I need a table saw expert

Don Case

Don Case

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I have a little table saw that I made that I mostly use for cutting planks. It has a 4" 80 tooth blade and turns at 3450 rpm. Up until recently it has worked quite well but now It seems to want to cut tapered planks. If I am cutting ,040" planks it will start out cutting .040" but at the end of an 8" plank it will taper out to almost nothing. I am holding the work against the fence as tight as I can but it wants to move away from the fence I think. I clamp the front of the fence with vice grips so at least the front of the fence isn't moving. I've tried adjusting the fence but I'm not sure which way to go or if that is even the right thing to do. Any Ideas?

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Don Case said:
I have a little table saw that I made that I mostly use for cutting planks. It has a 4" 80 tooth blade and turns at 3450 rpm. Up until recently it has worked quite well but now It seems to want to cut tapered planks. If I am cutting ,040" planks it will start out cutting .040" but at the end of an 8" plank it will taper out to almost nothing. I am holding the work against the fence as tight as I can but it wants to move away from the fence I think. I clamp the front of the fence with vice grips so at least the front of the fence isn't moving. I've tried adjusting the fence but I'm not sure which way to go or if that is even the right thing to do. Any Ideas?

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Obviously something is moving or has moved. The first thing I would do is back the fence away and lay a long (12") straight edge against the blade and carefully measure between the fence and straightedge at the ends to see if everything is parallel.
Also make sure the blade arbor is tight and not shifting slightly during the cut.
At .040 cuts it wouldn't take much of a misalignment to be off.
 
OK I did that and it looks OK. I checked the run out on the blade and it is .010". That seems a little much for a 4" blade. It also makes it hard to check the fence alignment. So I checked the arbor. The blade is actually sitting right where the shaft starts to neck down for the threads. Don't think that's very good. For the first part of it's life this saw had no blade height adjustment. When I modified it so it did have blade adjustment I had to move the blade out on the shaft. I'm thinking know that's when this problem started. I'm going to have to re think this part before I spend anymore time and energy on this problem. Oh, when I reassembled it after all this messing around it cut straight for a few minutes and then went back to no good. Thanks for the advice.
 
My old Dremel table saw does this to me once a while and my problem has been that the fence clamps are loosing their grip. As Paul Ron has mentioned, try a new blade, and check the fence measurements before and after the cut to make sure it stays put.
 
I've already tried two blades. I have one more. The blades are old. They are Thurston slitting blades that I bought years ago. They still cut well. I tried to replace them a few years back and Thurston had quit. I couldn't find any 4" x 1/2" shaft then. I may have better luck now. "But", I'm 77 and kinda think these ones will last me.
 
old blades tend to drift with the wood grain because its plowing instead of cutting the fibers. a new sharp blade will track much better through the grain, especially on rip cuts.

1/2" arbor? lets see what a search will find?

edit... seems 1/2" arbor isnt readily available. see the table here
www.mcmaster.com

McMaster-Carr

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Don,
You might give a call to Donna at Byrnes Model Machines.
As we all know Jim passed away in 2023 and production on new machines is halted however, they are still stocking parts/accessories for the machines. His blades have a 1/2" arbor hole and a variety of teeth and style. His saw is actually a 3/8" arbor and he supplies an adapter for his 1/2" arbor blades.
I don't know what their stock is but might be worth a call. I believe he contracted with Martingale for his blades as most of mine from Byrnes are Martingale.

Sorry Martindale not Martingale. Darn spell checker :(
 
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Hi, Don. Did you change to a harder wood when this happened? My blades wandering left and right when I try cutting something hard as boxwood.
 
Sharpen your Thurston blades! This is actually easy. First clean the blade to get rid of wood resin. There are proprietary blade cleaners but try any solvent that you have on hand. I used some spray on carburetor cleaner.

Next clamp the blade in a smooth jawed vise. Using a triangular small sharpening stone file each tooth. Only a few strokes are necessary but get down into the valley between the teeth. Don’t change the tooth contour. Finally, I ran a piece of abrasive cord through the valley between each tooth. Kind of like dental flossing! I was amazed at the amount of crud that I removed. The sharpened blade cut like new.

I would also try to rig up a clamp at the back of the table as well as the one at the front.

