Router speed control on circular saw?

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Forum topic by Viktor posted 05-10-2011 07:04 PM 4902 views 0 times favorited 13 replies Add to Favorites Watch
View Viktor's profile


455 posts in 2508 days

05-10-2011 07:04 PM

Topic tags/keywords: question router tablesaw

1) Would a speed controller used for routers work on a circular saw? I imagine it would as both use same type of motors. I need to cut plexiglass (acrylic) and the cutting speed on the saw is just too high. It cuts, but not very good. Plastic smells and nearly melts. I doubt using specialty blade will help. I thought if I could reduce the speed it might cut much cleaner.
2) Related question. Does using speed controller (either with router or saw) has any adverse effect on the motor, short or long term? How does it effect performance (torque etc.)? I would be interested in your practical experience as well as theory.

13 replies so far

View Loren's profile


7967 posts in 2737 days

#1 posted 05-10-2011 08:21 PM

1. it should work ok. Some specialized or higher-end saws have a
speed control built in, just like routers.

2. running a router in a table at lower speeds will shorten its life. That’s
because (a) dust falls down in the motor, regardless of speed, when
you invert the router, and (b) the fan in a router goes with the speed
and it’s designed to cool the unit at full speed.

Routers these days are getting so affordable I wouldn’t worry about it
too much, but don’t use your best routers at low speeds in a table.


View Viktor's profile


455 posts in 2508 days

#2 posted 05-10-2011 10:34 PM

Thank you, Loren. That was very helpful. Good point about fan speed, did not think about that. Meanwhile I searched around about torque reduction. It seems that if the controller has electronic feedback feature to maintain constant motor speed (and not all of them have it), then torque will also be maintained. Perhaps electricians here could correct me.

View Howie's profile


2656 posts in 2012 days

#3 posted 05-10-2011 10:53 PM

Might be cheaper and easier to use a different blade. One made especially for cutting plastic.

-- Life is good.

View SCOTSMAN's profile


5784 posts in 2674 days

#4 posted 05-10-2011 11:11 PM

I cut plastic with a good high tooth blade and it cuts fine don’t fart about with blade speeds, it’s dangerous in my sincere opinion saws are designed to run fast not slow. Alistair

-- excuse my typing as I have a form of parkinsons disease

View FirehouseWoodworking's profile


663 posts in 2362 days

#5 posted 05-11-2011 02:10 AM

I agree with Alister. Don’t mess with the speed. The high tooth number blade is the way to go.

Make sure you clamp the plexiglass down and support it on both sides of the cut. If you are still having a proble with chip out or whatever, try running a scoring cut on each side to just cut through the two surfaces, then making the cut-through pass.

The best option, though, if you can do it is to use a high tooth blade in a table saw.

Good luck! Cheers!

-- Dave; Lansing, Kansas

View Grandpa's profile


3246 posts in 1765 days

#6 posted 05-11-2011 05:40 AM

I have cut some plastics using plywood blades which goes along with these guy. The more teeth the better. Carbon steel plywood blades.

View devann's profile


1920 posts in 1782 days

#7 posted 05-11-2011 06:19 AM

I agree with the above, more teeth on the blade. If you want to use a slower rpm circular saw, use a worm drive. ( skil model 77 ) They turn at 4400 rpm as opposed to the 5800 rpm of the other circular saws. If the plexiglass is not very thick you could probably use a scoring tool like is used to cut plastic laminate. Cut both sides.

-- Darrell, making more sawdust than I know what to do with

View Occie gilliam's profile

Occie gilliam

505 posts in 2385 days

#8 posted 05-12-2011 03:20 PM

Hi Viktor
this could help

-- OC down in Costa Rica. come down and see me some time. I'll keep the light on for you

View Jamie Speirs's profile

Jamie Speirs

4166 posts in 1946 days

#9 posted 05-13-2011 01:05 PM

I use the bandsae

No problem


-- Who is the happiest of men? He who values the merits of others, and in their pleasure takes joy, even as though 'twere his own. --Johann Wolfgang von Goethe

View ksSlim's profile


1141 posts in 1979 days

#10 posted 05-13-2011 01:19 PM

High tooth blade and smear the cut line with petroleum jelly to abate melting.

-- Sawdust and shavings are therapeutic

View Loren's profile


7967 posts in 2737 days

#11 posted 05-13-2011 06:43 PM

When you use a smaller diameter blade than the saw is meant
for, your reduce the rim speed too. This can be a good thing.

Circular saws were around before electric motors and can run and
cut pretty slow.

I’ve been in a few plastics shops and they use standard table
saws and panel saws to cut the stuff. There are special blades
rated for it.

I think you can fix the edge of a plastic panel after cutting by
hitting it with heat. The rough parts melt and the edge softens.

I’ve worked with plastics here and there. I mostly fix the rough
edges with files and sandpaper.


View bubinga's profile


861 posts in 1757 days

#12 posted 05-13-2011 08:12 PM

Best blade for plastics, is a Triple Chip Grind ,it will also cut aluminum
Using a specialty blade will help, immensely

-- E J ------- Always Keep a Firm Grip on Your Tool

View veneerguy's profile


17 posts in 1662 days

#13 posted 05-13-2011 08:51 PM

technically you want to increase the speed not reduce it when cutting plexi. what kind of saw are you using, table or circular? you really shouldn’t increase the speed on either saw and should use a table saw to rip or cross cut and a router. tri-chip blade is really the only blade you should use for plexi.

the speed on a table saw blade is faster than that of a circular saw. and a router of course faster than a table saw

to deal with the edges and remove saw marks you should sand with a block to a reasonable smoothness 180 grit, then peel the protective paper back and torch the edges with a propane torch. this will give the edges a glass smooth look. just pass the torch over the edge a couple of times . dont “camp out” with the torch.

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