Strange Issue with SCMS

[patlaw]

Today I had a strange thing happen on my sliding compound miter saw. It was set up on a table on my back deck. It had been out there for a few hours. All of the boards I cut earlier today were fine. However, just before I brought the saw in, I cut a 10" shelving board. The Freud Diablo blade had trouble going through the 3/4" board. (The wood had been inside the house for days.) The blade burned the wood. Thinking the problem was sawdust on the table causing the board to flex and pinch the blade, I cleaned the deck and did another cut. The same thing happened. What's going on here? The saw acted like the blade was dull, but not only is it new, but it worked perfectly all day.

 

[CrealBilly]

Is the blade on backwards? It happens...

 

[patlaw]

Is the blade on backwards? It happens...

No

 

[frankc4113]

Is it possible that something moved and the saw fell out of square?

 

[patlaw]

Is it possible that something moved and the saw fell out of square?

No. It sat in the same spot the whole day. Somehow I think the problem has to be temperature related, which makes NO sense to me at all.

When a blade burns like that, shouldn't it be cleaned? If so, what do I clean it with?

 

[Mike Davis]

Could be that particular board has internal stresses causing it to close up on the blade as it is being cut.
try a different board or a cut off from one of the boards cut earlier in the day.

 

[CrealBilly]

Did the electrical polarity reverse there by causing the motor to spin backwards

 

[SubGuy]

Check your fence square again. I have had mine slip on me and do that. Other things to check, which you may have ruled out already:
1) Board edge against fence straight?
2) Blade tightly secured to arbor?
3) You can check for bearing run out with a dial indicator.

What was the difference in material you cut from one day to the other? (Just thinking if you weren't using your sliding capability before, maybe slides out of whack.

I have had numerous issues with my sliding miter before, most were my fault or wood defects. I hope this helps.

 

[patlaw]

The boards were securely against the fence. They were locked down on the feed side. The outfeed side as not clamped.
The blade is securely tightened against the arbor. I'll double check.
What is bearing run out, and how do I check it? The saw is almost brand new as is the blade.

The same material was cut all day - pine. I used the slide on the burning cut but not the others. I've used the slide with no problem. Nevertheless, I will check it for tracking accuracy.

I hope it's something strange about the wood (which I already cut on the a couple of months ago with no issue.)

 

[CrealBilly]

The boards were securely against the fence. They were locked down on the feed side. The outfeed side as not clamped.
The blade is securely tightened against the arbor. I'll double check.
What is bearing run out, and how do I check it? The saw is almost brand new as is the blade.

The same material was cut all day - pine. I used the slide on the burning cut but not the others. I've used the slide with no problem. Nevertheless, I will check it for tracking accuracy.

I hope it's something strange about the wood (which I already cut on the a couple of months ago with no issue.)

Seriously... Ive cut some wicked wood on mine and the only time i had a issue like that was when the arbor nut came loose which was my fault... for being in a hurry...

 

[SubGuy]

Sometime you need to clean it. What kind of blade do you have? Look for a white to tannish build up around the teeth. If heavy then yes. You can inspect your carbide as well, look for chips and missing teeth. For cleaning I use a dedicated blade cleaner out of a bottle. I specifically use Boesheild Bit and Blade. But most work well enough to clean it out. I have heard of others using some normal home cleaning products or a mixture but I have no experience in using them so I cannot recommend a method outside of cleaners for the purpose of cleaning the blade. Good luck keep us posted and we will narrow it down. Also, Mike is very right. This has occurred to me before as well.

No. It sat in the same spot the whole day. Somehow I think the problem has to be temperature related, which makes NO sense to me at all.

When a blade burns like that, shouldn't it be cleaned? If so, what do I clean it with?

 

[frankc4113]

Soak it in Simple Green or one of those Orange type cleaners fo 10-15 minutes and then use an old toothbrush to clean the residual gunk off the teeth, etc. Dry it real well, possibly using a hair dryer on it to be sure.

 

[patlaw]

Billy, I haven't checked it to see if it's running backwards, but I will. How could that happen? Motor failure? I have not changed anything on the saw.

 

[CrealBilly]

Billy, I haven't checked it to see if it's running backwards, but I will. How could that happen? Motor failure? I have not changed anything on the saw.

Stranger things have happened my friend. But check the arbor nut is tight.

 

[SubGuy]

I believe he was trying to be funny.

Billy, I haven't checked it to see if it's running backwards, but I will. How could that happen? Motor failure? I have not changed anything on the saw.

 

[SubGuy]

What is the brand of saw?
Have you checked you fence against a known metal straight edge? (like a precision framing square)
Don't worry about bearing run out yet, I think it would be a low probability at this point.
Back to our sliding operation. So slider have flex in them when you cut. If you push hard, you can flex the slider arm causing burning in the wood but generally it is occurring on only one side. What side is your burns on or is it both?

The boards were securely against the fence. They were locked down on the feed side. The outfeed side as not clamped.
The blade is securely tightened against the arbor. I'll double check.
What is bearing run out, and how do I check it? The saw is almost brand new as is the blade.

The same material was cut all day - pine. I used the slide on the burning cut but not the others. I've used the slide with no problem. Nevertheless, I will check it for tracking accuracy.

I hope it's something strange about the wood (which I already cut on the a couple of months ago with no issue.)

 

[patlaw]

What is the brand of saw?
Have you checked you fence against a known metal straight edge? (like a precision framing square)
Don't worry about bearing run out yet, I think it would be a low probability at this point.
Back to our sliding operation. So slider have flex in them when you cut. If you push hard, you can flex the slider arm causing burning in the wood but generally it is occurring on only one side. What side is your burns on or is it both?

Yes, the fence is straight, or at least it as a close as I can get it. If it's wrong, the problem only showed up on this one board.
The slider is not flexing, or if it is, I can't see it.
I've already separated the boards, but as I recall, they burned on both sides.

I just checked, and the arbor screw is tight. There does not appear to be any accumulated residue on the blade or teeth.

Argh!

 

[nn4jw]

You say the saw was sitting outside in the cold for quite a while this afternoon. Possibly something slipped or even cracked in the mechanism such that the blade is slightly out of alignment with the path it need to follow when you slide it. In other words, it sounds like the blade is toed in or out some. That’s just a wild guess though.

 

[nn4jw]

I should have added, that’s something that can be checked with a dial indicator fairly easily.

 

[SubGuy]

What blade do you have on it?
Type of saw?


Only three things I can think of if it burn on both sides and you're 100% confident on your fence (by the way they will move or slip sometimes, especially with a hold down pulling upwards on the fence if that is where your's is attached.

1) Outrigger supports high. Causes the blade to pinch.
2) Extreme wood binding.
3) Dull crappy blade.

But as a further point concerning the slide torquing. You will not see it unless you toy with it a bit. I discovered mine by cutting hard maple then pulling the slide back out and checking on the deflection against the piece I just cut by simulating the cut and trying slightly different strokes with the saw. I have tried this "experiment" on a lot of models (excluding the new bosch and a festool, never touched those) and found it in every slider model.