Gallery, Projects and General > Neat Stuff
A very interesting video!
mattinker:
--- Quote from: Chilliphil 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/
--- End quote ---
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!
stvy:
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
PekkaNF:
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
Navigation
[0] Message Index
[*] Previous page
Go to full version