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Miter saw not cutting straight back?

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Forum topic by Fuzzybearz posted 05-23-2019 03:14 AM 351 views 0 times favorited 10 replies Add to Favorites Watch
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Fuzzybearz

104 posts in 457 days


05-23-2019 03:14 AM

Hello everyone

I have a Bosch gcm12SD. When I go to making a 90 degree sliding cut, I always feel resistance near the end as I push the blade back. I also get cuts like the picture where it is smooth once it starts the cut at the end, but then has tear out towards the center. Where should I check for squareness? Or what could be causing this


10 replies so far

View Aj2's profile

Aj2

2266 posts in 2186 days


#1 posted 05-23-2019 03:27 AM

Look normal too me. Try to picture the direction the teeth on the blade are turning. The first half of the cutting they are going down the back half the teeth are rising up.
Almost all the wood I cut on my Bosch glide will bind on the end of the cut.
Tension in the wood+ negative rake saw blade.
Good Luck

-- Aj

View Rick  Dennington's profile

Rick Dennington

6535 posts in 3582 days


#2 posted 05-23-2019 05:12 AM

I have a DeWalt 12” SMS, and I use an 80 tooth blade with no tearout. You might try making a light “skim” cut across the entire board, then bring it back to the front, and begin to make your initial cut. It should be clean across the board out to the end. If you’re using the blade that came with the saw, try a blade with at least 60-80 teeth.

-- " At my age, happy hour is a 2 hour nap".....!!

View Fuzzybearz's profile

Fuzzybearz

104 posts in 457 days


#3 posted 05-23-2019 06:30 AM

I’m using a Forrest chopmaster blade. Sooo it’s not the blade hopefully.

I believe I measured my cuts to make sure they were square too, I’ll check again tomorrow. If that’s square I can check to make sure it’s not a beveled cut?

View HokieKen's profile

HokieKen

9496 posts in 1526 days


#4 posted 05-23-2019 05:19 PM

When you extend the blade to start the cut, the teeth are exiting the top of the board at the back. There is no support there to prevent some tearout like you’re seeing. Take a skim cut starting at the back of the board and pulling the blade out. Then make your thru cut like normal. The skim cut should prevent the tearout.

-- Kenny, SW VA, Go Hokies!!!

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MrRon

5483 posts in 3631 days


#5 posted 05-23-2019 07:12 PM

The tearout on the left side of the board would indicate to me that the blade is set more to the left than the right. There is virtually no tearout on the right side.

View Andybb's profile

Andybb

1920 posts in 991 days


#6 posted 05-23-2019 09:05 PM

Not really sure what you mean by “straight back”.


When you extend the blade to start the cut, the teeth are exiting the top of the board at the back. There is no support there to prevent some tearout like you re seeing. Take a skim cut starting at the back of the board and pulling the blade out. Then make your thru cut like normal. The skim cut should prevent the tearout.

- HokieKen


+1


The tearout on the left side of the board would indicate to me that the blade is set more to the left than the right. There is virtually no tearout on the right side.

- MrRon

Good eye! How would you correct for that?

-- Andy - Seattle USA

View Aj2's profile

Aj2

2266 posts in 2186 days


#7 posted 05-23-2019 10:24 PM

To correct the tear out on the left you need to lean to the right when driving that saw. Aka the gangsta lean. :)

-- Aj

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Andybb

1920 posts in 991 days


#8 posted 05-23-2019 10:51 PM

I think I’d follow Ken’s advice and call it a day. I use my MS (Bosch) more for sizing than final finish cuts.

-- Andy - Seattle USA

View therealSteveN's profile

therealSteveN

2812 posts in 962 days


#9 posted 05-24-2019 04:24 AM


Not really sure what you mean by “straight back”.

When you extend the blade to start the cut, the teeth are exiting the top of the board at the back. There is no support there to prevent some tearout like you re seeing. Take a skim cut starting at the back of the board and pulling the blade out. Then make your thru cut like normal. The skim cut should prevent the tearout.

- HokieKen

+1

The tearout on the left side of the board would indicate to me that the blade is set more to the left than the right. There is virtually no tearout on the right side.

- MrRon

Good eye! How would you correct for that?

- Andybb

Check your saws 90* setting with a known good machinist square. I imagine you have about a degree or so of lean that is tickling the left side, so guessing on outcome 1 to 2 degrees leaning left now. If it’s dead on, you either have a whacky blade, or saw. But you might try that lean dance, worst could happen is passers by would LTAO. Check it on the blade tilt, and then on the bed angle just to make sure it’s 90 and 90, when it says it is. Both should have an adjustable indicator.

Never trust that the indicator indicates anything close to the truth, unless you have set it to dead 90 yourself. If you did, and it moved, tighten harder. Actually that is when you bring out the locktite. Just on the set screw on the indicator will only keep the indicator correct.

Kens advice to score cut is dead nutz on.

“I think I’d follow Ken’s advice and call it a day. I use my MS (Bosch) more for sizing than final finish cuts.”

Always smart. way too much wiggle at the top end of them to consider them for accuracy, and definitely not repeatability. Even with stop blocks you will/can see differences. Hold the saws bed still with your left hand, and with the arm up, wiggle it back and forth a bit with your right hand. 1/4 to 1/2” isn’t rare. If TS’s were that sloppy we would all be using hand tools. Rough cuts only is a good idea. Basically a tool made for the framing of houses.

-- Think safe, be safe

View Fuzzybearz's profile

Fuzzybearz

104 posts in 457 days


#10 posted 05-24-2019 04:31 PM

I was just a bit worried as it would sometimes bind up. At the end. But that may be due more to the wood warpage as I deal a lot with rough cut 2×12 cedar that is often green. Don’t need too much precision for what I do so I’ll leave it as is. I’ve checked for squareness with my woodpecker square. And it seems good.

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