it catch a part. Also hold the blade down as long as it spins, Period. If you don't do those 2 things you will have it catch a part and do 2 or 3 things. 1 ruin your part, 2 ruin your blade, 3 send the part flying possibly into someone's face.

Originally Posted by Monochron

Could you add some detail on how you get those tolerances? Is that with the chop saw setup you posted on the previous page? Are you using any DRO to get that tolerance?

No, I mark the part and set up my work stop(shown in the pic) which is a 1/2-20 bolt. I take a slightly oversize cut and measure with calipers how long it actually made it. Then I use the fact that my 1/2-20 it 0.050" per revolution to fine tune the final size. This is one of the reasons I need that second clamping piston, to hold things on my work stop side of the saw. After that, cut and done, cut and done.

Originally Posted by Steven Smith

If you are doing a run of parts and use a stop block, butting your stock up to it each time before cutting, you can get very repeatable performance, and by measuring a part and adjusting the stop block, dial it in.

If there is a way to get 5 thou on a first cut though, especially on lengths exceeding my cheaper 8" calipers, I'd be all ears :0

First "cut", no. First piece, yes. You should get a bigger caliper, will not regret. But I suppose you could edge find it in a mill to measure it then trim it to final and cut the rest of the pieces.

I may have a slight obsession with my collection of calipers.
35" Vernier $150 Auction
18" Dial $180 Amazon (if you are cleaver with measuring you can get parts accurate to around 36" with these)
12" Dial $85 Amazon
6" Digital $35 Amazon
1" Vernier Mic $150 for a 0-1,1-2, 2-3, 3-4, 4-5 Starrett set from Craigslist

[asid61]

Originally Posted by RoboChair

The whole point of the chop saw is that you don't need to mill the block to length first to make a part with it. I can hit +- 0.005" length tolerance on a run of parts with my chop saw and be ready to do everything else to it. 10 seconds, cut, 10 seconds, cut, repeat until done.
Just set it up right so you force everyone to use it right.

Also I really dislike JET. It starts out fine and becomes a huge hassle to maintain.

We use Starret 24" and 36" rulers graduated in increments of 0.01" and a jeweler's loupe to cut long stock to size. The woodshop teacher/retired machinist can get it to within your +/-0.005", but I haven't found a student (myself included) that gets it that close repeatably. Usually I find myself doing a post-mill operation to get it the right size.
Do you have a picture of how you set up your work stop and such? That seems like it would be really useful to get that last bit of precision out.

On the topic at hand: I despise using the chop saw. We have one of the Dewalt ones somebody linked to early on in the thread, and "loud" doesn't begin to describe the hell-scream it emits when somebody turns it on. The ultra high rpms and plastic clamping system doesn't help its case either, although to be fair I've never had stock flip out on me. The only time I use it over the bandsaw is when I have to cut super long stock (because, as I mentioned above, I can't get it to within 0.005" on the saw alone). Having a massive floor bolted bandsaw helps.

[ratdude747]

I use a couple of the dewalt saws at work for cutting steel. I also used a similar one in High school (including on one occasion while on 1747). They work and when used for the right application can cut fast flat cuts. However, they heat the material a lot (since it's an abrasive saw) and they are loud (which isn't an issue at work since we all have earplugs in anyway).