# Miter Saw not cutting a straight line



## mini_fly (Dec 23, 2008)

Hi and thanks for the great forum you have here.

I have a brand new 10" Mastercraft Sliding Compound Miter Saw.

I am using it to cut 4" wide mdf trim to make 'frames' to be attached to the wall. Unfortunately, my cuts are not being made true.

When I make the 45 degree cut, I have to pull the saw all the way out towards me to clear the piece before I begin to cut. I'll then drop the saw down and slowly move it back to its home position to make the cut.

The problem I am seeing is that the teeth on the side of the blade closest to me are cutting the trim when I get the saw close to its home position. This essentially causes a bump in the middle of the cut and therefore the pieces do not fit together very squarely.

In other words, the saw is cutting the piece twice when the slide is used.

I have confirmed the angle of the saw to be 45 degrees with a tri square and I have confirmed the saw being plumb to the work table.

When I make a 90 degree cut, I am not seeing the defect.

I changed the 40 tooth blade that was mounted when I took it out of the box to a 60 tooth blade and I am seeing the same defect.

What do you think it could be?

Thanks for your help,

Henry


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## lew (Feb 13, 2008)

Have you checked to see if the rite and left rear fences are aligned with each other? Use a long straight edge (4 foot level or something similar) and place it against the rear fences. Do both fences touch the straight edge along their entire length? If one fence is slightly out of line, it cold cause the material to shift as the cut is completed and the material "gives" and press back against the fences.

This is only a guess and I would think the same thing would happen on a straight cut, too. But. it's worth a try.


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## CharlieM1958 (Nov 7, 2006)

Lew's theory makes sense. It seems to me that misaligned fences* would *be more likely to affect a 45 degree cut than a 90 degree cut.

Another thought: Is the material well supported on both sides of the cut? MDF trim is pretty floppy, and if the offall side is shifting once you are part of the way through the cut, that would create the problem you describe. I would be interested to know if the problem still ocurred when cutting a more rigid type of material, like, say, a 2×4?


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## mini_fly (Dec 23, 2008)

I checked the rear fences and they are both aligned to each other.

I see what you are saying with the material being able to shift if one of the fences did not line up.

I am seeing this defect even when I take a thin cut off of a piece and it is only resting on one of the fences.

Thanks for the quick responses lew and Charlie!


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## Woodchuck1957 (Feb 4, 2008)

Mastercraft, isn't that what Menards is selling ?


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## dustmaker (Dec 17, 2008)

Check the rails to see if there is any play in them when you pull the saw toward you. Hitachi was bad about having play in the rails.


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## mini_fly (Dec 23, 2008)

Mastercraft is a brand from Canadian Tire here in Canada.

The rails seem very smooth without any play that I can determine. It is a new saw but I know that does not say much these days with some of the stuff coming out of the far east.

Here is a link to a 2×4 I just cut. I cut it to 45 degrees first and then just took a little skim off of it to eliminate any possible fence rocking. Both cuts were made slowly.

You can see the defect on the bottom left hand side of the cut.

http://picasaweb.google.ca/lh/photo/OKq1u6V6u4ENFm9cEGXYBw?feat=directlink

Henry


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## SCOTSMAN (Aug 1, 2008)

Perhaps the fence is too far back that's what it looks like to me.And or alos it might be the blade isn't cutting deep enough and not centerring on the wood It might be you need to bring fence forwards or align the slide mechanism so it cuts further back if this is adjustable ask the company .It's only a phone call, but there must be an adjustment.These are facory set normally but it might me you got a friday night job why not ask for a replacement or if this is not possible instructions in how to set it up.Alistair


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## mini_fly (Dec 23, 2008)

The fence looks factory set but there may be some adjustment in it.

The depth of cut cannot be adjusted up or down anymore than it already is.

I'm thinking of returning this one and picking up another saw and trying it.  If I get the same result, I'll go to Sears and get a similar model they have and give it a try.

Just out of curiosity, am I asking too much from a $250.00 saw?

Henry


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## Woodchuck1957 (Feb 4, 2008)

$250 for a slider is not alot of money, and a woodworking saw from a tire company doesn't sound good. But you never know, maybe it's ok. It's pretty tough to diagnose your problem with the saw when a person isn't there to fully look it over, all we can do is guess. It looks to me like the wood is moveing for some reason, is there a cup in the board and it's rocking ?


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## mini_fly (Dec 23, 2008)

I see what you are saying with the possible cupping of the board. Unfortunately, I don't think that the thin trim I am cutting is cupped.

I have used the built in clamp and held the wood with my hand and still seem the same result. I'm sure the wood is not moving.

