Page 3 of 3 FirstFirst 123
Results 21 to 29 of 29
Like Tree22Likes

Thread: Heel and toe of razor gets sharp, but not the middle.

  1. #21
    Silky Smooth
    Join Date
    Sep 2008
    Location
    Southern California
    Posts
    792
    Thanked: 154

    Default

    Think of honing a smiling blade as a knife with a slightly curved edge. Which is what such a razor actually is.
    rolodave likes this.
    de gustibus non est disputandum



  2. #22
    Senior Member
    Join Date
    Sep 2013
    Location
    NW Indiana
    Posts
    971
    Thanked: 209

    Default

    This was posted on bnb also. My diagnosis there was the same as was posted here early on in the thread - the spine is slightly crooked, so honing the blade results in one side hitting heavier at heel and toe but light in the middle and the other side hitting heavier in the middle but lighter at heel and toe. End result, the bevel has not yet been properly set in the middle of the blade on the side that hits light in the middle.

  3. #23
    Senior Member
    Join Date
    Apr 2014
    Location
    Southern MO
    Posts
    215
    Thanked: 31

    Default

    So far, nobody has mentioned the stones. I would flatten a bevel setter (1K) using the grid method to make sure it is flat then reset the bevel and watch the process with your loupe. This will confirm if it is a blade problem. If the bevel is incorrect, not set properly, the higher grit stones will not solve the issue.

  4. #24
    Senior Member rodb's Avatar
    Join Date
    Apr 2008
    Location
    Saint Paul, Minnesota, United States
    Posts
    2,624
    Thanked: 400

    Default

    Also, sometimes a 2nd layer of tape can be like magic to a problem edge. Try that after you've tried everything else and see if it helps.

  5. #25
    Senior Member
    Join Date
    Sep 2013
    Location
    NW Indiana
    Posts
    971
    Thanked: 209

    Default

    It's not the stones IMO. The pattern would almost certainly be very near the same on both sides if that were the case. Aside from this, yes the importance of stone flattening was already mentioned earlier or maybe at bnb, don't remember, and the OP mentioned he would "pencil grid and lap again," so I am pretty sure he has that down.

  6. #26
    Sharp Minded Citizen
    Join Date
    Oct 2013
    Location
    Bucharest
    Posts
    300
    Thanked: 93

    Default

    the pattern of wear described by you is consistent with a spine that is slightly bent to the side the heel and toe get sharp. Use a rueler to check if the spine is straight on both sides.

  7. #27
    Junior Member
    Join Date
    Oct 2014
    Location
    Houston
    Posts
    12
    Thanked: 1

    Default

    I think you were correct with the twisted spine diagnosis. It took some time and electrical tape, but it eventually got sharp the entire length of the blade. Thanks for the help/advice guys!
    Geezer likes this.

  8. #28
    Sharp Minded Citizen
    Join Date
    Oct 2013
    Location
    Bucharest
    Posts
    300
    Thanked: 93

    Default

    Glad it worked out....it happens because there is tension in the steel matrix...possibly due to bad heat treatment ... bad quench or insufficient tempering...
    I have seen this am many blades....when they leave the factory they are streight but in lots of years as is the case of old blades the tenssion tends to even out and bends the blade slightly....I'm sure we' all seen cracked blades that were not cracked mecanicaly...or spines rhat are not streight....the fact is many blades have geometrical defects hidden to the eye...they were made by humans not by machines...

  9. #29
    Senior Member
    Join Date
    Sep 2013
    Location
    NW Indiana
    Posts
    971
    Thanked: 209

    Default

    This is pretty common really, and isn't necessarily bad heat treatment. Often when steel is quenched it will distort if there's any residual stress. The razor makers of course need the spine to be reasonably straight, so they straighten the razors as close as possible then grind them. Over time, the steel will tend toward relaxing back to the position of lowest residual stress, so if the original bend was significant but was straightened, it can come back gradually over several years.

    One way to almost completely eliminate this issue is to perform a stress relief thermal treatment before heat treating and then do not straighten if the steel goes out of whack, but rather grind it until you get where you need to be dimensionally and straightness wise, but I don't think many would ever do this as it adds a good amount of time and therefore cost to the finished product.

    So instead they go the route that they do, and now and then you get a stinker... but you almost never know that when the razor is new so it doesn't hurt sales.
    ovidiucotiga likes this.

Page 3 of 3 FirstFirst 123

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •