Slowing Down Miter Saw to cut metal

[jhendric]

Folks, I have read many threads here regarding ac motor speed controllers and I think the answer to my question is a flat no but figure I'll ask. I have an old non-brushless Makita miter saw that I want to use to cut metal. I need to slow the saw in order to be in the safety zone for the metal cutting blades I want to use. Is it possible for me to use a AC motor speed controller like this one to accomplish this?

AC Motor Speed Controller 120V 15A Variable Speed Controller & Fan Speed Controller, Electronic Voltage Regulator for Electric Motors with Overload Protection, LED Display for Precise Control - Amazon.com

AC Motor Speed Controller 120V 15A Variable Speed Controller & Fan Speed Controller, Electronic Voltage Regulator for Electric Motors with Overload Protection, LED Display for Precise Control - Amazon.com

www.amazon.com

 

[PCustoms]

Product seems legit:

 

[American Locomotive]

How much do you need to slow the saw down? It will slow it down, but you also lose power.

If you need to go from say 4000 RPM to 1000, you likely won't have enough power for it to work

 

[KwikFab]

I'd just buy the appropriate tool

 

[BTL-A4]

I tried this on a bandsaw (Craftsman 10" bench top, if that matters) I had with the Harbor Freight speed controller. It did not work so I took it back. It has something to do with modern motors having some feature that doesn't allow the use of speed controllers. I'll let other chime in on what that is.

 

[seber]

I tried this on a bandsaw (Craftsman 10" bench top, if that matters) I had with the Harbor Freight speed controller. It did not work so I took it back. It has something to do with modern motors having some feature that doesn't allow the use of speed controllers. I'll let other chime in on what that is.

Universal motors like hand drills and skillsaws can be slowed down by simply reducing the voltage. Induction motors get their speed from the frequency, so reducing the voltage just reduces power and increases heat.

 

[tarbellb]

Product seems legit:

OMG I thought you found this randomly and posted as a joke..... Its actually ON the product description page!

bahahhaaa this is to good plus I think dudes silk pajama-overalls will instantly ignite when sparks fly

 

[Codyboy]

I used an abrasive blade on 12" Dewalt and ruined the plastic insert on the table part.
Now I just use a grinder with cutoff wheel or a sawzall.

 

[jmdirk]

Product seems legit:

To be fair, I've used something like that as a speed controller for my motorized bead roller which is using an old garage door opener that I got for free. As expected, it's semi-effective. It works to a degree, but still doesn't go quite slow enough as there's a minimum voltage for the motor itself to provide enough torque to start turning everything. Below a certain point it (the motor) just hums.

 

[jmdirk]

I'd just buy the appropriate tool

Agree. You can get an Evolution miter saw for fairly cheap nowadays

 

[KwikFab]

Agree. You can get an Evolution miter saw for fairly cheap nowadays

Yep!

I gave mine away after using it for just two small jobs.

 

[oldmachinenut]

OMG I thought you found this randomly and posted as a joke..... Its actually ON the product description page!

bahahhaaa this is to good plus I think dudes silk pajama-overalls will instantly ignite when sparks fly

 

[neophyte]

Product seems legit:

Hand drills draw way less amperage/wattage than a miter saw motor does.
Since these motor speed reducers are routinely made to use with routers, some of which max out the power draw on a 15 amp socket,
it might work on a miter saw, which also may be made to max out the draw on a 15 amp socket, it might work, buy you would want to check the specs to verify if a max amperage or wattage is listed.
Also, motor fans are needed to cool motors, and the fans are usually designed to cool the motors at the listed motor speed.
Reducing the speed may reduce the cooling efficiency, which may be fine for a small number of cuts, but bad for extensive use.
Lastly, the motor speed reducer will likely lower the motor power level.
Also, miter saws for metal tend to have way better and stronger systems for keeping the metal being cut fixed in place.
If the metal shifts, it can screw up the blade, particularly over multiple cuts, leading to lower blade life, and also cause **** cuts and potential safety issues.

 

[PCustoms]

For the record my post was sarcasm. I'd never use one of these in a saw for the reasons mentioned, and I'd never use a cheap offshore one.

I have one somewhere, I bought it used 20+ years ago. All my new routers have integrated speed control so it doesn't get used.

 

[tarbellb]

Look for a bench top band saw (Klutch or Femi)
cheap and much better then spraying sparks or dodging hot chips

 

[milky2k]

You can cut aluminum with your miter saw. At least angle aluminum from my experience. I take it you want to cut mild steel. The short answer to your question is no. Here is a video from AvE who is trying to do the same with an abrasive saw but it doesn’t work out.

 

[jmdirk]

Yep!

I gave mine away after using it for just two small jobs.

And...it's one of those tools that you'll spend more on consumables (blades) than you will on the tool itself. I think almost all of those metal cutting blades are triple chip grind too, so they can't even be sharpened easily (or economically)

 

[KwikFab]

And...it's one of those tools that you'll spend more on consumables (blades) than you will on the tool itself. I think almost all of those metal cutting blades are triple chip grind too, so they can't even be sharpened easily (or economically)

Yeah they can be pretty pricey.

I bought it for one job, and it paid for itself.

After which I used it once more before I benched it for about a year.

A customer came out to get something installed on his truck and when he was leaving, he took the saw with him.

It cut pretty well, giving you a perfect square cut, but it was way too loud and blew chips all over the place. I've got a bandsaw I prefer to use but some people swear on those Evos.

Either option is better than the author's intent to use a wood cutting saw for metal.

 

[jhendric]

Hey guys, follow up here. So first off I did this and it worked. Let me address some of the points made.

First off I should have provided more detail in the beginning. I don't pretend that this is a great GJ level solution. I have a 20+ year old makita miter saw that I got for $10 at a garage sale that I really want to find a purpose for. It has a universal motor. I do very little metal work, but I do have a couple of projects where I'll be cutting some angle iron. I bought the very speed controller I posted and a RPM meter. I slowed the saw down to match the specs of the blade I'm using and it worked perfectly for the 4 cuts I needed for this project. I won't hesitate to use it again.

As for the "Village People" outfit in the picture, it hasn't arrived yet.

 

[tarbellb]

Glad you got the project done, I guess that's the whole point

Would be interested in what blade you used

Also give us a update after doing more cuts.... I imagine it may work for lighter cuts or a few but the long term usage and variety of wall thickness may give it trouble?

 

[Nick Rivers]

Also have an old Makita chop saw that used a 10 inch wood blade. I put a 7.25 inch Evolution Rageblade rated for 5000 RPM to cut some perforated angle iron. Works great, but you have to modify the backstop for the smaller blade. Left it as a metal chopper.

 

[jhendric]

Glad you got the project done, I guess that's the whole point

Would be interested in what blade you used

Also give us a update after doing more cuts.... I imagine it may work for lighter cuts or a few but the long term usage and variety of wall thickness may give it trouble?

Blade is a Diablo 14" metal blade. It has a Max RPM of 1800.