Thread: Magnification

These are from Andrew's Disston.

The first, wider photo is just using the camera on it's own ... it has trouble auto-focusing when you are close-up ... but sometimes you can fluke a good one. Not quite here.

The others came out mostly ok.

Paul.

This is may favourite period of Mcgee's work. So moving.

Plenty of Chardonnay and the right marketing and you could enjoy the same success (self satisfied poverty) the rest of we artists do.

:P

Interesting post.

Paul, It's hard to be sure (since I stopped looking down a microscope every day, I think my own eyesight has gotten worse!), but it looks to me like the teeth in the first post are filed with a bevel or fleam, or whatever we agree to call it, and are therefore nominally 'crosscut'. In the second post, they look more straight across, though there seems to be some slight variation, and a bit of bevel, which is almost inevitable no matter how careful you think you are being. Rake angles are really hard to estimate by eye, but 25 degrees is getting up there for general purpose work. I find somewhere around 15-20 max is more suitable on small back saws (crosscut) and 5-8 for rip pattern, but there seems to be a fairly wide range of what folks like, so you need to experiment to determine what suits you best.

I can see some pretty severe 'cows & calves' in a couple of pics - someone needs a bit more practice to get those file strokes dead even on each pass....

Cheers,

Originally Posted by IanW

I can see some pretty severe 'cows & calves' in a couple of pics - someone needs a bit more practice to get those file strokes dead even on each pass....
Cheers,

I didn't take into account in writing up that I had had the advantage of seeing the teeth first-hand through the loupe, which makes for better vision and full flexibility in moving things around into the best angle ... so the photos are a bit of a poor attempt ... but see below!

Just a reminder - the first photos were from a S&J Mermaid that came to me from England (10tpi), and the second a Disston Keystone K1 that I bought from AndrewR which had been professionally sharpened (11tpi). [I've only now worked out the tpi. My God ... 18 or 20 tpi must be miniscule.]

Re the rake, the teeth of the S&J look like a row of vertically positioned equilateral triangles. I reasoned out the rake from that ... I haven't measured anything. The teeth of the K1 are just slightly more forward tilted than the S&J, and again I was guessing estimating angles.

It is more and more interesting to look at these teeth. There are saw doctor's around, where are the saw dentists?

I don't know when the S&J would have been last sharpened, and it is a bit like archaeology to look along the toothline ... the filing is quite inconsistent along its length. The cows and calves you mention are mainly present for about 2 inches at the toe and two inches in the middle, but you can see variation in sections all the way down. I'm guessing it has just been touched up here and there with its last owner.

The K1 is very consistent all the way along, but I saw something interesting there too that seems to concur with something that I read recently - maybe from Bob S. It is 14" long so about 154 teeth. I'd say about 40 of the teeth had partial flats on the top - which look to me to be from the initial jointing rather than from wear as it was bright metal and had plough lines visible running down the direction of the saw blade. Maybe I'm wrong, but the article had said that you needn't try obsessively to remove *all* the flats from jointing - that it was more important to keep from shortening some of the teeth and it can sort itself out over successive sharpenings.
That would seem to me to be the story with these teeth.

Also the gullets of the K1 are very consistently flat across. The S&J has the gullets sloping a small amount to each side. Maybe this is a natural result of hand-filing and not obsessively keeping the file level. I have only sharpened a 3/4 tpi saw and a very ordinary pruning saw (wow what a difference), and I noticed that unless I concentrated I was definitely tending to have the handle a bit lower than the tip ... maybe to do with seating position and the height of the teeth and the vice. Or being slack. And ignorant

Technology ... I'll start another post.

Paul.

First I meant to give an example of the photos not always being an excellent representation. Here are two pics of the S&J that would persuade you that some of the teeth are 'worn to buggery' [technical jargon - sorry]. But actually none of the teeth really look this - they are all quite pointed.
It is just incompetent photography.

I said that I had initially thought of the USB microscopes, and of course had Brent Beach in the back of my mind. Jaycar I knew had a/some USB micros ... looking it up there is one for $99. Looking at some of the other Google links, there was the same thing from China or Hong Kong for about $59. A bit more searching turned up the same thing (basically) for ... $19!

There is (of course) some great info out there re these things ... and I already knew I only wanted about x20 magnification.
There are a couple example pics off the net attached.

