Does that mean we will have to translate for the next two weeks and you won't be covering the forthcoming budget? Actually that could mean she will have more time time to devote to your posts if her contract with Fairfax is on hold!
Regards
Paul
Printable View
Matt
That should read what was next? I have just packaged up this afternoon these two. A Disston No.12 (12ppi)
Attachment 411668Attachment 411669Attachment 411670
It's a lotta teeth I can tell you on a 26" saw, but a beautiful handle.
and Simonds No.371 (9ppi)
Attachment 411671Attachment 411672Attachment 411673
:)
Regards
Paul
So what is next?
Well, no more saws for the moment, at least not as far as restoration is concerned, but the 18" Kenyon styled saw at the beginning of this thread I am going to use as a test bed for a hammering test. I have been following Rob Streeper's thread on saw hardening and plan to subject the "Kenyon" saw to a right old hammering.
I don't have the equipment for hardness testing, but I think that this technique may serve to stiffen the saw plate. I propose to hang the plate over the end of the bench, attach a weight and then measure the deflection. Then I will hammer the saw in the manner determined by Rob and measure the deflection again. What do you folks think will be the outcome? (Yeah, yeah, I appreciate that the plate will bend).
Regards
Paul
I haven't read all of Robs Streeper stuff and I'm tired and it's late well for me anyway.
But if you are going to hammer the plate to harden it.
You will also make it more brittle not a good thing.
In a saw especially.
Or are we just hammering the plate to bring some stiffness to it.
Confused Matt
Yes Matt.
Hammering for stiffness. I think that brings some hardness with it. My limited understanding of such things is that in expanding the molecules some degradation occurs as well as stiffening and hardening. I think there has to be a balance there somewhere. I'm hoping Rob will step in here, but I know he is snowed under (is that possible in Texas?) with a work project.
If the object were just to make the plates harder I think that could have been accomplished by the early manufacturers by heat treating. My conjecture therefore is that it is to introduce stiffness to the plate. Of course I could be up the wrong tree here.
Regards
Paul
I think that by 'tensioning' the ancients really meant 'adjusting the tension'. I haven't been able to detect any change in static sag - I think I posted on this subthread somewhere about it.
Grains, which are crystalline in nature, not molecules. The various atoms that make up solid metals and metal alloys arrange themselves on cooling from the liquid state into regular ordered structures known as grains. There are no covalent bonds of the types that make up organic molecules present in metals. The molecules Matt refers to are less suitable I think.
In the process of cold mechanical working of the metal the grains are distorted which changes the bulk properties of the metal. I've found that cold working 1095 steel tends to increase the measured hardness by about 4%, even in areas that are adjacent to those that are struck. This strain hardening was first reported by Bauschinger in the latter part of the 19th century. https://en.wikipedia.org/wiki/Bauschinger_effect
You may recall a while back that I'd done an experiment with heat treating a 1095 saw blade that had been cold-worked. I took some measurements the other day and the increased hardness remains but the standard deviation of the hardness is very low. I need to do some comparative measurements yet but I think I've re-discovered how to do another of Disston's 13 points.
Paul,
Great saw. I love the Tulip Oak handle. I've only ever seen that wood one other time, and it, oddly enough, was also a saw handle which had been made by IanW. I missed this original thread I believe. The panel saw is also great.
Looking forward to the next one!
Cheers,
Luke
Paul,
If you're interested in an excellent superficial hardness tester I can recommend this: Portable Ames Model 2S Precision Hardness Tester Rockwell w/ Accessories | eBay
$800 is a good deal relative to the regular price. Just the ticket for quantitative analysis of your hammer tensioning results. Maybe you could make an offer?:dev:
:oo: What are you saying? :D
Regards
Paul