Ultra-thin sawplate....

**IanW** · 24th February 2011, 12:47 PM

A certain Forum member who shall remain nameless is determined to help me (not) kick this sawmaking addiction.

There has been the odd mention of making dovetail saws from plate thinner than the more conventional 0.5mm that is currently popular, & I confessed to being curious myself, about how it might perform. Well, this nasty man tempted me with some thin steel (15 thou" or approx 0.35mm when cleaned & polished), so what could I do???

Yes; – I just made another saw.

This saw represents most of what I have learned about sawmaking these last few years. After fiddling with various tooth profiles, I’ve abandoned my ‘hybrid’ teeth for small-toothed saws that will be cutting almost exclusively with the grain, because they perform slightly less well ripping than a straight rip pattern, all else being equal, and with so many saws to choose from, it's just as easy for me to keep a small crosscut handy for the cross-cuts. So my preferred dovetail tooth profile ATM is 15 tpi, with about 5-8 degrees of negative rake, & filed straight across. These will cut quickly & smoothly in most woods between about 10 & 18mm thick, and are no problem to start.

I have also tried to make a more ‘universal’ handle. If you compare the two saws in the first pic, the top one is the new saw (She-oak handle) and the bottom one, from 0.5mm plate & with a fiddleback Myall handle, was made to fit my hand, very snugly. The new handle has a more upswept top horn, and both bottom horns are a bit stubbier & less curved. So the new handle still sits ok in my own hand, but should be more comfy to hold in larger mits. I have kept the same grip angle, which is more ‘vertical’ than the L-Ns & other commercial saws I’ve handled recently. This is more suited to dovetail cutting, where you are generally working well above bench height, with forearm either horizontal or pointing up a bit. The grip angle on the L-Ns is ideal for use at bench height. I also cranked the cheeks of the new handle down more, to keep the handle slightly above the tooth line, whereas it sits slightly below on the older saw. In practice, that makes little difference, unless you want to use it at bench level, where the handle might catch, but it does get my hand up just a bit higher, and gives a slightly better sight-line of the teeth, without losing a direct ‘feel’ on the push stroke.

So what you all want to know is, how does it perform? Well, it’s action is nice, and has a different feel from the 20 thou saw, which is slightly heavier, but you would need accurate scales to pick the difference. These are ‘light’ saws for smallish work (medium to small drawers & boxes). I used 3/16 x 3/4” brass for the spines. I find that weighty enough & stiff enough for saws up to this size. The ‘test piece’ (second pic) is a bit of wattle, medium hard, & about 10mm thick. Both saws cut smoothly & quickly, but in this simple test, the thicker saw actually cut deeper for the same number of strokes (!) – the two outer cuts are the .5mm blade and have gone slightly below the line on both sides. The kerf widths, as near as I can measure with my rather manky feeler gauge (must get a new one!) are 0.425 and 0.6mm respectively. With my fresh, sharp saw I was easily able to cut an apex (centre) that is barely wider than the saw kerf (not that I would make such silly fragile pins on a regular basis, but there are those that do...

)

What has this shown me? Well, for one, there is more to speed of cut than blade thickness alone (of course!). Because these saws have hand-cut teeth, they are probably not identical in rake (though they ought to be damn close). However, I suspect it has more to do with set than anything else. It is really hard to set these small teeth accurately & as finely as I would like. So I do the finest set I can, then wipe off the ‘excess’ with a diamond stone. There is going to be some variation because it’s not easy to do an exact ‘wipe’ every time, though I must be getting fairly consistent, because both these saws tracked true without any adjustment. I suspect I have wiped away a slightly higher proportion of the tooth on the thinner saw, so there is less cutting width on the top of each tooth – all theory, of course.

It was a fun exercise, but will I switch to 0.35mm plate for dovetail saws from now on? Nope, I reckon the thinner plate is good for special saws, but would NOT be good in the hands of a novice, for instance, as it would run a high risk of kinking. The 0.5mm plate is a bit more robust, but even it would be easy enough to damage with rough handling. Going on this saw, I don’t think you could push the blade size much wider or longer than I’ve done on this (push) saw, either. The spine only just holds the blade straight at the width I’ve used (60mm at the handle end, 50 at the toe, & 220mm long). I could use a stiffer (1/4”) spine, & might try that sometime, but I find it unbalances a small saw if the spine is too heavy, which is why I used the 3/16" in the first place.

