Author Topic: A very interesting video!  (Read 1571 times)

Offline mattinker

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A very interesting video!
« on: July 11, 2017, 12:58:59 AM »
All of the Clickspring videos are interesting! I thought of you Steve (VTsteam) when I saw this!



<a href="http://www.youtube.com/watch?v=SOw9WqMOHjA" target="_blank">http://www.youtube.com/watch?v=SOw9WqMOHjA</a>

Offline chipenter

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Re: A very interesting video!
« Reply #1 on: July 11, 2017, 01:47:20 AM »
My great granfather was a file cutter , he had some strange hammers shaped like a pear , and a curved handle angled down about 45 degrees , weiging up to 4 pounds , acording to my dad he cut the teeth sideways with a twist of the wrist and very quickly . 
Jeff

Offline PekkaNF

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Re: A very interesting video!
« Reply #2 on: July 11, 2017, 01:53:22 AM »
Thnak you, that is interesting!

My browser at the work does not support embedded videos.

Clickspring
Antikythera Fragment #3 - Ancient Tool Technology - Hand Cut Precision Files

https://youtu.be/SOw9WqMOHjA

Pekka

Offline SwarfnStuff

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Re: A very interesting video!
« Reply #3 on: July 11, 2017, 02:40:52 AM »
Yep, I've been subscribed to his videos for quite a while. Well worth a look down his list as he makes many items of tooling as he needs them.

John B
Converting good metal into swarf sometimes ending up with something useful. ;-)

Offline Biggles

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Re: A very interesting video!
« Reply #4 on: July 11, 2017, 11:37:39 AM »
Iíve been following the series of the Antikythera and the making of rounded knurled edges. I find him very interesting and easy to follow.

Offline vtsteam

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Re: A very interesting video!
« Reply #5 on: July 11, 2017, 10:21:05 PM »
All of the Clickspring videos are interesting! I thought of you Steve (VTsteam) when I saw this!

Absolutely fascinating! Loved it Matt. Thank you!  :clap: :beer:
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline vtsteam

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Re: A very interesting video!
« Reply #6 on: July 11, 2017, 10:41:58 PM »
It's funny because I had found myself thinking about case hardening again, last week after re-reading the attempt at a mod-up I did a couple years ago. So I watched the Clickspring video tonight about that case hardening, too. Lots of new and useful information, and he does a really superb job of neatly working on camera, and filming and editing. First class job!

I do find I have some questions about the method for making the files, and perhaps I will try it myself when I can, just to find out the difference.

His method is to cut the files first then case harden them, and finally temper.

I was thinking of case hardening and then annealing, then cutting teeth and hardening followed by tempering.

The tricky point is the heat and exposure to oxygen after cutting the teeth in either procedure. Because that degrades the tooth sharpness. His method would at first seem better that way, as the hardening stage is in an oxygen poor casing of his pack mix. But I noticed he cracks it off in the presence of air. I saw a fair amount of scale (oxidation) as the pack was removed, and during the slow plunge. It also seemed to take a long time to plunge.

I was wondering if the heating to harden in my second proposed method could be done in a slightly reducing atmosphere, and then a quick plunge into water, reducing oxidation and better preserving the teeth? I don't know how well the tooth making would go in annealed case, either. But something to try some day.

I guess the proof is in the pudding. Wish I didn't have so much I have to do at present -- including finishing the lathe.
I love it when a Plan B comes together!
Steve
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Offline S. Heslop

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Re: A very interesting video!
« Reply #7 on: July 13, 2017, 07:13:20 AM »
That method for case hardening looks useful. I tried a while back to case harden in a sealed steel box filled with charcoal powder, and it burst open and flung the contents out. They were thankfully only a little warm but it was enough to make me nervous about trying it again. I figure the clay is permiable enough to prevent that from happening, but it'd still be a little scary.

I was thinking of case hardening and then annealing, then cutting teeth and hardening followed by tempering.

The tricky point is the heat and exposure to oxygen after cutting the teeth in either procedure. Because that degrades the tooth sharpness. His method would at first seem better that way, as the hardening stage is in an oxygen poor casing of his pack mix. But I noticed he cracks it off in the presence of air. I saw a fair amount of scale (oxidation) as the pack was removed, and during the slow plunge. It also seemed to take a long time to plunge.

I saw that commercially they heat files for hardening in a molten salt bath to reduce oxidation. Seems like an awfully dangerous thing to mess about with though. Also even then the teeth dont come out perfect, so they give them a quick sand blast to clean the teeth up and sharpen them. An acid bath might work too, I think i've heard of that being used to sharpen worn files.

