Waterjet cutting

Discussion in 'Saw Makers Forum' started by fred0325, Apr 23, 2013.

  1. fred0325

    fred0325 Most Valued Member

    Messages:
    1,084
    Hello all,

    I should perhaps stay away from technical matters but I saw an example of waterjet cutting just recently and when I got the chance to talk to the person who had it done, I thought that it may be applicable to cutting teeth on saw blades, or indeed, the blades themselves.

    There are two types of cutting as far as I can see, pure water and water plus an abrasive, usually garnet grit. The water + abrasive has a cutting tolerance of about 0.8mm and which is not sufficiently tight for saw teeth, but with water only I think that you can get down to 0.2mm and which is a lot better in terms of accuracy.

    It produces no heat and purportedly does not distort the plate. (Therefore no need for secondary "smithing" or "tensioning"). It also cuts reasonably accurately up to 50mm of steel and multiple items can be cut at the same time to reduce cost, a consideration if you are producing new saws.

    I thought of it, not in terms of new saws but in converting the plethora of old rip saws into usable crosscuts. You could both joint and re-cut the saw using this technique. I suspect after seeing some of the intricate work done on various internet sites that it may be possible to put the fleam on as well as the rake, to the same accuracy so that filing, if any is needed is kept to a minimum.

    I am also told, however that this technique is best on a "blank canvas" and is not so good at working with existing shapes, so that amending teeth numbers or shapes would not be possible.

    Is there anyone out there already doing this? Or anyone who knows the cost which I suspect may be prohibitively expensive.

    Or just anyone with any ideas on it.

    Fred
     
  2. lui

    lui Most Valued Member

    Messages:
    77
    Hi Fred,

    It's been a while, I never have enough time to post, but I do stop by on a regular basis.

    The Water cutting is something that I've been asked to look at, by a couple of people. I've been asked about 2 man cros cut saws, large pit saws and japanese pull saws, I'm not geared up for any of these and have stated to look into water cutting. I don't have prices yet, and your idea of stacking blades is very interesting.

    If anything comes of it I'll let you know.

    regards

    lui
     
  3. TraditionalToolworks

    TraditionalToolworks Most Valued Member

    Messages:
    181
    I've heard the teeth of the plates on Adria saws are water cut.

    Rumor has it Eddie has it done in Japan.
     
  4. Kermit

    Kermit New Member

    Messages:
    1
    Some answers

    I am thinking about it. Indeed I am preparing designs.

    A few issues I do know the answer to. Stacking is a no go. The stream spurts sideways between layers and erodes the sheet faces. There is little heat generated and the water cools everything very quickly, it is the best way to cut hardened steel. Rip filing can be achieved on any machine but few can do angled cuts so no cc. Oh, and the process leaves one hell of a burr on the Bottom side.

    Cutting at techshop runs $2 a min for pump run time but the cuts are fast so the final price should be reasonable. Not sure what you might pay to have someone do it for you.

    If you are near a techshop or other member workshop you might check if they have a water jet and get their take on capabilities. I do not plan to use it for small saws so I was not concerned about resolution (your accuracy) but I think it is less of a problem than you seem to feel it is. Indexing is an issue. I will be working from sheet stock and cutting the whole saw in one go. Recutting an existing saw would be a scary to do accurately. On the whole, I think jets are best suited to doing large saws not backsaws.




    Disclaimer: I am a techshop member-instructor. Not shilling for them here just happen to know the run costs they charge.
     
  5. Force10Matt

    Force10Matt Member

    Messages:
    17
    I've just had my first batch of fresh blades made. I can confirm waterjet is 100% the way forward.

    I'm lucky in that one of my customers runs a waterjet and is happy to swap time on the waterjet for having various cnc tooling sharpened but even if i were paying full price for it it would still be well worth it. They bill it out at £250/h but cutting 5m of 14ppi toothline and 3m of 12ppi toothline onto sheets of .5mm and .6mm stock took about 20 mins.

    The resolution isn't really good enough for the 14ppi but it stil gives a perfect spacing and with two passes of a file the toothline is immaculate. with the 12ppi toothline the larger teeth are more forgiving and the resolution of the cut isn't too much of a problem, one pass of a file is all that's required to make them right. I'm going to experiment with various other tooth patterns and with having other plates cut. in particular having breasted variable pitch toothlines replicated for restoring old saws but that's a way off yet, for now i'm just glad to be able to bring saws with worn out or badly damaged plates back to life.

    The cut itsself is near perfect, there is no burr whatsoever, the abrasive does not mark the surface of the sheet at all, it would if sheets were stacked though as Kermit pointed out. The biggest problem i've got is preventing the sheets rusting, you know how saw plate is, it'll rust as soon as it has a chance, just in the time it took the chap running the machine to stack one sheet and cut the other it had already started to develop a few spots, luckily i was there and wiped them down with oil but i could see it being a problem if they were left for more than a few minutes.

    I'll attach some pictures of the cutting process, the result and a saw i fitted a plate to yesterday. I think it's come out rather nicely.

    Cheers

    Matt
    waterjetsaw1.jpg waterjetsaw2.jpg waterjetsaw3.jpg waterjetsaw4.jpg
     
    ray and shoarthing like this.