A handsaw for plywood only

[MikeG.]

I have a couple of spare handsaws awaiting restoration. At the moment I am cutting rather a lot of ply, and it has crossed my mind that one of the saws, which has virtually no teeth, might be worth filing smooth and re-cutting to suit the nasty lightweight splintery Far Eastern plywood which seems ubiquitous at the moment. I was thinking of something like 12 TPI with a crosscut pattern, lots of fleam...but I'm really not sure about that. The idea is to reduce the amount of spelching on the bottom face, and speed of cut isn't terribly important.

So, does anyone have any thoughts on what pattern to file the teeth?

 

[Blackswanwood]

Just thinking about this (which means am probably wrong!) isn’t the rake more important than the fleam for this? I find when cutting plywood keeping the angle of the saw low gets a better finish so having positive rake must help?

 

[MikeG.]

Yep, that's certainly true....and a useful thought.

 

[Blackswanwood]

Just in case anyone else reads this thread and like me finds saw sharpening a bit of a minefield I found this last year and it helped me get my head around it

https://toolsforworkingwood.com/blogimg/sawspectra.pdf

 

[D_W]

I have a couple of spare handsaws awaiting restoration. At the moment I am cutting rather a lot of ply, and it has crossed my mind that one of the saws, which has virtually no teeth, might be worth filing smooth and re-cutting to suit the nasty lightweight splintery Far Eastern plywood which seems ubiquitous at the moment. I was thinking of something like 12 TPI with a crosscut pattern, lots of fleam...but I'm really not sure about that. The idea is to reduce the amount of spelching on the bottom face, and speed of cut isn't terribly important.

So, does anyone have any thoughts on what pattern to file the teeth?

I have a 26" old spear and jackson crosscut saw that I've used to cut plywood. The ply that I cut is generally hardwood face with fir core and almost no glue line, so it's easy on the saw. Works great.

It's 12 TPI, and was originally, as you're guessing. It has normal fleam - I don't think you want so much fleam that the saw rasps in the cut or it'll be really slow.

When I did my kitchen, I cut a fair amount of the plywood with it, and the entire last corner diagonal cabinet which I made the box and all parts except the door (to match the other doors - used a router bit set for the door coping and panel) entirely by hand. I don't have power tools good enoguh to do that kind of oddball cabinet accurately.

At any rate, I'd go with a normal fleam setup (which depends somewhat on rake, too) first and only add more if needed. It'd be no more work to do that than it would be to push the fleam to a drastic point, anyway. Half of your cut is going to be rip and half crosscut - you'll appreciate that the saw cuts on its own and the cut accuracy will be better for it. You can pretty much cut on the cut line and just use the panels right off of the saw.

Break out was no worse than a power saw for mine (I cut most of the rest of the ply with a makita SP6000 laying on a foam insulation backer.

 

[D_W]

Just thinking about this (which means am probably wrong!) isn’t the rake more important than the fleam for this? I find when cutting plywood keeping the angle of the saw low gets a better finish so having positive rake must help?

Both rake and fleam work in combination to determine how much blowout is on the back side of a cut. too much rake or too much fleam can both create a slow cutting saw. It's normally better to just go to a finer tooth with normal rake and fleam than it is to relax a saw's rake too much (no bite without you leaning on the saw) or get drastic with fleam (rasping in a cut and not pushing fibers out efficiently - just riding in grooves that the points of the teeth cut until you really lean on the saw).

 

[MikeG.]

........ I'd go with a normal fleam setup (which depends somewhat on rake, too) first and only add more if needed. It'd be no more work to do that than it would be to push the fleam to a drastic point, anyway. Half of your cut is going to be rip and half crosscut - you'll appreciate that the saw cuts on its own and the cut accuracy will be better for it. You can pretty much cut on the cut line and just use the panels right off of the saw.

Thanks very much DW. I take it yours just has a normal cross-cut rake, then?

 

[D_W]

Thanks very much DW. I take it yours just has a normal cross-cut rake, then?

Yes, I don't know the exact amounts off of the top of my head, but probably something like 15 degrees of rake and 20 fleam or maybe slightly more fleam. I use the saw for hardwood crosscuts, also, where the back side of the cut matters. It only gets resharpened once every four or five years, so I don't remember how it's set, and when I resharpen, I don't have gauges or gadgets - if the saw is cutting fine, I file the teeth at their shape and get on with it. But, there's nothing unusual about the setup and I filed it when I first started working mostly to entirely by hand (Since then, I've started to file crosscut saws more aggressively so that they're easier working -there's only a need to have one fine tooth saw with lots of fleam).

 

[MikeG.]

Thanks.

 

[Hornbeam]

I often use a larger tennon saw for cutting ply . 12 tpi cross cut angled so the back doesnt catch so as well as tpi I think the shallower the angle and so the greater apparent thickness (more teeth in the cut) are important
Ian