Roger
 
I haven't tried sharpening but oven cleaner works great for cleaning off that brown crap that builds up. When you say "small stone sharpening file" you aren't meaning a steel file are you?
"I would also try to rig up a clamp at the back of the table as well as the one at the front."
Funny you should say that. While I had the saw apart I did a couple of upgrades. One was to rig up a dial indicator so I can measure the blade position better. In the picture you can see the adjusting knob, I replaced it with the dial indicator. When I was testing the saw, about halfway through the cut I saw the indicator move about ten thou. I jury rigged a clamp for the back and did another cut and it was 40 thou in and 38 thou out. I think that's the problem. Everything is kind of cobbled together at the moment but we'll see how it goes tomorrow. I'm beat now.
 
Don, a comma might clarify things. It, should read: Using a small triangular sharpening stone, sharpen each tooth.

I would not use a triangular file. Instead I would use a small triangular sharpening stone. You should be able to find one at a hardware store. Unlike a triangular file with 60 degree angles, these have a 30 degree angle. A fairly light touch should be enough.

Roger
 
Y.T. said:
Which tooth surface are you sharpening. There are at least 4 surfaces on each tooth. Is this the surface you work on?

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that looks like a carbide tip circular saw blade ... not what i think the op was refering to as a slitting blade. your blade is available at home depot for $10. sharpening slitting blades has never worked well for me. note a rip blade doesnt have the same kerf as a circular saw combination blade.
 
My Thurston blade is 4" 80 tooth. I can't imagine a stone small enough to reach in there lasting very long. I can see it breaking on the first stroke. Are there super strength stones out there.

Anyway I got the saw improved a bunch. Improvements while I was in there include a rear clamp, a dial indicator for cut width and a screw adjust for cut width. It's a lot easier to set up now.

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I have a Byrnes saw. I bought when it first came out, probably 25 years ago. For the first half of it’s life it was an unhappy marriage; stalling during a cut, kickbacks, burnt wood edges, etc. 10 or so years ago, I decided to do something about it.

I did two things. First I aligned the fence using a dial indicator attached to the miter gauge. Unexpectedly I found that the rear clamp was pulling the fence out of alignment. Second I sharpened the blades as I described earlier. I have two Thurston slitting blades. I believe that they are 3” dia. 94 teeth. These do not have set teeth like an ordinary table saw blade, so a misaligned fence will pinch the blade against the side of the kerf and either stall the saw or burn the wood. The fence must be parallel to the blade within thousands of an inch or cm.

Re sharpening stone; If you go to Amazon and look up triangular sharpening stones you will find dozens to choose from. If you’re not an Amazon Shopper, any well stocked hardware store should have some.

Roger
 
Roger Pellett said:
Second I sharpened the blades as I described earlier.
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Hi, Roger. Sorry I believe you did not describe neither the how you sharpen the teeth (which surface of the tooth?) nor I saw no picture of the blade you have. I am afraid I might be not familiar with the terms you are using. Could you please post?
 
YT: These small Thurston blades are entirely different from the blade that you show above. They are actually made to cut metal when used in a milling machine. I’ll be in my workshop tomorrow and will take a picture of one. My sharpening technique will then be obvious.

Roger
 
I hope that the two photos posted below will clear up the confusion regarding sharpening of the blades used in my Byrnes and other miniature table saws. My all purpose blade is a Thurston I-192; similar to the blades shown in the first photo except cutting a .030” kerf. With the models that I build I seldom need to cut planking. I mostly use the saw for cutting sheet brass and for building fixtures for, holding metal for soldering. .030” is approximately 1in at 1:32 scale and 3 in at 1:96 scale; scales that I usually work to.

The second photo shows the triangular sharpening stone that I use fitted into one of the saw teeth. The stone is an equilateral triangle, each leg is 1/4” wide but any stone with an equilateral cross section will work.

Both photos show a very simple plywood fixture that I made to hold the blade while it is being sharpened. It clamps into a smooth jawed vice and helps me know which tooth has been sharpened

Roger











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Thank you Roger for good explanation. Unfortunately I did not find similar slitting blade which will fit on my Proxxon FAT saw. I need 10 mm arbor and 85 mm maximum outer diameter.
 
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