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Ed Fasano

Ed
Senior User
Miter saw help, please. I’m stumped. My Delta 36-225 10” compound (non-sliding) miter saw, equipped with sharp Freud LU85 is producing 90-dgree cuts that are crowned. What I’m calling a crown amounts to a cut that curves ever-so slightly outwards from the edge closest to the fence, reversing its direction near the center of the width of a 5-inch crosscut, i.e., convex. The cut at the edge closest to me (away from the fence) appears to be perpendicular with the cut on the fence edge. However the cut, with its protruding crown is far from straight / flat. Additional conditions include:

I have tuned all available adjustments to the very best of my ability, using reliable, accurate squares and a dial indicator. The blade is square (vertically) to the table. The fences are aligned with each other and together are square to blade plate.
I cleaned the blade of all pitch. Cuts are acceptably square to their faces. A dial indicator on the blade plate suggests an out-of-flat condition of approximately 0.002”. The arbor configuration, combined with my skill and tools did not allow me to measure the arbor for run out.

A Delta tech rep diagnosed the problem as blade heeling, but could not offer a means of correcting it, so I didn’t put full faith in his opinion.

The outer blade thrust washer appears to have lost its grip at some point, leaving a circular scratch pattern on it and on the blade plate. I do not recall a particular violent situation that would have jerked the blade free from the washer’s grip. Unfortunately, I cannot pinpoint when that slippage occurred and with that, I cannot conclusively tie it and/or the now marred washer and blade to this problem.

That’s the best explanation I can offer. Any thoughts and/or advice will be greatly appreciated. Is there a special adjustment of some sort? Do I need a new blade, a new thrust washer, a new saw? Do I need to abandon woodworking?


Covex_Crosscut_Diagram.jpg
 
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Ed Fasano

Ed
Senior User
blazeman45,

I meant to include that. Yes. I mounted a Freud 60-tooth triple chip. It introduced a new issue, in the form of disturbing vibration. I'll look into that problem later. The shape of its (one) cut seemed to have a similar curve. I wasn't comfortable running it after that test cut.

Thanks.
 

jhreed

New User
james
I am guessing, but maybe the issue is around your arbor washers. Your bevel setting is at a true 90 degree but the arbor is holding the blade cocked 1/64" at the rim but true at the arbor. The second blade is vibrating because the arbor washers are not flat against the plate.

Hopefully, some one who knows will chime in on this issue. Mine is a guess.

James
 

Skymaster

New User
Jack
along with JH's thoughts, pull the blade and washer off, clean really good at the joint of the arbor and the fixed "washer" portion,small wire brush whatever works, be especially critical of the 90% joint. It may have hard buildup that is not allowing the blade to fully slide up against it.
The symptoms seem to suggest either loose blade or bad blade. Since you tried a new blade and it vibrated badly sure sounds like the blade was loose. Also before you put the thrust washer back on, put a pc of fine emery cloth or sandpaper even, face up on a real flat surface, like cast iron TS top :}, and flatten the washer surface until you can see contact with every portion of it.
Other than that I have no other ideas :wsmile:
 

CDPeters

Master of None
Chris
Sounds like the blade is shifting right to left as it swings down through the cut. If you have a dial indicator, see if you can measure the body of the blade as it travels downward for this shift.

I'm thinking the arm pivot and the blade arbor are not quite coaxial. Does the crown of the cut (center of the board) show any sign of burning which might indicate that part of the stock is rubbing on the body of the blade once the teeth are through the cut at the center?

You might also check the arbor for side to side lash and be sure the arbor flange has no run out.

My $0.02 FWIW...

C.
 

Ed Fasano

Ed
Senior User
First, thanks to all who are contributing thoughts about my miter saw dilemma. Being new to NC and new to the group, I’m thrilled with the responses—regardless of the outcome.

I trued up the arbor thrust washers to the best of my ability and I found the 40-tooth, 0-hook carbide blade that came with the saw. I mounted that virgin (albeit mediocre) blade. The shape of the cut was unchanged, i.e., the edge is still crowned. The face of the cut is clean with respect to burning.

I’ll jig up a dial indicator and next try to determine if there is a variance coaxial relationship between the arm pivot and the blade arbor. However, as there are no adjustments for this type of alignment, shimming the plate where the arm attaches to the base appears (to me) to be the only way to “correct” this type of problem.

Failing that, I get to research a new miter saw.

Again, thanks to all!
 

Skymaster

New User
Jack
UHHHHHHHHHHHHHHHHHHHHHHHHH wait a minute :wsmile: Ed; Say again ZERO hook blade? that wood be the WRONG blade for a miter box, a Zero hook is normally used on a radial arm. I suggest you get a blade for a miterbox and try it before you drive yourself up a wall looking for a problem that might KNOT exist :gar-Bi Lets start simple and get the correct blade and then see what gives;
:gar-Bi:gar-Bi
 

Ed Fasano

Ed
Senior User
Skymaster,

I double-checked the low-grade Delta blade I used as a process of elimination. It's clearly marked "0-degree hook angle" and "For Radial Arm Saws and Miter Boxes." That doesn’t make it right, it's just what's printed on the blade that came with the saw. However, as I'm increasingly confident that my issue is most likely with the saw, not the blade, I'll be putting the 10-degree Freud LU85 back on. I’ll study up on hook angles and applications though. Thanks.
 