I also made a small 20 tpi ‘nipping’ saw from the cutoff of the d-tail saw blade (pic 3) (Why not? - I had a 'spare' Qld Walnut handle ready to go.

). This shorter & narrower blade is kept plenty stiff by the 3/16” spine, so I’d say the most ideal application for the ultra-thin plate will be saws for boxmakers & people who like to do intricate work....

Sorry for the long post, but I feel better now .....

Cheers,

**jimbur** · 24th February 2011, 01:00 PM

beautiful Ian, it's made my eyes water. I'm still recovering after sharpening a 20tpi - really must get back to the opticians.
Cheers,
Jim

**IanW** · 24th February 2011, 02:16 PM

Originally Posted by jimbur

beautiful Ian, it's made my eyes water. I'm still recovering after sharpening a 20tpi - really must get back to the opticians.
Cheers,
Jim

Jim - I need glasses just to see the damn saw, now! I couldn't do any saw-sharpening nowadays without the headband magnifier (X5). Twenty tpi is the practical limit of what I can tolerate forming & sharpening, & I have to concentrate like hell when sharpening such fine teeth, to be sure I skip only one tooth each time, & not two! The trick I learnt from RayG, is to use a fine felt-pen to put a dob on every second tooth before setting & sharpening. That helps a lot, with both operations. It is easier to not get out of synch when setting, & when I get to sharpening, I file the unmarked teeth first, so the contrast between the freshly cut metal & the coloured tooth really stands out & makes it much easier on the last pass.

Fortunately, I have no need of anything finer than 20 tpi for the sort of work I do, though both my small saws (18 & 20-tooth) do get a fair bit of use. If I ever get into dollhouse furniture, & need finer, I'll have to get a 10X loupe, but you have to stick your head so close to the job, I recon there would be quite a few file-marks on my nose...!

Cheers,

**Woodwould** · 24th February 2011, 03:28 PM

Lovely stuff as usual.

**RayG** · 24th February 2011, 04:25 PM

Hi Ian,

Congratulations on a beautifully made saw, excellent inspiration for me to get that 15 thou DT saw I've been meaning to make...

Another great write up and your conclusions are in-line with my thoughts.

The only thing that surprised me a little in your tests, was that the 20thou plate cut a little faster than the 15thou, I would have expected the opposite. 8 degrees rake is a little too relaxed for my taste. But speed of cut is not really a major consideration for cutting small joints.

Regards
Ray

**IanW** · 24th February 2011, 05:00 PM

Originally Posted by RayG

......The only thing that surprised me a little in your tests, was that the 20thou plate cut a little faster than the 15thou, I would have expected the opposite....

Ray - surprised me, at first, too! But remember it's just two cuts in one piece of wood with two hand-formed saws, & there was little in it (though surprisingly even each side). There are too many variables to make any conclusions from such a simple run. I could repeat this tomorrow & get the opposite result, & that wouldn't surprise me.

But to throw a cat among the pigeons, could someone please explain to me why a thinner saw SHOULD cut any faster or slower than a thicker one, if they have exactly the same tooth pitch & tooth profile?? I've been musing about this all afternoon, & it seems to my logic, they should cut the same depth per stroke, but with a little more effort required per stroke for the thicker one...

Originally Posted by RayG

...... 8 degrees rake is a little too relaxed for my taste. But speed of cut is not really a major consideration for cutting small joints.

Yeah, well, again, when I say 'between 5 & 8' it's probably closer to 5 than 8 - darned hard to measure accurately over such a short distance.

I'm still mucking about with rake angles, & unless I do some really well-controlled comparisons, I suspect I will just keep mucking about forever. Over the last 6-8 months, I've been moving towards larger teeth than I used to prefer on smaller saws. You can get away with a pretty rough sharpening job on small teeth (I did, for years! ) but I quickly discovered that big bitey teeth are much more fussy about things like evenness & how much rake you give them. Sure, an aggressive rake will chomp through softer woods in a hurry, but it also tends to catch & be hard to start in harder woods. I found there was a huge difference in smoothness of cut, & just a few degrees difference, on say a 12 tpi saw. On 15 tpi & above, you can just about stand that leading edge up vertically & get away with a saw that cuts ok, albeit a bit roughly, but I found with my bigger 'halfbacks' that I needed to back off to more like 10-12 degrees (for crosscut profile, that is). And a 10 tpi tenon rip I made was much too aggressive at 5 degrees. When cutting large tenons in Spotted Gum, it would shudder & catch as I briought the saw level to square the cut (i.e. cut straight across the grain) but became very happy once I eased it back a bit more.

