Saw Chatter what causes it?

[Todd Chamberlain]

What causes saw chatter when you cut? It is as if the saw does not want to in gauge the wood, each tooth rides over it. One more question what causes the saw to bind as you get deeper into a cut? Thank you for your information.



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[john brenton]

The first can be bad tooth geometry or sharpness, or both.

The second is most likely the set. I say most likely because a saw can bind with good set too. You may want to look at your technique. It's better to have very little set and better technique than to have less than good technique and lots of set.

[Peter Cobb]

Agree with what John says.

The other factor is moisture content. Saws bind because the "slot" (kerf) the saw makes closes up above the teeth or the saw "clings" to the walls of the cut (sticky walls, rusty saws, a kink, metal expansion due to heat, etc. all influence the cut). Really damp softwoods will bind any "no or low-set" saw quite soon cut because the saw may not so much cut, but tear and compress the fibers allowing them to spring back behind/above the teeth.

The "optimal setup" for the saw is based on the type of wood, its thickness and moisture content and your arm length and upper body strength. (info garnered from SMC, Mark Harrel's Bad axe site, and Ron Herman's articles and videos. So, as the saying goes, you have a good reason (need) to have several saws :D:D!

As a beginner I've opted to average out (not enough saws, yet) and accept I sometimes don't have the optimum. The main problem I had at the beginning was trying to use an unfit saw (blunt as a butter knife, and FAR to fine (high number of Teeth per inch) which is rather like using a nailbrush to sweep your shop out, it'll work but it's not the sensible tool for the job).

Vintage saws sharpening primer (http://www.vintagesaws.com/library/primer/sharp.html) and TFWW sawtooth design tables (http://www.toolsforworkingwood.com/Merchant/merchant.mvc?Screen=NEXT&StoreCode=toolstore&nextpage=/extra/blogpage.html&BlogID=86) explain a lot of things really well.

Hope that helps.
Cheers,
Peter

[Randy Bonella]

Hi Todd
One other reason, not mentioned yet, could be technique. After being observed by Mike Wenzloff when testing some of his saws, my chatter was generated by to much down force on the blade. once I just let the mass of the saw do the work, no extra down force, not only did the saw cut smoother it cut faster. It was amazing how it changed my ability to cut straight lines and increase the speed of my cuts. If the saw is sharp with a good set then this might just do the trick.

Good luck.
Randy...

[Jim Koepke]

Howdy Todd and welcome to the Creek.

Your location information is not in your profile. If you live anywhere near me let me know. I am happy to meet other woodworkers and to help them with their use and understanding of hand tools.

There are many things that can be taking place with your sawing.

Here in the Pacific North West we have a lot of fir. Often it is not as dry as would be preferable for woodworking. I have sawn across 2X3s that pinch my saw before getting all the way through a cut.

On the other side of that is having a saw with generous set rattling in the cut on the back stroke in dry hardwood.

The information needed to help with solving your situation would include the type of wood you are cutting, whether you are cutting cross cut (across the grain) or rip cut (with the grain) and the type of saw you are using.

Other information to help would be about the saw. Is it a new saw or an old saw? Was it recently sharpened?

I have sharpened a few saws and had some success. It seems each time one of my saws is sharpened I learn about another mistake that can be made while sharpening a saw. Hopefully the day will come when I will have committed every possible mistake, learned from it and then move on to being good at sharpening saws.

If the saw teeth are rolling over the wood without doing any work, my first guess would be the teeth are either dull or there is too much rake.

Close inspection with a magnifier will determine if the tips of the teeth are not sharp.

Rake is the angle of the front face of the tooth in relation to the line formed by the tips of the teeth. With the teeth facing up, the point of the tooth should have a slight slant towards the handle, the point of the tooth will be behind the base of the tooth. For rip saws the most this is angled is about 8 degrees. For crosscut saws this angle is usually at most 15 degrees. The more the rake, the slower a saw will cut until it will not cut at all. Less rake makes for more aggressive cutting.

The sites Peter Cobb mentioned are very helpful in understanding the workings, or non-workings, of saws and the whys and wherefores of saw tooth geometry.

If the saw is binding and bouncing in the cut, some teeth may be doing all the work. We get a few common terms from the lore of sawyers. Out of joint comes to mind. I am wondering if the term snaggle tooth might also come from saw terminology. A tooth that is tall and out of joint can snag in a cut. Different arrangements of out of joint teeth will have different feels to the person working the saw.

Maybe some pictures of your saw with close ups on the teeth and what the cut looks like might help in your efforts toward sawing.

jtk

[Todd Chamberlain]

Thank you all for the information.

The type of saw I am using is a 14" Gramecy Sash Saw, it is brand new. I was cutting tenons with the grain in 8/4 soft maple, the saw would chatter for the first 3/4 " or so then it would stop. I'm new to traditional wood working and still learning all the angles on the saw and terms. I used my Veritas dovetail saw for a little bit to compare the two and it had no problems. I might be putting to much pressure not even realizing it.

I will try to getting some pictures of the teeth and post them. I will also look closely at the teeth with a magnifier as well.

Once again thanks for the information, it has been a help better understanding.

Todd

[Bob Strawn]

If the chatter is stopping, after you start cutting a bit, then it may be too few teeth in contact to start. The more teeth in contact, the slower the cut, and the smoother. When sawing thin wood it is hard to get enough teeth in contact to make it run smooth to start. When sawing on a corner, it is also hard to cut smoothy.

When I start a cut, I make a short backward stroke on a corner, to start my cut, but a lot of woodworkers will now hide their saws from me because I said that. Then I lower the angle to get as many teeth in contact as I think I can with the first reals stroke while still letting the initial notch guide me. If I am do a fine cut, I strike with a marking knife first and cut to the side of that mark. My first stroke does not even have the weight of the saw on it. It is a gentle kiss.

Bob

[Jessica Pierce-LaRose]

I believe the rake on the Gramercy saws is a little steeper, making them a little harder to start compared to your Veritas saw, until you get used to the tool. I think the Veritas is at 15 and the Gramercy at 4, but I could be pulling those numbers out of the air. As the others have said, ease up on the pressure if you aren't already.

The other thing, (and you probably know this) is to cut with the grain - pulling the saw down into the end grain is going top be harder than going over it. If you're just laying the saw on top of the end grain, that can be quite difficult to start a cut! Joel from TFWW describes this better here:

http://www.toolsforworkingwood.com/Merchant/merchant.mvc?Screen=NEXT&StoreCode=toolstore&nextpage=/extra/blogpage.html&BlogID=161

The canted blades on the Gramercy saws help with this, as does paying attention to which way you angle the stock in the vise when cutting across two lines.

[jamie shard]

If you gently put the palm of your hand on the teeth, do they feel like they grab the skin? Is it sharp?

You know, with really new/sharp saws, they will actually be too "grabby" until they dull just a little with use.

[Jim Koepke]

Try a Google search on > schwarz nibble < to find his post on "Not sawing, but nibbling" on his PWW blog.

My method is to hold the saw very lightly on the line and move it back an forth to get it started.

After posting this, a visit to Lost Art Press found another gem from the Schwarz. Search > "I Found a Use for my Lower Horn" < (include the quotes)
This may be one of those things that those of us who do not analyze all of this for a living may do without knowing.

Developing the method that works best for the person doing the work is just one part of the eternal quest.

jtk