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Problems getting square cuts w/ circular saw

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Forum topic by optimusprimer92 posted 04-12-2017 02:39 AM 811 views 0 times favorited 10 replies Add to Favorites Watch
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optimusprimer92

21 posts in 402 days


04-12-2017 02:39 AM

Hey guys. I am having a heck of a time getting square edges with my circ saw. Today, I bought a new Makita Magnesium saw. Supposed to be pretty good. I checked for square and got the blade at 90 to the shoe. I then built a door board (rip fence) for the saw. The saw is the standard blade-right orientation so the saw rides along the fence on the left side of the fence, where the motor is. After making a cut on some ply, I looked at the cut and it was horrible. Probably 4 degrees off. I am absolutely miffed as to how this is happening. I take special care not to torque the saw either way. I did notice however, that the blade is not parallel to the left side of the shoe. The front of the blade is a little less than 1/32nd out of parallel with the back. However, the blade is perfectly parallel with the right side of the shoe, aka the skinny side. When I run the saw along a straight edge from the right side, I get good cuts but not with my cutoff jig. What gives?!


10 replies so far

View papadan's profile

papadan

3584 posts in 3208 days


#1 posted 04-12-2017 03:12 AM

Square to the shoe would not cause it not to cut square on the edge. What kind of fence did you build? does the saw ride on it or against it.

View woodbutcherbynight's profile

woodbutcherbynight

3650 posts in 2249 days


#2 posted 04-12-2017 03:30 AM

How thick was the material?

-- Live to tell the stories, they sound better that way.

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optimusprimer92

21 posts in 402 days


#3 posted 04-12-2017 03:38 AM

The fence was 1/4” MDF that the saw rides on. The blade cutoff is the alignment edge. I was cutting 3/4” plywood. I just went out and tried it again. Same result. Blade is perfectly 90 to the shoe. If you hold the plywood on edge and look at the edge from top to bottom, it looks like a /. No matter what I do, I cannot get a straight cut. I wouldn’t worry about it too much but I just dropped $160 on this new saw and the length of cut is greater than my table saw’s capacity.

ps- I make double sure not to torque the saw to the outside edge in order to try and prevent the blade from angling inward.

View Kelly's profile

Kelly

1821 posts in 2784 days


#4 posted 04-12-2017 04:10 AM

Shame the fence wasn’t an inch or two out into the MDF. Then it could be used to run either the wide or the narrow side.

If the plate isn’t square on the left, it just added that much to the blade thickness (running through the wood sideways). If using a thin kerf, could it be deflecting?

Be interesting to see what a cut off the narrow side did. I use that side for straight cuts frequently.

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optimusprimer92

21 posts in 402 days


#5 posted 04-12-2017 04:37 AM

The blade is a thinner kerf Freud 60 toother. It doesn’t seem to make a difference ignoring I put in a rip blade though. Might just take the saw back. I worked for 4 hours today to try to get it to cut square. Didn’t work. If I run a fence on the motor side, the cuts don’t square up but if I use the thinner side to run my fence along it seems alright. The problem is I need to be able to rely on The other side cutting square so I can trim glued up panels.

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optimusprimer92

21 posts in 402 days


#6 posted 04-12-2017 09:43 PM

So, I am fairly certain I now have an answer and I thought I would post my findings. After messing around w/ the bevel adjustment and measuring the blade distance from outside of shoe ad-nauseum I came to the following conclusions:

1) Since the measurements for the saw were perfect, it must be some error in saw travel or form. No matter what I tried, the result was the same: cut deflects down slightly to the right away from the motor housing.

2) Whether riding on or against a fence positioned to the left of the motor, the cuts would angle in the same manor, HOWEVER, when positioned against a fence to the right side (aka the thin part of the shoe) there was ZERO blade travel. This was only true when the fence was clamped. When I held the fence with my hand, there was opposite blade deflection down to the left.

3) When I free handed the saw w/ no fence, there was no blade deflection. Perfect 90 degree cuts.

4) It appears to me that the torque from the motor wants to pull the saw into the fence when positioned to the left thus causing slight blade angulation once the teeth pass the plane of the work piece. When the fence was positioned to the right and clamped, there was no noticeable torque and ZERO blade deflection. This was interesting in that my form was the same for both scenarios. My guess is that the torque of the motor doesn’t affect the cut when I put the fence on the right side and against the shoe.

This is what I found today. Anyone experience anything like this?

View Steve's profile

Steve

57 posts in 299 days


#7 posted 04-13-2017 03:15 PM

I spent a lot of time over the years with Guides and fences with mixed results. I really fret over how to spend my limited budget and finally bit the bullet and bought a track saw (Dewalt). I wish I had done it years ago, now one of my favorite tools, and I use it for many things other than getting perfect cuts on sheet goods.

I know its a lot more $$$$, but your new circular saw was not cheap and it terms of bang for your buck its certainly something to consider. I only bring this up since you are considering returning the saw.

Best of luck!

View ArtMann's profile

ArtMann

691 posts in 656 days


#8 posted 04-14-2017 02:14 AM

The edge of the “shoe” that touches the saw guide is the one that must be exactly parallel to the blade. The accuracy of the edge closest to the blade is irrelevant. Not all circular saws are made so that a saw guide will work correctly by default. You may have to adjust the relationship between the edge of the plate (“shoe”) that rides against the fence and the blade for yourself. At least one company sells a kit that includes an adjustable auxiliary plate that attaches to the original one.

I used a circular saw and saw guide for a long time and got pretty good results. I finally bought a Makita track saw and it provides cuts that are as good as those from my table saw or miter saw. I wish I had bought one sooner.

View realcowtown_eric's profile

realcowtown_eric

608 posts in 1777 days


#9 posted 04-14-2017 02:52 AM

Take a look and see if the motor body aint’t high enuf to clear yer jig. Been there done that.

My 8 1/4 dewalts have adjustments for the base plate.

Good luck.

Eric

-- Real_cowtown_eric

View hotbyte's profile

hotbyte

989 posts in 2815 days


#10 posted 04-14-2017 11:07 AM

Just a thought…but if the blade isn’t parallel to edge of base you are running against fence, that could cause blade to try and track away from cut but you holding in place could cause blade to deflect and make non-square cut. As mentioned above, work on that non-parallel issue and retest.

Also, can you explain what you mean by “on a fence”? I assume the base is still running against a guide that is also on the fence?

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