Cutting Metal on a Miter Saw

Today, I tried out a couple metal-cutting blades on my not-designed-to-cut-metal chop saw. I neither expect to nor recommend doing this often. My online searches resulted in the general consensus that it's a bad idea for the following reasons

• metal chop saws are designed with lower RPM and higher torque, meaning that wood chop saws may have a tendency to burn out quickly if used for cutting metal
• metal chop saws are designed with enclosed motors to prevent the fine dust of metal cutting to get into the motor
• if you cut metal where you cut wood, there's a good chance of igniting a sawdust pile with an errant spark
• metal chop saws have built in clamping systems

Here are some links if you're interested:

• https://home.howstuffworks.com/what-type-of-circular-saw-blade-do-i-need-to-cut-metal.htm?fbclid=IwAR22BJeRV6iWMhz8FXtvIYNu2PZrE9yU3L3DSRe5Lfub5BueTLWXcnPrMNM
• https://forum.millerwelds.com/forum/welding-discussions/7868-chop-saw-versus-miter-saw-with-metal-blade
• https://www.finehomebuilding.com/2012/08/22/circular-saws-sidewinder-vs-worm-drive
• https://weldingweb.com/showthread.php?34466-Can-my-Mitre-saw-be-used-as-a-Metal-Cutting-Saw
• https://youtu.be/nXLW7Wew6Fk
• https://www.youtube.com/watch?v=X7VL4NIpWmM
• https://www.youtube.com/watch?v=UGvexh3-HL8
• https://www.youtube.com/watch?v=Y9oTzK1E0c8

With these considerations in mind, I still elected to give it a try. Notably, if this is something that I begin to do with greater frequency, I'll find another option. For infrequent use, though, it seems to function just fine.

On the way home the other day, I picked up two 10" blades at Lowe's: an abrasive blade and a carbide-toothed steel blade for cutting metal. Lowe's was my third stop, and the steel blade was not cheap, but it's what I was looking for.

I did some more poking around online and learned of the difficulties associated with the abrasive blades, particularly: excessive heat build-up, and a lot of mess. But, considering it was a much cheaper blade (~$6 rather than ~$70), I was hoping it would be good enough. I did keep the receipt so's to be able to return one or both of them.

Before getting started, I verified that the RPM on my miter saw was less than the rated RPM on both purchased blades.

Note the "4900 RPM" rating in the lower-right corner.

I cleaned up sawdust in the area. Then, using some spare sheet metal I had lying around, I built a small shield to install behind the blade and arrest (or at least slow down) the bulk of the sparks. It fit nicely at the back of the table on the saw.

NOTE / spoiler alert: I didn't actually start taking photos until after I'd changed blades.

When I got around to using the carbide-tipped blade, I installed it with the labels facing to the right, which I would normally consider backwards. As you can see, though, this ensured that it turned in the correct direction.

I got the abrasive blade installed (might as well start with the cheap one!), though -- to my later chagrin -- did not measure it before I began using it. After a couple cuts, I had to concur with what I'd read online: lots of heat and lots of sparks. I had my mini IR thermometer handy and measured up to 170˚F in today's heaviest workpiece (1/4" steel, 1.5" wide). The sheet metal guard I'd made got up to 130˚F. Even in the test pieces I cut (1/16" rod and 1/16" tube), I don't think anything was less than 120˚F after the finished cut.

In hope of reining in the fire hazard, I bit the bullet and opened up the package for the carbide-toothed steel blade and installed it.

Oh, what a difference! Instead of grinding its way through a hunk of metal, flinging a fine pyroclastic powder all over the place, the saw now made its way easily through each piece of metal I asked it to cut. There were certainly still sparks, but way fewer of them and not for nearly the duration. Cuts were quick and easy, with nearly no heat build up on the blade, in the workpiece, or on the deck. Workpieces started at ~65˚F and never got above the mid-80s. Additionally, cuts were clean, with none of the slop that the abrasive wheel left behind.