Skymaster

New User
Jack
Darn Drat :} if n u wuz closer I wood head over and see this rascal eyeball to eyeball. My instincts tell me it is a very simple problem but it eludes me cause I cant see the bugger. I am a trimmer for 30 yrs and miterbox is my main tool.
I trust you have cleaned EVERY moving part or joint. remember not only do u have l to r table the head also rotates, you could be perfectly square tablewise but the head could be out of plane. Quite a few little bugs to create a real mess. It still sounds like blade to me. If you square the cut, both the starting corner and outside corner are square and the center pushes out right?
do this; make a cut, find some way to prevent the board from moving; draw square line, make a cut as close to that line as u can BUT still leave the line, eyeball it, you will see exactly how the cut went, lets presume it bellies out in center; NOW cut it again,NOTHING MOVED,EXACTLY IN PLACE OF FIRST CUT. IF the second cut goes dead on the line then NOT machine it is the blade:gar-Bi:wsmile:
if ya need 1 1/2 brains to talk to 919-375-4442 i am home :{ 99% of time
Jack
 

CDPeters

Master of None
Chris
Jack -

The more I think about this the more I think you're right. Wouldn't blade cup cause this in a miter saw? Not in a table saw - the blade/workpiece attack geometry is totally different.

Maybe the arbor flange is not flat or has some buildup of some sort causing the blade to cup when tightened down? 0.016 over a 5" cut is ALOT!

Would there be any benefit to testing with a blade washer between the blade and the arbor flange just to see if anything changes?

Just thinking out loud....

C.
 

Skymaster

New User
Jack
CD; Yes you r right. That is why I suggested he really really examine the flange washer joint at the arbor. I have had issues where there was enuf buildup to **** the blade just a few thou BUT that little bit was enuf to negate the clearance on the tooth grind. without clearance the blade rubbed and pushed off. a double cut would clean it up cause first cut in full material actually causes problem, second no pressure on blade allows it to cut square
 

Asheville Hardware

New User
Asheville Hardware
Ed, can you get some close up pictures of the arbor and flange and maybe the arbor hole on the blade? Not sure it would help, but something might be visible there.

I'd tend to agree with Jack's diagnoses by the way.

Scott
 

Ed Fasano

Ed
Senior User
Jack – I really appreciate the good fortune of having all this experience as part of this process and I wish I was closer too. Oh well. I have a reasonable appreciation for the potential for a number of variables to affect each other. Everything is clean and as tight as the tool’s design will allow.

Yes - the starting corner and outside corner appear square. It’s the center that is proud of the two corners. I could be exaggerating the bellied point as 1/64th, but whatever it is; I can rock a trusted Starrett straight edge back and forth across the cut. And, with the straight edge held at an angle that equalizes the error at both corners, I can see light at both corners. While I’m not the sharpest chisel on the rack, even I know that this means the cut isn’t straight (flat).

I wonder too if I should try replacing the two thrust washers. I need to check into the whereabouts of a Delta parts center in the Triad.

I’m eager to try the test cut(s) you prescribed and to put a dial indicator on the blade’s face (as it travels on its vertical pivot). I can’t get into the shop until later today. I’ll let you know what comes of it.

Thanks!!

Ed
 

blazeman45

New User
Steve
Ed,

If I am not mistaken there is a Dewalt / Delta service center on W Wendover Av in Greensboro near Merritt Dr. Good luck with it.

Steve
 

gator

George
Corporate Member
Ed,

If I am not mistaken there is a Dewalt / Delta service center on W Wendover Av in Greensboro near Merritt Dr. Good luck with it.

Steve

Thats right, I just passed it on Sunday. Between I-40 and Holden Road. At least there was a sign on the front of the building.

George
 

Ed Fasano

Ed
Senior User
Update: Miter saw conundrum (more than you ever wanted to know)

I took some pictures of relevant miter saw components (as requested) but have not yet worked the files for uploading. I held off because I discovered a new issue that, if corrected, might lead to a resolution. On the other hand, this problem just might prove to be the straw that forces me to replace this saw.
The newly-discovered issue is the fact that the left side of the rotating segment of the table is about 0.012” higher than the adjacent (fixed) base. The height variation of the right side is about 0.004”. In other words, the rotating table isn’t sitting flat (side-to-side), nor is it level with the base.

In addition to this discovery, I did my best to measure change in the blade face (left side) as the saw is brought down through its cutting arc. The best measurement I can get wouldn’t satisfy an engineer or a machinist, but curiously, the deviation though the portion of the arc that I can measure (the travel during which I could keep a dial indicator on the blade face) is all-but identical to the left side table height variant.

So, I dismantled the base and rotating table to find that the slick glide button heads that keep the table from rotating against the metal of the base protrude unevenly and the unevenness seems to closely resemble the table height error. I shaved these glides to the best of my ability, which left the table much closer to level (left-to-right) and more even with the adjacent base surface. However, without a fine means of shaving glide buttons, the table no longer sits quite as evenly on all of the glides – i.e., I can rock the table slightly. The rocking disappeared when the table was bolted to the base during reassembly.

I’m almost thru with reassembly and complete readjustment, nearing the point at which test cuts will tell the tale. If there’s improvement, I’ll celebrate and give thanks to all who kept me energized about this. If the problem remains or if I’ve made it worse, I’ll consider replacing the arbor thrust washers and the blade (as a last resort) or just seek out a new, rock solid non-sliding miter saw (and blade) on which I can rely.

I’ll update when there’s something to update.
 
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