Continued problems with rip cuts

[Jason Morgan]

In working on the router table I am building I needed to cut some thin strips of wood for edge banding. I have been having trouble with burning of cuts with my forrest WWII and thought, Ill fix that by buying a good dedicated rip blade. Well, the rip blade (Freud 22tooth glue line rip) is worse than the forrest. I notice a lot of "chatter" when I am making the cut. It requires a little more feed pressure, but has a lot of chatter. Its evident in the cut too (lots of arc line on the edge of the piece) I have checked, re-checked, and re-re-checked every alignment I can think of. Fence to blade, blade to table, fence to table etc. Could this be a belt issue? didnt think about this last night. I am using a link belt and notice from time to time that it gets loose and I need to take a link out. Could this be to blame?

[Howard Acheson]

Have you checked the sawblade alignment to the miter slot? The blade should be parallel to the miter slot to within no more than .003". Similarly, your fence should be parallel to the miter slot to the same tolerance.

How thin a strip are you trying to rip? How are you holding the board to the fence and down onto the table?

[Matt Tawes]

Hi Jason,

If you have a bandsaw I would just rip your banding stock on that as its safer (though I still do much of mine on a TS then drum sand to thickness). Narrow stock between the blade and fence almost always results in chatter and poor cut not to mention being unsafe. I usually rip small strips from the edge of a board (taking my strip from the offcut left side of blade)and just move the fence over for the next cut but then again I'm not depending on the saw fence to give me final thickness on my edgebanding.

[Rob Blaustein]

Are you sure the blades are flat? Have you checked for runout in the arbor? Though I would think these things wouldn't cause increased noise. It will be interesting to see what happens when you tighten the belt.

[John Lucas]

I think that Howard has the diagnosis pinned down. My guess is that the thin stock is not being held firmly just after it is cut. Try this, turn the board around and set the fence so thatt the thin waste strip is on the other side of the blade. If it is a good cut, then Howard's suggestions should rectify it and you should get a holddown on the thin piece at the blade point.
When I do cutting of thin strips, I use the two hold downs of the Grip Titie system with their steel fence add-on. I can let go of the stock at any point without kickback...that solid an approach also helps the quality of the cut. Both blades should have worked, but the rip blade is the right one for the job.

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[Matt Tawes]

Maybe we should ask...are you getting burning, rough cut and chatter on all your rip cuts or just when trying to cut narrow strips?

[Michael Ballent]

You have not mentioned the type of TS you are using, contractor, cabinet, bench top direct drive etc...
Have you checked your arbor to make sure that it's running true? First make sure that the business end of the plug for the TS is sitting right next to the blade. (Can't be too safe :D) You will need a way to hold the dial indicator in place as you spin the arbor. It should not show more that .001-.002 of runout. I would guess that another way to check it would be to place blade on and put the dial indicator against the body of the blade and spin it via the belt... If you are seeing movement on the dial indicator then you have isolated the problem to the blade is not true or the arbor could be bent.

[Jason Morgan]

TS is Powermatic 64A contractor type. Blade and miter slot are within 0.001", same with fence and miter slot but possibly more like 0.003". I measured the arbor runout at the arbor and it was just under 0.003". On the blade itself I am getting closer to 0.006" runout total (in a 360 revolution).

The problem is a LITTLE better when ripping wider stock, but not a lot. Still get burning and chatter. Funny thing though, when I rip really wide stuff, it cuts like butter. I was cutting panels for the router table and they wnet through with smooth cuts and not hint of burning or chatter. It still seems like something is getting pinched or restricted, but I cant figure out what it is.

Ill do some more sluthing and post what I find.

[Lee Schierer]

I notice a lot of "chatter" when I am making the cut. It requires a little more feed pressure, but has a lot of chatter. Its evident in the cut too (lots of arc line on the edge of the piece) I have checked, re-checked, and re-re-checked every alignment I can think of.

Chatter in my mind is caused by the board moving up and down as it is being cut. This can only happen if the board is not tight to the table at all times. If the top surface of your throat plate is below the surface of the table then a gap would exist that could cause the chatter. To check, lower the blade all the way and run your board onto the cut area. See if there is a gap between teh bottom of the board and the surface of the throat plate right where the blade would be cutting. If you see a gap, this is very bad. You can also press on the board right where the blade would becutting and if the board rocks it is also bad.

Most throat plates have ajustment screws to raise or lower the throat plate so it is exactly even with the table surface. You do not want the throat plate higher and definitely don't want it lower than the table surface. If this is a home made zero clearance insert then you need to make adjustments with shims. You can cut paper shims and glue them on if your insert is wood.

Make sure you blade is not raised too high. The blade should be no higher than the bottom of the gullets coming just above the top side of the board you are cutting.

It is possible that your throat plate is not stiff encough so it is flexing each time a tooth enters the top side of the wood. It may be necessary to add reinforcement to the underside to stiffen it up.

Place feather boards that press down close to the front edge of the blade to keep your fingers away from the blade and the board tight to the table.

Warped or bowed pieces may also cause chatter and should be avoided or trimmed so they are flat.

[Jason Morgan]

Well, it turns out that the only cure for a persistant rip problem when you have checked and rechecked the blade to fence alignment is to check the blade to fence face alignment. Sure enough, when the fence was set to 1-3" the back end was about 1/64 closer than the front. I reset it so that the back end was just a hair wider than the front and everything cuts like its supposed to. I did notice that I need to do something about my zero clearance insert. The one I am using is a piece of UHMW that has a pretty good bow in it. I think Lee has a point with the insert being flush. When mine is flush in the middle, the ends are below the table about 1/16".

Problem solved for now.

Thanks to everyone for the help.

[Rob Blaustein]

Jason,
I have had the same problem with my UHMW insert. You can put it on a table so half is off the table and exert pressure to bend it to straighten out. I seem to have to do that periodically. Apparently these are difficult to mill flat.
Rob

[Vaughn McMillan]

Same problem here when I tried using UHMW inserts. The bow made it impossible (for me) to get a clean, accurate cut, and both inserts I bought exhibited the problem. I tried cutting grooves in the bottom to release whatever stress was causing the bow, but I still coun't get them really flat. I switched to the blue laminate insert Rockler sells and get better results.

Also, for keeping thin rips in control while cutting them, the Grrripper sure helped me improve the quality of my cuts. (Anything narrower than about 1/4" I use the "waste" side of the blade, as John Lucas and others recommended. The Incra makes that pretty easy to do.)

- Vaughn

[skip gleichman]

I had this problem on my General saw and it was solved by going to a new belt... it was vibration that was the culprit in my case. I went with a link belt and now have smooth cuts and the saw sounds much smooter... just a thought.

[Bill Fields]

WOW! SMC rocks again!

I paid $39 to get on the Taunton website--and it is a few notches below this one in real time/realitysolutions.

Bill

[M. A. Espinoza]

TS is Powermatic 64A contractor type. Blade and miter slot are within 0.001", same with fence and miter slot but possibly more like 0.003". I measured the arbor runout at the arbor and it was just under 0.003". On the blade itself I am getting closer to 0.006" runout total (in a 360 revolution).

The problem is a LITTLE better when ripping wider stock, but not a lot. Still get burning and chatter. Funny thing though, when I rip really wide stuff, it cuts like butter. I was cutting panels for the router table and they wnet through with smooth cuts and not hint of burning or chatter. It still seems like something is getting pinched or restricted, but I cant figure out what it is.

Ill do some more sluthing and post what I find.

You haven't mentioned if you are using a splitter. If so I find that if I set the splitter so that it favors the fence side of the kerf it keeps thin rips from chattering. Just enough so there is pressure to keep it against the fence.

I also set the fence so that the teeth just clear on the back side of the cut. I do this by feel with a piece of fall-off. No slop, just enough so I know the teeth aren't catching on the back side of the cut.

Good luck.

[Charlie Plesums]

When you get past all the possible reasons, like type of blade, splitter, runout, etc., the bottom line is that the burning is caused by the wood rubbing against the blade after the cut is made.

I was sure my saw was aligned perfectly, but I was still often getting some burning when I ripped along the rip fence. Despite the conviction that the fence was perfectly aligned, I turned the adjusting screw to move the fence away from the blade...the smallest amount I could turn the screw. The burning went away completely. I don't know whether the problem was that the fence wasn't actually aligned perfectly, or whether the toe-out of the fence really is required (as some but not everyone believes), but I now get "perfect" cuts so I haven't looked back.