Problem sharpening old saws

[overland]

Recently I began sharpening up a few of the vintage back saws I have in my possession. In most cases the teeth aren't just dull but uneven. How do I get them back to the same shape and height? Obviously jointing the saw alone won't do it.

[Anji12305]

If your backsaws are like mine, the teeth are fine - too fine to clearly see without magnification. In the link below, note that shaping the teeth isn't intended to produce a tooth with a sharp point.

It's intended to produce a tooth with the same size flat spot at the apex, as all the rest.

Final sharpening will bring things to a cutting edge.

Remember that the important aspect you're trying to achieve in the first sharpening is a saw that tracks straight - not necessarily one that cuts super fast.

Joint/Shape/Set/Sharpen

"File just enough so that you can see a flat spot forming on all of the teeth - if there are one or two that aren't, it's not a big deal - subsequent sharpenings will bring them out. But only a couple... "

http://norsewoodsmith.com/content/sharpening-hand-saws

[MarvW]

Here is the best video on saw sharpening I've seen. This video focuses on filing a rip saw. He shows in good detail how to reshape the teeth and to then set and file the teeth.
Filing and sharpening a rip saw

[overland]

Excellent video. I see now where I've been going wrong--not devoting enough time to shaping the tooth as separate from sharpening. Thank you.

[Dakotapix]

Excellent video, Marv. Same here regarding the initial shaping before sharpening. I have a couple saws that I'll need to joint and shape three or more times, as in this video, before I start sharpening.

[Admiral]

It can and does require multiple shaping sessions, but once you've gotten the teeth rehabbed, then sharpened, maintenance gets pretty easy.

[Jonathan S]

I did one a year or so back that was so hollow in the center, I went through 5 or 6 joint - shape iterations before I got a straight toothline with all the teeth the same height. Burned a couple of files on that saw.

Jonathan

[MarvW]

It's by far the best instructional saw filing video I've seen. However, I have to question the use of the Somax saw sets. You can file and sharpen a saw to perfection, but if you don't set the teeth properly, the saw will not perform at it's optimum. The Somax will tend to over-set the teeth. You want only enough set so your saw won't drag or bind in the kerf. Some old saws will require a lot of filing to get the teeth all the same size and shape. It's a tragedy to spend all that time just to end up with a saw that cuts rough due to too much set. To reduce set, it's best to file the teeth until the set is right. A beginner might not realize why their saw is cutting so crappy. Setting the teeth seems like such a simple step in the whole process, and in fact it is, as long as you follow a few simple rules. Use a saw set that is easily adjustable in minute increments and will not move during the actual setting of a tooth. The saw set that comes the closest to fitting these requirements is the Stanley 42X.

For those of you who might not be familiar with this saw set, here's what it looks like.


I use two of these. One I modified for the smaller teeth. 14 or 15PPI and smaller. To modify, grind the two front edges of the plunger at an angle to reduce the width of the front surface that presses against the teeth.

This saw set is usually available on eBay or often times being offered here on WN down in the S&S department. A fair price for a good one is around $40 +/- I've seen them in new condition such as the one in the above picture for upwards of $85 or more.