Craftsman CMS

[Locutus]

I have a Craftsman 10" CMS, and it doesn't cut accurately. When it is off and I lower the blade, it appears to be square to the fence. I checked it at

45 deg with a speed square and the blade was at 45 deg. However when I actually cut something, the cut is a few degrees off. The throat plate slot also now looks like a V.

It has done this ever since I owned it, but when I first started using it I primarily used it for rough cutting so I didn't really care. Now that I am getting more involved in woodworking, it's an obvious issue.

Any advice on where to start looking for the problem?

[The3rd Earl Of Derby]

Yep! start looking for a decent one. The Blade is crap on the chinese efforts so a good replacement is in order. You crtainly like the chinese stuff. ;-)

[Locutus]

This a Craftsman, pretty sure it isn't chinese. I think I paid around $300 for it... I have went through several blades, thats does not seem to be the problem.

[Locutus]

Actually I think it was $199, I would think it should work ok for that price.

[Tim Taylor]

I've got one out in the garage I had a problem with. I could get it to cut dead on 90 degrees and it'd be off on the 45. Get it set for 45 and it'd be off on the 90. Get it good on one side 45 and the other would be off. I fiddled with that stupid thing for a month, never did get it right. It's locked in at 90 and sitting on a bench in the garage. It's a good saw other than that. The main reason I don't buy Craftsman any more is the service people in this town suck. They had it for a week and couldn't get it right.

[Dave]

Sounds like the same saw I have, not bad but not great.

I first started with a decent blade by Freud. That solved my not getting a decent cut problem. Then I tackled the actual tuning for square and angular cuts. Ended up taking the whole setup apart and putting it back together checking and rechecking anything that might effect the squareness of the cuts. Spent almost two days on it but it does a pretty decent job. I also built a station for the saw as well so it does not get moved around and is somewhat protected from getting knocked about. My cuts are 100% better as a result. My next saw though will likely be a Dewalt 12" SCMS equivalent or better.

Dave

[The3rd Earl Of Derby]

Lets look at it again,you check for accuracy of 45degrees when the blade is staionary,right so therefore when you cut the 45degrees its out by a few degrees

Does this not tell you something?

It tells me that theres excessive play in the motor shaft.

[George E. Cawthon]

Check the end play of the motor shaft. I have a circular saw that I could never get a straight cut, using a good straight edge. The saw would want to move away from the straight edge. Adding a 0.010" washer eliminated most of the problem. Will need to make and add a 0.003 to 0.005" to get to less than .001 end play.

[support]

I'm afraid that your problem may be the 4th word above "Craftsman". That word used to mean something quite significant a long time ago, but that was then and this is now. It is really quite sad actually. I have seen that name on pure junk. Quite sad.... really....

Steve

[CW]

Sounds like the index plate/detents are of. If it is the type that are cut into the base of the casting, the only cure would be remachining.

[whit3rd]

Well, the V shape slot in the throat plate suggests your blade isn't parallel to the rip fence (i.e. miter gage slots). Some loosening of the table/undercarriage bolts and tapping with a mallet can fix that. The circular saw cuts an oval, not a straight slot, if it's at an angle. Depending on where on the oval the wood rides, you can get a range of cut angles.

Once that alignment is done, there are still issues you might have to look for. The motor -Vbelt tension and a little vibration can shift the set point a little ways, so it might be prudent to adjust/make a test cut/readjust.

There are some good treatments of the general table saw setup, like Power Saws and Planers

[Tim Taylor]

Not meaning to sound stupid, but why would there be a v-belt on a miter saw?

>

[whit3rd]

Oops! I zoned out on the Compound Miter Saw specification... thinking it was a table saw issue. And don't bother with the book, it covers radial and table saws, even bandsaws, but not compound miters.

The basic geometry still holds, though; you need both the alignment of the blade (the angle that was checked) AND the alignment of the plane through which it sweeps when the saw makes a cut (which is harder to check) as well as the various wood-holding pieces.

Another suggestion (worn bearings) seems less likely; the mechanisms I've seen have a large lubricated journal bearing, it'd take a LONG time to wear down. Cracks in the bearing housing could lead to the same effect, though (inspect with a magnifier).

[sweetsawdust]

Mine has a ?toothed? or ?ridged? belt between the motor shaft pulley and the arbor pulley. I think the idea is to save the motor or operator during a sever binding situation. Maybe it is just for speed control. belt cost a $14 when I had to replace it.

[Tim Taylor]

Really? I've never seen a belt on a miter saw. My PC is gear driven. Ok, as I said, it did sound stupid. Now I know! Thanks for the heads up! :-)

[sweetsawdust]

[RayV]

After you check for excessive play as already suggested and ruled it out forget about the speed square.

Set the tilt of the blade to zero and cut the end off of two pieces of wood (2x4 is good size) and then butt the cut ends together on a flat surface like a table saw top. If there is no gap then your saw is truly at zero. Make adjustments until you get this correct. Then tilt the blade to 45 degrees and go through the same procedure to set the

45degree stop.

Then tilt back to zero and turn the table to zero and get a firm seat on the detent and lock it down. Again, cut two pieces of wood and do the butt test to see if you are at zero and adjust the fence as necessary to get this right. Make sure you cut the ends off of both pieces using the same side of the fence. Once this is done you may or may not be able to adjust the 45degree detent, probably not, but everything else should be right.

I also use a similar technique to adjust my TS and it is far more accurate than trying to use a square on a saw blade and either miss the teeth or align only using the teeth.

[Locutus]

[mac davis]

I have the same saw, if it's got the laser crap and the extension for the fence/table...

Mine started doing what you describe at about a year old... turned out to be a pretty simple fix, the nut and lock nut on the saw pivot had loosened, allowing play, which made the blade-to-insert variable...

I tightened it too much on the first try and locked the pivot... trail and errors on adjustment was worth the time as it's been cutting very accurately for a couple of years now.. and yes, it's made in China... check the label.. *g*

Mac

[mac davis]

Good plan... what we forget sometimes is that it's the project that has to fit together, not what the simple or high-tech tools say that the alignment is... YMWV

Mac