Greg Sigworth

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  1. Yes there is a lot to PM, but I believe the big advantantage in cutting tools is the resulting uniform structure. I encourage anyone who can to use such steel in their tools to do so. I don't know everything there is in the metallurgy of PM; but I am a degreed metallurgist, worked ten years in the largest heat-treat facility east of the Mississippi in the automotive industry; prepared and examined over 150k micro samples of steel under a microscope for quality control, and the last two years ran the met-lab and acted as the plant metallurgist: your typical shade tree metallurgist. We had over
  2. I know this is somewhat off subject so I will keep it brief, or try to. PM steel refers to how the solid metal was formed/made. Normal solidification from a melt leaves all kinds of segregation and non-uniform structures in the steel. This effects the fine cutting edge. The blade that is formed from the steel being folded over say 20 times greatly removes this from the steel. PM steel does this from the get-go and if the other important aspects of heat-treatment etc. are observed then the results should be superior. It may take some time getting used to sharpening PM steel and it may be differ
  3. Jacob; I am sure that you will fine a replacement. I have an assortment and I could part with one if you can not find one. My e mail address is I have two working planes and a number of spares for parts that I bought for next to nothing. They are all 4 cm wide and three 10.4 cm long and the forth 9.7 cm long. Greg
  4. Sorry I couldn't help myself; must be the Covid effect.
  5. Wow I learned a lot from this post. Who would of guessed that David Burgess had Hulk Hogan working in his shop?
  6. Are you talking about the horse or about people?
  7. You should also address the cause of the crack. In dry weather, the winter the top will shrink transversely more than the ebony saddle resulting in the saddle pushing at the ends outward. This causes the top to crack at the location here. The saddle needs to be free at the ends with no glue and a space there on both sides about a business card width. Make sure this is do when finished repairing the crack.
  8. Not on violins but on other things smooth peanut butter was quite useful , peanut oil and fine peanut pulp?
  9. No experience here but I have some on old leather cases I have resurrected. Probably either the top, bottom or both is warped. Figure out which, and after the insides removed apply some light moisture/little heat , straighten and dry. The inside would look great in new plush material of a bright color. Outside? Up to you, but why not refinish after straightened. The brass fixtures as what gives this box a future.
  10. Maybe he wanted the scraper to be more stiff and put a wood back on it.
  11. Thank you for this. I just made my first shooting board and will use it to join the plates on the next violin.
  12. Worked in a lab which had this very thing. If I remember correctly the exhaust motor was special to ensure that there would not be ignition of combustible fumes. Just something that might be of concern. Oil and turpentine may not be too much of a concern but alcohol might be.
  13. When I worked in a Met Lab we made samples from gear teeth that had been surfaced hardened and tempered to around 62 HRC. We cut them with a huge 14" carborundum blade flooding it with water as we cut. Still the heat generated tempered the sample neat the cut. After mounting in thermal-plastic mounts we hand ground the surface to get below the tempered area. No more that two seconds hand grinding before putting the sample in a can of water. Repeat this at least about 15 times. It the sample tested too low in hardness then do some more hand grinding to see if the tempered area had not been rem
  14. Thank you all for sharing ideas. Question: would the arc connecting the inflection points be at the same height from the plane of the plates as one moves around the violin or would it differ? I assume the same height would be a good choice, but possibly not true in reality.