Abrasive cut-off wheel	Steel blade

1/4" Steel (1.5" wide) Left: cut with steel blade; Right: cut with abrasive cut-off wheel

So, overall, I'm pleased. After the test cuts, I made 16 cuts through 1/4" x 1.5" steel. This will make practice pieces for some welding. As I was cleaning up the cuts that the abrasive wheel had made, I noticed discoloration due to overheating left behind by the abrasive wheel. Glad to have the steel blade.

Note: I did end up touching up all of these small pieces on the grinder, but the only ones that had dangling shreds of metal were those cut using the abrasive cut-off wheel.

Also, I definitely had on the wrong gloves for this task. They didn't have any holes in them when I started...

Introduction

Kind of skipped the introduction and went right into ranting, didn't I? Well, let's see about correcting the oversight. This blog is really just intended to be a continuation of the Xanga blog I started years ago (http://nepsis.xanga.com/). I would've posted the previous entry there except that it was inaccessible for some reason (perhaps some firewall on the work computer or their system), and I really wanted to post it. So, I started yet another blog here on Blogger. You may notice that I've got a couple other blogs here with more specific purposes. I don't keep up with them all too well, but perhaps I shall one day.

So, really, this is just a personal general blog, which I expect to cover quite a wide range of topics. I've never been especially good at keeping up with my journal or blog(s), so it won't be updated all too frequently. Here it is, though. Enjoy.

Metta.

A public health rant

20101214, 07:51
Had a really interesting discussion at lunchregarding personal responsibility and its interplay with public health regulation. Kind of started by talking about raw milk. Much of this has come out of conversation with She of the Wee Abode and readings inspired by her. It sounds like there’s quite a little bit of outcry these days from folks who want to have the ability to choose the things that they think will make them healthy. Seems like an obvious enough right, but the way our regulations are currently designed doesn’t really lend itself toward a personal responsibility standpoint. So many lawsuits and public outcries in the past have created a litigious society looking to place blame, which has consistently gone toward producers. This, I think, has led to our current situation where the government is essentially responsible for the health of the public. As such, it dictates things that are unhealthy and not appropriate for human consumption. When it comes down to it, though, our science is not all-knowing, not even as close to all-knowing as we like to think it is. This is evidenced in the constant flux of fad diets and emphasis on what’s healthy and what’s the current pathogen craze, etc. I think it all comes back to the bond between responsibility and freedom. Folks seem to want the freedom to drink raw milk and eat sustainable and local food items produced under alternative schemes, but we’ve had years of folks (not that they’re necessarily the same folks) failing to take responsibility for the outcome. Oddly enough, a similar topic came up later in the day, involving a comment about signing waivers. Perhaps that’s what it’s come down to: every time someone purchases what’s considered to be a “risky” product, they have to sign a waiver to demonstrate that they’re taking responsibility for the outcome. Prior to signing the waiver, they may request to tour the facility (dairy, slaughter facility, whatever), but when they sign that waiver they’re essentially accepting the potential dangers with the product.

The role of regulatory public health is what’s essentially in question. There’s no doubt that it has had a beneficial impact on the health of humans: vaccinations do prevent disease (i.e.: smallpox and polio), sanitation does drastically cut down on epidemics (cholera in Snow’s day, and even in Haiti now). People live better and longer lives when there’s someone looking out for public health. And there are certain things that really do need to be mandated to accomplish these feats. Where does that cross into interference with personal freedom, though; and also, where does that enter the realm of the impossible. One of the things that I heard at the conference in MN a few weeks ago that needs to be stated louder and more often is the fact that we’re all going to die. No matter what, there will be some disease or deterioration that will end each and every one of us. We get too caught up in living forever (if we ever figure out how to do that, we’ll have an even bigger problem) when we should be focusing on living well – too focused on quantity when we should be focused on quality. Then public health regulations get caught up in the chase for quantity rather than quality. I’m reminded of juggling for little kids: “three balls? So what? Can you do 5? What about 8? How about 20? Oh, you can’t do 50? pffft.”
08:24