Thread: Used Irwin Tenon Saw Blades

Originally Posted by RayG

.....Is that the same D9, from a short while back?, or have you snuck in and whipped up another, while my back was turned.... ]

Err, arr, well, - I've ended up making 3 of them, in all.....

Yeah, I know I said I was quitting, but people keep tempting me - I had to play with Kevjed's castoff Irwins just to see what the metal was like. The thought of all that potential sawmaking material going to the tip was too much!

I actually snuck the saw into this thread, where I compared the difference in cutting rates for different thickness blades:

https://www.woodworkforums.com/f44/comparisons-1-a-102410

As it turned out, there was surprisingly little difference, though as I said, it was hardly a very exhaustive comparison - I think factors like saw weight & balance contribute a lot to cutting rate as well as tooth patterns & pitch (& these are very personal & subjective qualities). There is more to learn about this sawmaking business than my limited abilities can cope with!

Originally Posted by RayG

......
PS. I attempted a progressive pitch filing guide.. not very successful, but I might see if it can be refined somehow.

Yes, I looked at that a while back, it was what got me started on the idea (you are a very bad influence!!). But are we talking about the same thing? Your guide is for progressive rake, but I went for altered pitch on this saw. Not really "progressive" - that's too hard, just 25mm or so of finer pitch, then jump to the main pitch. Someday, when my filing skill is up to it I would like to try a real progressive pitch, where each tooth is fractionally bigger until you get up to the size for the rest of the blade.

I decided to give progressive rake a go, too, on a recent saw - that seemed a lot easier. But protractors & bits of string are too complicated for me, so I varied my simple filing guide that I use when cutting teeth to depth - a short piece of wood with the file jammed in so that when the stick is horizontal, the side of the file is at the right rake angle. By leaning the stick right over at the start, then gradually bringing it back to level over about 25mm, you get a gradual increase from a very laid-back angle to the one you want for the main body of the saw. Only tried it on a 10tpi ripsaw, so far, as that seemed the most appropriate, and it works very well. I am thinking of applying the same treatment to my big S&J ripsaw, next time I sharpen it, as it can be a right beast to start sometimes.

I really have quit sawmaking for the while. I am stuck into a Qld Maple desk that has been languishing for a couple of years, due to all sorts of reasons, but it is coming along nicely, now, and I would like to get it ready to polish before the weather turns too hot & sticky for French polishing. I am using 3 of my own-made saws a lot, and enjoying them immensely. Trying to figure out which of the ones I've made to hang on to, & which to part with (can't fit them all in my toolbox!). So far, my favourites are a "D9" carcase saw from the thinner (.6mm) Bunnies scraper, and a really delightful little dovetail from the 1095 (.5mm) stock you sent me. These two are definite keepers!

Cheers,

Hi Ian,

We are talking rip of course....

I meant progressive rake, not progressive pitch. But to be honest, I haven't managed to make a decision either way, I think that what works best is to "relax" the rake a little at the front, but I'm thinking it's fairly slight, only a few degrees.

But the problem, is testing if someone else finds it easier to start, half the time I can't tell. And once you have the cut started it doesn't make much difference.

The problem with progressive pitch is that at some point of time, the saw will be sharpened by someone else, and there is no way to easily specify how it should be done. So the best compromise is probably constant pitch, and ease off on the rake a bit towards the front of the saw. But I have no hard and fast data to support this.

Interesting subject...

Regards
Ray

Hi again Ray,
Yes, ok, we are on the same page. I agree with you that it is very subjective when assessing the effect of varying either pitch or rake for easier starting - best way would be to blindfold someone & hand them two saws identical but for the front teeth & see if they can tell which is which in use!

I freely admit it was the idea that attracted me - seemed like a fun thing to try, & no harm done other than a couple of mm of metal to file off if it was a disaster. I do think relaxing the rake (that's a good term you used for it) on the 10 tpi rip worked well, and is easy to feel. Not so sure dropping the pitch on the crosscuts did a lot for starting a crossgrain cut, but I think it makes quite a difference in making a very accurate start on an end-grain cut. F'rinstance I frequently cut diagonals to engage the drive spurs on the end of turning blanks, which need to be as accurate as possible, & my new double-pitch saw does a grand job, there.

However, like you, I'm wary about my objectivity (or lack of it) in judging such things. The fact that you are using a tool of your own making is very likely to influence your judgement positively, & if you think you have just added a special flourish, your brain is going to take a lot of convincing it isn't the bees' knees.

As to future sharpening - well, that isn't going to be a concern of ours, is it? Neither altered rake nor altered pitch can be handled automatically by any current machine - they can't even cope with fleam. The average Joe operator wouldn't notice if there was any variation - they will be plonked on the sharpener and the switch flicked on. So these are going to have to either remain enthusiasts tools, or get machine sharpened (shudder!), after I'm gone - I'll just have to get used to rolling in my grave --
Maybe there'll be a few out there who preserve the art of saw filing (if they can still buy files - looks like we are down to one accesible supplier of DEST 4" files in the country).........
Cheers,