Jaycar site:
USB Digital Microscope - Jaycar Electronics

Video on Jaycar site:
[ame=http://www.youtube.com/watch?v=mOOEGF7qvB4]Digital USB Microscope - YouTube[/ame]

Ebay examples:
eBay Australia: Buy new & used fashion, electronics & home d
eBay Australia: Buy new & used fashion, electronics & home d


Then I came across this excellent information for born fiddlers: How to use a Webcam for a microscope:

This is short but only the first 30 seconds is worth watching:
[ame=http://www.youtube.com/watch?v=IsDpTfDD7-s]Turn any webcam into a powerful magnifier(microscope) - YouTube[/ame]

This is an excellent little demo/presentation:
[ame=http://www.youtube.com/watch?v=RyQmVHcAMsI]Turn a Webcam into a Microscope - YouTube[/ame]


Finally I realised that there were links for lenses to attach to smartphones to do the same thing!

Iphone ...
[ame=http://www.youtube.com/watch?v=YokWp_a8gHc]video of 60 x zoom Microscope for iPhone 4 with White 2-LED and Note Detector LED from Trait-Tech - YouTube[/ame]

This one is longer, but kinda fun.
[ame=http://www.youtube.com/watch?v=oPV9lD9Fw04]The BEST iPhone Camera Lenses! Plus: Nook Tablet, Tekzilla on Google+ and Why is My PC So Slow? - YouTube[/ame]

So my cheap micro has been ordered

Cheers,
Paul.

Originally Posted by pmcgee

My God ... 18 or 20 tpi must be miniscule.

You're not wrong! Well, 18 is not so bad, I feel pretty comfortable with that pitch, now, but it goes downhill rapidly after that. I have cut a set of 25 tpi, on a very small saw, and it took all the concentration I could muster. At that size, a single light stroke of the file virtually cuts a full tooth. I don't think I would like using the single lens loupe like yours - I need both eyes to triangulate on those points!

Originally Posted by pmcgee

....
... the filing is quite inconsistent along its length. The cows and calves you mention are mainly present for about 2 inches at the toe and two inches in the middle, but you can see variation in sections all the way down. I'm guessing it has just been touched up here and there with its last owner....

If the pattern is regular, it may have been sharpened on a machine that was set slightly off the correct pitch, giving a 'vernier' effect. If there is no pattern, & if smaller teeth are all over the place, then poor filing is the likely explanation. It's pretty easy to do a job like that. I know, I did lots when I first started....

Originally Posted by pmcgee

.....The S&J has the gullets sloping a small amount to each side. Maybe this is a natural result of hand-filing and not obsessively keeping the file level. I have only sharpened a 3/4 tpi saw and a very ordinary pruning saw (wow what a difference), and I noticed that unless I concentrated I was definitely tending to have the handle a bit lower than the tip ... maybe to do with seating position and the height of the teeth and the vice. Or being slack. And ignorant

I wouldn't beat myself up about a bit of slope creeping in, I think the main criterion is consistency. A bit of slope on crossscuts is neither here nor there, and may even be desirable (refer to the discussion on that topic), but I confess that when I introduce any significant amount of slope, I double the difficulty for myself in being consistent, particularly as you need to reverse the file angle when doing the opposite side. I draw lines at the most common bevel angle across the tops of my saw vises every few cm, which help me to maintain a constant bevel angle - haven't figured out an equivalent simple guide for slope, and in any case, I'm not trying for 'real' slope until I get good at saw filing (in another 50 years or so... ).

I would recommend finding a filing position that suits you, and concentrate on keeping the file angles the same, all the way along the saw. I find I can't sit down to do this job because I need to keep my body parts at the same point relative to the tooth being filed, so I have to move along with the file.

I don't fuss about a small slope on crosscuts, but do try to keep the file dead level when doing a rip pattern, because received wisdom is that chisel points are best for this job. However, that said, I think Ch!ppy actually likes a bit of a point on his ripsaws, and my own not terribly exhaustive tests showed that with backsaws of 12 tpi or finer, crosscut or rip pattern cut at pretty much the same rate in both ripping & crosscutting modes in softer woods of about drawer-side proportions. The most easily noticable difference I could find after comparing several pairs of saws of the same tooth pitch was that the rip pattern gave a slightly more ragged cut on the exit side, compared with its equivalent crosscut partner.

Small-toothed saws will cut fairly well even when the sharpening job isn't terribly good (I can vouch for that - used them like that for years! ). If it wants to wander left or right, a bit of light stoning can make them run true enough for most purposes. The main difference between a tolerable and an excellent job is the smoothness of the cutting action, and the quality of the cut surface. I think it takes agreat deal of practice to get really good at saw sharpening - been at it a while myself, and still have a goodly ways to go....