When I made those rasps I was using as reducing an environment as possible, and also rubbing the the thing with regular bar soap. The soap didn't really stick to the rasp once it got hot, but it seemed that it did help. They came out not too far from how his files did after case hardening though, along with some light cracking.

Offline mattinker

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Re: A very interesting video!
« Reply #8 on: July 13, 2017, 08:16:18 AM »


I saw that commercially they heat files for hardening in a molten salt bath to reduce oxidation. Seems like an awfully dangerous thing to mess about with though. Also even then the teeth dont come out perfect, so they give them a quick sand blast to clean the teeth up and sharpen them. An acid bath might work too, I think i've heard of that being used to sharpen worn files.

Letting files rust is a way of sharpening them, it works well!

Offline seadog

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Re: A very interesting video!
« Reply #9 on: July 13, 2017, 08:48:42 AM »
In the same way that reapers used to leave their scythes out to weather. A quick wipe with the whet stone come harvest time and they were razor sharp.

Offline awemawson

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Re: A very interesting video!
« Reply #10 on: July 13, 2017, 10:05:15 AM »
I suspect that was more that it formed a bit of a saw edge rather than the dead straight one a conventional sharpen would give.

I have two pairs of sheep shears, both pretty sharp, but one works dramatically better than the other as the edges are micro serrated. I suppose that it stops the wool sliding along the blade quite so easily. Perhaps I should try rusting the other set !
Andrew Mawson
East Sussex

Offline mattinker

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Re: A very interesting video!
« Reply #11 on: July 13, 2017, 11:12:34 AM »
In the same way that reapers used to leave their scythes out to weather. A quick wipe with the whet stone come harvest time and they were razor sharp.

I discovered that here in France, there were small anvils for sharpening sickles and scythes.

Offline mattinker

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Re: A very interesting video!
« Reply #12 on: July 13, 2017, 06:25:39 PM »
I suspect that was more that it formed a bit of a saw edge rather than the dead straight one a conventional sharpen would give.

I have two pairs of sheep shears, both pretty sharp, but one works dramatically better than the other as the edges are micro serrated. I suppose that it stops the wool sliding along the blade quite so easily. Perhaps I should try rusting the other set !

How about sharpening with very coarse stone?

Offline Chilliphil

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Re: A very interesting video!
« Reply #13 on: July 14, 2017, 07:46:31 AM »
Part of the process of sharpening a scythe is known as peening - the term relates no doubt to ball pein hammer etc. It's quite an art as you might expect. https://scythecymru.co.uk/scythes-for-sale/peening/

Offline vtsteam

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Re: A very interesting video!
« Reply #14 on: July 14, 2017, 09:18:24 AM »
The difference between sharpening and fining an edge. Like the usage variations slicing, sawing and scraping, all needing different kinds of edges.
I love it when a Plan B comes together!
Steve
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Offline mattinker

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Re: A very interesting video!
« Reply #15 on: July 14, 2017, 09:59:35 AM »
Part of the process of sharpening a scythe is known as peening - the term relates no doubt to ball pein hammer etc. It's quite an art as you might expect. https://scythecymru.co.uk/scythes-for-sale/peening/

Peening has several uses, apart from drawing out and straightening blades, it is also used on welds to relieve stresses and to straighten bent bars. Peening can be done with a hammer or a needle gun. The pein refers to the "other" side of a hammer eg cross pein straight pein are peins, as much as ball peins!

Offline stvy

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Re: A very interesting video!
« Reply #16 on: July 26, 2017, 04:19:03 AM »
Ref Peening -- I straightened up my sagging bridgeport mill table with peening. I am told that the reason for the sag at the table ends is due to:

1. Heavy objects being placed there (and the lack of support for the table ends on the knee in the design)
2. Stressing of the table by over tightening of e.g. the vice to the table in the tables center. The t-slots get stretched.

I had 0.004" of sag in my table. To encourage the table to straighten back up from the effects of 2, the procedure was:

1. Rough scrape of the table top.
2. Wringing the table by suspending it and hitting with a hammer. (Apparently to get stresses out, step 1 is needed to make that work as well as it might.)
3. Peening the underside in the mid section

The results of this was that within 5 minutes of work the sag was reduced to ~0.0015".

I then proceeded to scrape the table as normal. The benefit being that I had to scrape away far far less material.

If your attending the Richard King course ask him about it. It works.

Steve

Offline PekkaNF

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Re: A very interesting video!
« Reply #17 on: July 26, 2017, 03:32:40 PM »
On one mill about 30 years ago one old maintenance mechanic told that they did exactly the same thing with Miller milling machine table. After peining and straighteneing it kept on bending and did not stabilize. Can't remember exact numbers, but ennough for conversation.

Pekka