In both cases I am still using rake angles that are towards the steeper end of what my guide recommends....

One of these days soon, we simply must get a bunch of keen saw makers & users together for a saw-off & sort some of these finer details out properly...

Cheers,

**planemaker** · 24th February 2011, 10:13 PM

Excellent tutorial Ian. Its worries me that you will slide so far down the slope you may find it extremely difficult to return to some normality. It is quite surprising that you can communicate too this "forum member responsible", and express no obvious verbal malice towards him. "Hang him by his shirt tails" I hear the mob demand...... Lovely work on those DTs Ian. It takes me 3 to 4 days just to shape 1 closed handle. You seem to flick these completed backsaws out like they were were just pancakes.

Stewie.

**RayG** · 25th February 2011, 07:04 AM

Originally Posted by planemaker

Excellent tutorial Ian. Its worries me that you will slide so far down the slope you may find it extremely difficult to return to some normality. It is quite surprising that you can communicate too this "forum member responsible", and express no obvious verbal malice towards him. "Hang him by his shirt tails" I hear the mob demand...... Lovely work on those DTs Ian. It takes me 3 to 4 days just to shape 1 closed handle. You seem to flick these completed backsaws out like they were were just pancakes.

Stewie.

Hi Stewie....

thanks for the warning, I'll keep my head down for a bit...

(After I post yours that is..)

Regards
Ray

**IanW** · 25th February 2011, 08:29 AM

Originally Posted by planemaker

.....It is quite surprising that you can communicate to this "forum member responsible", and express no obvious verbal malice towards him. "Hang him by his shirt tails" I hear the mob demand......

Ah Stewie - I think he means well....

And to be fair, you could have chastised me for being so weak & not just putting the stuff in a drawer til I finished some of the more pressing jobs I'm supposed to be doing.

Originally Posted by planemaker

..... It takes me 3 to 4 days just to shape 1 closed handle. You seem to flick these completed backsaws out like they were were just pancakes.

Well, it took me about the same time to make my first couple of handles, too. I've got it down to about a day or less to make a saw if I get a clear go at it, but that's still a long way from a commercial proposition!

Now that we are on the topic, I have been musing about what would be involved in making saws for sale. I was talking with Terry Gordon at the hand tool Expo they held here in Brisbane last year, & he said he would be delighted to be able to offer high quality locally-made saws instead of all imports. I reckon a relatively small investment in some machinery would allow you to do the repetitive stuff like preparing & toothing blades - setting & hand sharpening takes very little time on a well-prepared blade. You could automate cutting out handle blanks, drilling for screws, and slotting them for blade & spline, but the only way to get a truly decent handle is to hand-shape the complex bits. I guess you could get pretty slick at it if you did it often enough, reducing production time to something like a couple of hours each, perhaps, so it could be done at a competitive price. I even seriously considered the possibility of starting a new career, one night, but after the second beer, sanity & clarity of thought returned....

Avagooday,

**Woodwould** · 25th February 2011, 08:50 AM

What brand name have you registered?

**IanW** · 25th February 2011, 09:03 AM

Originally Posted by Woodwould

What brand name have you registered?

Another Forumite has suggested "Wilkut".

**Woodwould** · 25th February 2011, 09:15 AM

Originally Posted by IanW

Another Forumite has suggested "Wilkut".

I think a saw making business would suit you down to the ground; you've perfected the necessary skills, you're in dire need of occupation now and who could resist a new saw with a pretty handle?

I don't qualify as a customer because I didn't pay for my saw, but I'll gladly write a spiel for your 'happy customers' page on your new web site!

**Tink** · 25th February 2011, 09:42 AM

Where does one buy thin polished saw plate in Australia?

**jimbur** · 25th February 2011, 11:20 AM

Just tossing in an idea about why a thick plate saw should cut faster than a thin plate.
Could it be as simple as gravity? Assuming you let the saws do the work, perhaps the heavier saw 'forces' a deeper cut each time.
As I said, it's just a thought.
Cheers,
Jim
ps there must be a patient market out there for good hand-made tools. Look how long Derek waited for his Japanese chisels!

**jimbur** · 25th February 2011, 11:22 AM

pps. never make a decision after the second beer. Go for a third, fourth or fifth until things make sense

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