Suggestions for making saw backs: folded, slotted or laminated?

Discussion in 'Saw Makers Forum' started by Mike Allen, May 6, 2011.

  1. Mike Allen

    Mike Allen Member

    Messages:
    5
    I am a new member to the Backsaw Net and I sincerely admire and appreciate the collective talent and knowledge of the members.

    I have been an avid user of vintage hand saws for many years. I recently made my first attempt at making some backsaws with decidedly mixed results. I will try and post some pictures below.

    I'm looking for suggestions about the best way for a home hobbyist (with minimal metalworking skills/tools) to make brass saw backs for dovetail/backsaw? I'm aware of three various techniques; folded brass backs, slotted solid brass rod and laminating the saw plate between strips of brass. Currently I only have the skill/tools for the laminated backs. I guess I could find a machine shop (hopefully?) to cut the slots in a solid brass rod, or I guess build some kind of a angle iron-based folding tool for the folded back.

    I don't have much in the way of metalworking tools, really just a electric drill and hand punch for making holes in saw plates. As a consequence, I tried laminating the saw plate between 1/8" thick strips of 260 brass alloy, drilling/punching 1/4" diameter holes through the laminate and peening 1/4"diameter brass rod in the holes to help hold the epoxy together. Three of the four I've done came out OK, however one was as wavy as 10 miles of bad road (I'm not sure if it's visible pictures below of the straight and the not so good)).

    So in summary I guess I'm not doing that great with the laminated technique and am looking for suggestions from this forum about whatever you think is the best technique for someone like me to focus on. Maybe, the recommendation will be to just stick with the laminated technique and get better at it -- I don't want to invest the time if the collective knowledge of everyone here is my effort would be better spent on another technique.

    I appreciate any recommendations/suggestions from the knowledgeable folks here.

    Thanks in advance, Mike Allen
     

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  2. ray

    ray Administrator Staff Member

    Messages:
    579
    Hi Mike,

    Welcome to the Forum.

    I used a drill press and a slitting saw to make slit short pieces.

    A rough guide to how it was set up is here..

    http://www.backsaw.net/cpg/thumbnails.php?album=20

    Click on one of the thumbnail images.

    Later, I organized a group purchase of brass, and got a friend with an engineering works to cut the 20 thou slits, it was a tricky job, and results were mixed until we got a better quality slitting saw.

    Here's the setup we used at the friends place with a horizontal mill.
    [​IMG]
    [​IMG]

    The roller infeed and outfeed guides are adjusted to keep the brass tracking correctly.

    Since those days I now have my own mill, but haven't set it up to slit any brass, since I still have some left over from the group purchase.

    I will send you a couple of pieces to have a play with, they are 900mm long, so you should get a few saws out of it.

    Pedder or Klaus might be able to add some additional comments, I think they are using a similar setup to the one described in the gallery.

    Regards
    Ray
     
  3. Mike Allen

    Mike Allen Member

    Messages:
    5
    Suggestions for making Saw Backs

    Ray,

    Thanks very much for sharing your experience and insight regarding making slotted brass saw backs. For a newcomer like me, there is no substitute for learning from someone with first-hand experience -- I really appreciate you sharing!

    After seeing the pictures of the milling machine all I can say is Wow! All that precision equipment is certainly impressive (and I have to confess intimidating to me!). I can certainly appreciate the challenge in trying to create a narrow slot in such a small piece of material given the tight tolerances.

    I'm planning to invest in a drill press so that I might be able to try using the technique you demonstrate in the photos you've attached. I will have to think about the best way to give it a shot, but I'm encouraged to keep trying.

    Thanks again, I really appreciate all the information and help!

    Mike Allen
     
  4. TraditionalToolworks

    TraditionalToolworks Most Valued Member

    Messages:
    165
    I have both a small mini-mill and a horizontal mill. Mike Wenzloff uses a mini-mill to slot the backs for his saws, but I find it to be a total piece of $#!T and despise it. I do use it for some small stuff though.

    Since using it for slotting I have setup a Nichols horizontal mill, slightly smaller than the horizontal that Ray pictured above.

    Here's my setup:

    [​IMG]
     
  5. pedder

    pedder Active Member

    Messages:
    37
    Hi Mike, great you found this forum, welcome!