I may have to agree with you on the fact that I bought a $250.00 saw from a hardware/tire store and I am not happy with my results.

I wonder if my other cost effective option in buying one from Sears is going to get me the same result.

Henry


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## Woodchuck1957 (Feb 4, 2008)

I would stay away from Sears if possible in the mitersaw category. If I was looking for a good mitersaw I would go to Amazon.com look for the best selling and the most favorable reviewed. Not that you have to buy from them, but you'll know whats good and about what the price should be. I have 2 DeWalts, Hitachi's use to be seen at alot of jobsites, I don't know how they rate now.


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## lew (Feb 13, 2008)

See if I understand where this "bump" is occurring. From your picture, judging from the splinters, it is occurring at the edge of the wood as the saw enters the cut- is that correct?

Have you tried to recreate this bump with the power off and just moving the saw along the same track? If the saw isn't running, you may be able to "feel" any change in the saw alignment if there is a defect in the sliding rails.


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## mini_fly (Dec 23, 2008)

Thanks Woodchuk for the advice. I'll do some research as you suggest.

Lew, the 'bump' does not get created till the saw is full parked and is caused by the teeth that are coming around the saw. The side closest to the person operating the saw.

Look in this album. I think I captured it.

http://picasaweb.google.ca/83redmini/Mitersaw?feat=directlink

Henry


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## lew (Feb 13, 2008)

Alright, this may sound dangerous but- try making your cut BUT don't release the trigger. Slide your cut piece away from the blade (with the saw still running) THEN release the trigger. See if the bump is there. Maybe the saw torque, when shutting down, is causing either the blade to shift slightly or then entire motor/head unit to shift.

Lew


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## Karson (May 9, 2006)

It looks like the blade when it starts to cut is shifting to the left. Possible teeth set and then when the blade is no longer fully incased in solid wood it flexes back to the right and the teeth drag and cause the depression.

I would suggest cutting like you are and when the blade get about to the spot that you are finding the problem, pull the saw back to you and then go back and finish the cut. The blade might cut a little more wood off the side that is visible now (I call it the right side) and continue to finish the cut.

You said that it's causing the same problems with two different blades. So I don't know. My theory is suggesting a blade problem,

It also looks like from your series of photos that you are experiencing the problem when you do the cut pulling the saw to you.

Does it happen on every board no matter the width of the board.

Try a board and pull the blade all the way out. Put your board in at the fence and do the cut pushing you blade through the wood. And see if the marks contuinue.

What does the other piece look like

If it happens in the same spot every time is there any bur or something that is causing the saw blade to change directions


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## mini_fly (Dec 23, 2008)

Lew, when I do that, I still see the defect in the board.

BUT, when I use the saw incorrectly, the defect is not there.

By pushing the saw down into the board and pulling it back towards me, I don't get the defect. What it does do is lift up the edge of the trimpiece where it is painted and I get a little sliver that I can easliy cut off with a utillity knife.

Karson, as I said above, I was initially using the saw 'properly' meaning I pull the saw back, start the motor, drop the saw, and push it away from me. When I do it the other way, the defect is not there. I do still see a little bit of a bump made evident when I put a straight edge along the cut and I can rock it a bit.

Maybe I will try to cut my trim pieces by pulling the saw towards me. It seems that the defect is much less that way.

Henry


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## lew (Feb 13, 2008)

I hate to say it, but it almost seems like there must be a "spot" the slides that is causing the entire saw/motor/blade to deflect near the end of the cut (close to the fence position). The reason I think this is that when you push (normal operation) the last part of the cut is left with the bump. But, when you pull (incorrect operation) the saw blade continues past the defect and cleans up the bump as it goes.

Again, I am only guessing. Still not sure if this idea has any validity because you can't see or feel anything in the movement when the motor is not running.


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## mini_fly (Dec 23, 2008)

I'm going to have to leave this problem for a bit since we have to do some Christmas travelling.

Thanks to all for your help so far. I hope you all have a great Christmas or other type of holiday you may celebrate.

Henry


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## knothead (Aug 4, 2007)

Man I can relate to this post - I belive that Mastercraft is sold locally at Menards, personally I bought a Craftsman a few years back and even though I see folks praise their Sears tools here I find that after an interminable amount of tweaking and checking I can only get "Close" with the Craftsman saw and then only if I check it and set it every time I make a cut, Can't wait to save the money for a replacement saw. I find that since I left the world of "good enough" and began the journey towards true craftsmanship and quality, the Sears tools and most other inexpensive tools just don't measure up to any real standards of quality. You can work around the shortcomings of most tools with patience, but I prefer to set it once, adjust it once and move on to the fun stuff.

Hope everyone had a Merry Christmas


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