Saw making advice needed

Discussion in 'Saw Makers Forum' started by Matthew, Nov 18, 2020.

  1. Matthew

    Matthew New Member

    Messages:
    1
    Hello,

    I have bought a few things to make a few saws. I have a retoother with bars up to 16ppi, I have some. 020 spring steel. 6 inch by 25 inches. Plenty of of old/recycled saw screws from old saws.

    But I need to buy or make some backs. I do not have a mill but I do have a drill press. I cannot access the link where someone used a drill press to slot backs. Did that work?

    I searched and found that Blackburn Tools sells backs. I reached out and I will see what he says. TGIAG and Florip Toolworks sell backs but not currently.



    What should I look for in a saw back? Thickness? Height? Slot depth? And are these pressed on at all? Or do I need a .020 slot for a .020 blade and glue it?

    Personally I'm ok with either folded or slotted. But I know I cannot get any from TGIAG or Florip Toolworks at the moment.



    Matthew
     
    Last edited: Nov 18, 2020
  2. Dusty Shed Dweller

    Dusty Shed Dweller Most Valued Member

    Messages:
    120
    Matthew, you're starting to paddle in murky waters here and risk opening up the old "slotted" versus "folded" backs argument. Those doing it will certainly not give you the 'how to' as this IP is typically closely guarded proprietary information.

    I'll state my bias up front, I'm very much in the folded backs camp.

    The bottom line..... Folding backs is very difficult to do well, and we don't know how the old Sheffield companies managed to do it so effectively. It's not as simple as squishing bar in a press. The benefit of folded backs is repairability - the ability to re-tension the plate as it can move relative to the back if there is a problem such as a catch etc. Folding requires tooling that costs thousands of dollars and a big press, plus knowledge of working brass. It's not a backyard operation.

    The slotted back school is a purely modern development. Basically you mill a slot into brass/steel bar and glue the plate in. Only nominal clearance is required and you don't crimp it later. Technically it's an easier operation because a competent mill operator should be able to this basic work on a standard mill, but in reality accurate slotting is difficult over significant lengths. Any wobbles will transfer directly into the plate. The main issue with a glued back is that the plate is fixed, so any issues in use will irreparably kink the plate. Another problem I have is that many of the slotted backs aren't solidenough, and any movement will mess up your dovetails.