    Klaus made e spine for our first saws but we found out that this is done much better on a cooled mill. As we have limited space an time, we sourced the milling out to a friend with a cooled mill in his garage (no kidding!). Since that the slots are dead straight and dead tight- We hardly need any glue.

    Cheers
    Pedder
     
  6. rstreeper

    rstreeper Member

    Messages:
    5
    Folded backs

    I press mine. After a couple of years of experiments using all of the usual approaches, i.e. hammering, forging, bar folder and so on. I think that the pressing method is the most consistent, produces backs with the fewest defects that need to be polished out, avoids the use of glue, screws or pins/rivets and also does not necessitate a horizontal mill which your average saw maker will only use for one thing - slitting backs.
    An additional advantage of pressing is that the technique is less sensitive to changes in material. For instance, slitting stainless steel can be problematic. With proper annealing it is possible to use thicker stock as well. Attached is a photo of a back I made in 304 stainless.
     

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    Last edited: Jan 1, 2014
  7. rstreeper

    rstreeper Member

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    5
    Forming Bronze

    Does anybody have any experience in the forming of bronze? The alloy I am thinking of using has, according to information on the 'net, lower machinability but superior ductility to brass, 392 or bearing bronze. I want to press some backs using 0.125" material.
     
    Last edited: Jan 1, 2014
  8. ray

    ray Administrator Staff Member

    Messages:
    579
    Hi Rob,

    I've done bronze casting, and made bits and pieces, Alan ( Traditional Tools ) has made bronze backs by slitting. I'm not sure how you will go folding bronze, I think it will depend a lot on selecting a suitable alloy, I've used Silicon Bronze, Aluminium Bronze, Phosphor Bronze, for casting, but none of those struck me as being particularily suitable for bending.

    There will be a suitable bronze alloy for folded backs, but I've no idea what it is.

    Ray
     
  9. TraditionalToolworks

    TraditionalToolworks Most Valued Member

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    165
    Wow, a couple new messages in the Saw Making Forum...a kinda surprise...I haven't been around here in a while.

    I am not clear on what you mean by "pressing", if that is folding, I have no idea how bronze will work with that. The bronze I have used is not very ductile at all, and I wouldn't expect it to fold, it is for machining.

    Would be like trying to fold alloy 360 brass, I don't think it would work and bronze is fairly expensive to experiment with.

    I once tried to machine alloy 260 brass, which is used for bending and hammering. You need a really rigid mill, IME. It is almost impossible to slot straight, although I think it could possibly be done on a horizontal with really small cuts, but it would be hard to keep straight.

    With the right setup, a horizontal mill is one of the most useful machines one could have in a home shop. Here's a pic of my Nichols with a 2" face mill in the vertical head. Yes, many horizontals have a vertical head. This machine only takes up a small amount of real estate.

    I have recently acquired a Deckel mill that is also both horizontal and vertical, similar in footprint as the Nichols.
     
    Last edited: Jan 23, 2014
  10. jakepenton

    jakepenton New Member

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    1
    I see this thread is a bit old. But if anyone is following, my question is about the possibility of welding a saw spine. I had in mind the idea of taking two mild steel pieces, and clamping a length of plate between to set the spacing. Along the top - either a third mild steel piece, or just the weld bead. MIG might be cool enough to avoid too much warping.

    Is this worth a try? I just bought a small MIG welder for other purposes. I guess I'll try it and report.
     
  11. Dusty Shed Dweller

    Dusty Shed Dweller Most Valued Member

    Messages:
    73
    It's worth a try but be prepared for it to (a) warp out of alignment on cooling and (b) be prepared for a lot of clean up filing/grinding. Straightening it would be very, very difficult. In addition, if you're using an old saw plate you don't want to put so much heat into the plate that you pull the temper.

    There are many sources in the US for both folded and slotted backs and I suggest you check those out. DIY spines are a major engineering challenge.

    People tend to be in either or two camps (folded backs vs slotted + bonding agent). Personally I don't like any type of spine that permanently locks the plate into the spine as it has the significant drawback in that it prevents tensioning of the plate to keep it straight and tracking properly.
     
  12. TraditionalToolworks

    TraditionalToolworks Most Valued Member

    Messages:
    165
    IMO, no, it's not worth trying as it will be very difficult to keep the pieces aligned as you weld them. Slotting is a much better solution. Stick with laminating if you don't have a mill.