Wandering Crosscut

[Ellestad]

Why am I getting a "wandering" cut cross grain in dressed 4/4 hard maple?

The saw is a sharp 10 inch 60T ATB carbide (I don't remember the brand and it has been lost to cleanings and sharpenings). The total run-out wobble - arbor, collars and blade - is just under +/- .0025". Is that too much? The blade is parallel to the slot to within about .001" fore and aft on the exposed blade (I suspect that the slot isn't really cut to quite this accuracy).

The cuts are clean and smooth with no fringe but are ever so slightly "wavy" instead of a nice flat joint surface. This saw and blade has made nice straight cuts since the blade was last sharpened and nothing has changed to the setup except that the saw was put on a roller base - but I broke my back re-leveling it.

Thanks in advance for any ideas.

Tim

[Leon]

Possibly so..if that run out is at the arbor. At the teeth on the blade, no.

Could you have warped the table surface while putting the saw on that mobile base? Is that a thin kerf blade by any chance?

[John Crea]

Using a featherboard??? If not, it is possible that using one could nelp. I usually use a combo, one featherboard holding the work to the fence, and a couple holding the work down to the table

John

[KYHighlander]

he's cross cutting, how you use a featherboard crosscutting?

[Ellestad]

Hi John -

Thanks for your reply.

This is a cross-cut blade and I was using a heavy and well-proven miter gauge with the stock fixed to the fence.

[Ellestad]

Hi Leon -

Thanks for your response.

Yes, at the tooth point.

The surface looks good to a 24 inch blade that has proven very good.

No, old-time .125" or there-abouts.

Maybe I've messed up my history (I'm getting gray) and I didn't actually do anything critical to prove that it was working good since it was sharpened. Could this "wavy cut" be the result of a bad grind angle on the tooth face?

Tim

>

[Bridger]

I'd like to see how you position a featherboard for a crosscut.....

[Rob V]

Just an FYI - I get that "wavy" effect if I dont use a blade stablizer. But I am using a thin kerf blade and I see that you are not.

May be worth the $10.00 to give it a shot just to see.

When you make the cut - actually look at the blade and go slow - see if you see it flex at all.

[David Merrill]

I had a wandering cut problem with a hand-held circular saw while cutting the bottom of door blanks. It was a little used, carbide tipped blade. Checked all the alignments and was left scratching my head until I finally took off the blade and set it on a flat surface, first on one side then on the other. A slight but noticeable dishing of the blade disk was apparent. This was an inexpensive blade (B&D Piranah) without thermal expansion slots. I suspect that the blade had overheated in the thick door blanks and warped. Does the blade in your table saw have thermal expansion slots? Has it possible warped?

David Merrill

[Ellestad]

Thanks Rob -

I have blade stabilizers and I wasn't using them. I'll give it a shot.

Tim

[Ellestad]

Thanks David -

I'll give it a look. The expansion slots might be suspect on this blade because when I first got this blade (back in pre-history) it was a miserable screamer. The guy who sharpened my blades made loose plugs for the expansion holes (note- I said "holes") that worked well back then and silenced the siren. Maybe they are now stuck and no longer allow the blade to vent. Thanks for the idea.

Tim

[Morris Dovey]

Here we go again...

As a push stick?

[Bob Davis]

How did you do that? You didn't just try to pick it up without a lever or a jack did you? I leveled my 400 lb. Supersaw while I had 3 herniated disks, but I used six foot long boards as levers. It was a stupid thing to do anyway, but it didn't hurt much.

Bob

[Eric Ryder]

Any burning? It sounds like a hot blade, causes that come to mind are dull and/or no set.

[jev]

How close to end of piece are you cross- cutting. This problem occasionally pops up if you try to take thin cuts off the end. Caused(I assume) by the fact that blade has more room to vibrate since it's less constrained on the thin end.

[Ellestad]

Thanks Eric -

No burning, no burnishing. Just smooth and slightly "wavy".

This "wandering" gets going quickly, too, I might add. The try square looks bad on a 3 inch cut.

Tim

[Ellestad]

Thanks jev -

My cut-offs were three inches. I have seen what you are describing when triming off, say, a quarter inch or so.

I'm doing a blade comparison now.

Tim

[Larry Jaques]

On Thu, 12 Feb 2004 18:17:45 -0600, "Ellestad" brought forth from the murky depths:

Then you're probably forcing it into the blade and flexing the miter gauge. After making sure the miter gauge is not sloppy in its fit to the saw top, try a gentler, slower cutting motion. Since higher-tooth- count blades have smaller gullets, give them more time to clear their sawdust with a slower cut.

[Nate B]

"Ellestad"

So I just read this thread. Very interesting. I'm in the disk drive industry and know quite a bit about plate vibration, but not as much about woodworking.

If you are getting waves after sharpening, then I believe you have found your problem - and it makes the most sense to me out of everything I just read. What little I know about the actual sharpening process tells me that the edges of your teeth may now resemble a roller coaster as you travel around the circumference of the blade. That would set up some plate vibration modes and bending.

Certainly you have another blade laying around you could swap out and test this theory with. Preferably one that hasn't visited this particular sharpener.

Let us know how it turns out.

- Nate

[patrick mitchel]

Same thing in other wood? I'd be tempted to make a crosscut sled. Pat