Cheers,

hard to tell from the pics, but i'm curious, how long are those saws? they appear to be longer than 12", maybe 14"?

their definitely CC saws imo, just with not much bevel/fleam angle, more than likely with a couple of reasons in mind (or mistake)..general purpose, to rip and crosscut a tenon etc, and to try and provide a reasonably smooth cut, everything is a tradeoff

Here are two pics of the S&J that would persuade you that some of the teeth are 'worn to buggery' [technical jargon - sorry]

actually the long recognised technical term used on site, or not in mixed company, goes something like 'that saws as blunt as my d***'

I've only now worked out the tpi. My God ... 18 or 20 tpi must be miniscule

they are small, do get hard to see when your eyes get older..those amount of tpi are better for finer work in timber, say 10mm thick or for making those nice decorative boxes for example, for 20-25mm thickness then 15-16 is generally as fine as you need go, even in thinner timber 16 tpi can be fine

Maybe I'm wrong, but the article had said that you needn't try obsessively to remove *all* the flats from jointing - that it was more important to keep from shortening some of the teeth and it can sort itself out over successive sharpenings.
That would seem to me to be the story with these teeth.

true, up to a point..maybe its a bit like saying its better to cut that length of timber too long than too short...once the teeth are too short then they arnt cutting much and not at all at the point of the tooth, if a few still have flat tops then in subsequent sharpenings they will come back (the teeth grow back ,lauging at my own jokes apparently small things amuse me) if your saw has just a few teeth missing then instead of filing away some valuable saw plate you can get away with just using it and over the months or a year or so, depending on how much you use the saw they grow back. however, conversely if you havnt got the tooth point, filed to the point, as it looks in that pic, over much of the saw then its not working as it should either (that pic is showing at least a half an inch of teeth in a row, not one tooth here or there which is too much imo), particularly in the case of those saws which have not much bevel/fleam angle, they rely also on the tooth tip to cut, its already slow going (cutting, with the very slack rake angle) which is the trade off for a smoother cut/less tearout but with the chisel point/top of the tooth flat it cant do its work well, yuk lol.

one reason, a shallow bevel/fleam angle is used is less about the bevel angle of the tooth but more about the angle of the tooth tip when viewed from the front of the saw/tooth, bevel angle should prob take priority though (what i call the skew angle of the tooth- but thats just my terminology as i often describe the tooth (especially in regards to rip teeth) in terms we use for chisels-makes it easy to understand to others ime, e.g if you have a rip tooth then the tip is described as having a square chisel tooth (it cuts the same as a chisel we all understand), if you file the back of a rip tooth without changing the shape when viewed from the side, by dipping the file handle introducing slope and forming sloped gullets, it changes the tip shape of the tooth to have an angle instead of a square top, which looks like a skew chisel, anyway thats just me, i think the correct term is point slope of the tooth or something like that). with a CC saw you might want to change the skew angle (point slope) to make a cut more suited for hardwood, part ripping duty, durability or sometimes smoothness of cut depending on the timber, so you file with less bevel/fleam angle...seems lately we keep coming back to this (and i am not tring to press the issue) but the other way of achieving a different skew angle/tooth tip point slope, without having to sacrifice desired bevel angle is to introduce slope when filing

25-30 deg rake you think; it can be hard to tell, easy to get wrong on a saw that had some use and if the file you put in the gullet has a different rounded point to the triangle edge that sits in the saw, it can rock around a fraction, misleading you a bit..otherwise some ppl do happen to file them that way, i think they just assume the top of the file (the flat edge thats not doing any cutting) should be horizontal, others simply make an error, its pretty easy to move the small file a fraction the wrong way when filing and end up with too much rake, easier to stuff up than fleam/bevel angle i think. the slack rake angle can be a real dog of a saw to use, to the touch they can feel sharp but you just dont seem to get anywhere when you saw, but they do have their uses, they can reduce tearout so if your cutting mouldings ect in a mitre box it can help, can help with some joinery in making windows too, probably a dozen other places too that i cant think off atm, (might be wrong but those saws look like sash saws to me too btw, akas carcass saws nowadays i think), anyway i can live with a saw used in mitre box for mouldings and such with slack rake angle but for most everything else i want something that gets on with the job and cuts quicker...from what little i can see the disston looks like a saw for duel purpose, the other looks like, at best made for general purpose otherwise is just a mistake and has over time come to be filed that way..like chinese whispers change the original message

cheers
chippy

First - I forgot to say - the loupe is brilliant for those tiny little splinters that you can feel but not see. I thought to look at one that was bugging me and it looked like a fence-post in a zen garden

Second ... thanks Chippy (and Ian)! I've made quite a few test cuts in the past week or so, and most of the time I can start purely in the forward direction ... although sometimes it meant dropping the saw nearly parallel to the ground to get started ... not sure if that sounds like the 'right' approach.

I even used the 'unusable' saw on some jarrah and it was alright ... but with the thin blade it's pretty easy to steer it offline. At the moment I prefer the thicker blades ... or maybe the thin blade might have too much set?

Lastly - I took a survey of my backsaws - a poor neglected collection of 20 sitting and waiting for someone with a clue to come along and save them. All are as they arrived at my front door. [Last three pics below]

If I could refer to the row of upright equilateral triangles pattern as the 'rest' position for sawteeth, then almost all of the saws were more forward-leaning than that. One was raked further backwards than that - basically making it cut on the pull stroke. It was a Tyzack and I'm sure he would have rolled over at least once in his grave at the thought.

Looking at the S&J - with its teeth in the rest position - after looking at the others made it now seem very unusual. Two others were filed the same - two Slack&Sellers that came from the same seller.

I made rip (tenon-style) cuts with all the saws that could cut at all, narrowed it down to the best handful, cut with them again and then examined the best cutting two - a 9" Alex Mathieson and a 15" Groves and Son. It was interesting to see the different kerfs they all cut.

Also I made crosscuts with the two best as well as Andrew's K1, the S&J, and one other saw.

The three 'rest position' saws cut reasonably in the rip cut, but bogged down and went nowhere crosscutting after a few mm.

The K1 cut well both rip- and cross-cut ... it's disadvantage was only that it is a little light compared to the brass-backed saws. It is 14" and weighs about the same as the 9" Mathieson ... and the 15" Groves is much heavier.

The 9" and the 15" were very interesting. They are not 'officially' sharp, and the teeth on both are all over the place. The 15" is in fact concave along the toothline by about 2mm. But ... they both cut back and forth like little chainsaws - smooth and effective on every stroke and a pleasure to use. That gives me a standard to measure against when I try to not wreck one of the others with a file

I took pics of some teeth from both of them - and naturally they are forward of the 'rest position'.

One other was also interesting in that it was like a chainsaw also ... as in texas chainsaw massacre. The set on it was ridiculous compared to the others ... I think you will tell which kerfs it made.

Measuring the teeth I got 1.5mm = 61 thou. The blade is 30 thou. (It is a 16" John Cockerill) The teeth on this saw are also in the 'rest position' ... but spaced out. I took on photo trying to show the set - which looks huge by eye/loupe - but it doesn't show as well taking photos like this. I've also taken a pic of the teeth on this thing.
In making the rip cut, the wide kerf was a disadvantage - like a pool cue in a retic pipe - but it worked ok in the crosscut. I'll try it with four sheets of paper in a vice and see if I can pull the set back.

The final two pics are the final five saws and their five crosscuts in the same order. The S&J was #2 from the left and had basically stopped cutting. The 9" was willing but suffered from the short blade and the inconsistent teeth.
The Groves did better than the K1 with the extra weight and surprisingly fine kerf. And lastly of course the chainsaw.

Cheers,
Paul.

BTW - Jarrah? or Karri?

BTW - Jarrah? or Karri?

hard to be 100% certain looking at a screen but def looks like Karri given the choice of the two, jarrah tends to darken with age too, at least somewhat darker then when first cut/milled/new, to a deep mahogany colour, which is what is was first commonly called in the old days. they are both eucalypt's but if i remember karri last specie name goes something like varicolour or diversicolour or something like that, which i always thought meant it described the difference in its heartwood and sapwood colour and that it can vary a fair bit (different samples) from light pinks to sometimes golden hues(at least thats how i remember it), even though it can often look very similar to jarrah too, especially when new ...try burning a few splinters, seeing how your cutting bits off lol, jarrah should have a black char whereas karri will leave a white ash

cheers
chippy

check out the horns on some of those saws, they do the R.M Williams logo proud, you could hang em across the back window of ya Ute

Re the John Cockerill saw with wide set ...

I wanted to try the method The Schwarz showed once with the saw in a vice with paper wrapped over the sawteeth.

I've got an idea he only used 1 sheet width per side - could be wrong - but I used two. I think I heard a sheet of paper estimated at about 4 thou - again - could be wrong.

Highly sophisticated approach ... as usual ... I used my saw vice ... well ... ok the piece of pine I used to sharpen the only two saws I have ever touched with a file.

It did work. The teeth left an impression in the paper, and the kerf is reduced.
I don't know if it would adversely affect the performance of an already sharpened saw - changing the tooth geometry?

This saw definitely cut -slower- after the squeeze. Maybe I will try to sharpen it and see what then.

Cheers,
Paul.

(the 'net has been wierd today )

Saw in the 'vice'
http://i1250.photobucket.com/albums/...5-05130552.jpg
http://i1250.photobucket.com/albums/...5-05130616.jpg


The impression of the sawteeth - if you can make it out:
http://i1250.photobucket.com/albums/...5-05130701.jpg

End result - left two kerfs:
http://i1250.photobucket.com/albums/...5-05131052.jpg