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  1. #21
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    You don't have ball screws.

  2. #22
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    Quote Originally Posted by SeaMoss View Post
    That's kinda funny. I ran a tracer a lot back in them olde dayes. I was even looking half-heartedly for a 2-30 Gorton Tracemaster, there's a lot of jobs I can do faster and easier on a tracer than by nc.

    These days, doing what everybody else does doesn't seem to be a winner, to me.
    I think I know where one is about an hour west of Houston...

    Sent from my SM-N900V using Tapatalk

  3. #23
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    Quote Originally Posted by ewlsey View Post
    You don't have ball screws.
    Yeah, I had not looked at his photos much but now see sure enough, standard Bridgeport threads there. I've only seen one of this style of Tru Trace in real life, owned by a pattern maker in NC....and his had ball screws. Which makes sense as how else can it do proper contour tracing ??

    For a few years where I manufactured dovetail jigs (for use with a router in woodworking) I used a three head Tru Trace to reproduce 1/4" plate aluminum templates for the jigs. Mine was the usual type with no screws, just hydraulic cylinders moving the axis. It was amazing how accurate it was, and once you got the stylus started on the master template you could let go of it and it would follow the template contours automatically......

    Which is amazing really considering the tight radius I was milling...since the stylus would be following the outside radius, but when it reached the 0 degree point of the radius, it would automatically start to reverse the Y axis while reversing the direction of pressure the stylus was putting on the template. To this day I don't know how it could do that, and do it so well as to produce just as smooth a finish as CNC.

    But getting back to the OP's machine....how could it trace contours with much accuracy without ball screws ? Was there a sort of backlash compensation built in ?

  4. #24
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    Quote Originally Posted by Milacron View Post
    To this day I don't know how it could do that, and do it so well as to produce just as smooth a finish as CNC.
    When I was in college I took a Mechatronics course and one of our projects was to build a small robot with wheels that could follow a path on the floor made from electrical tape. I used a single optical sensor set to detect the "grey" limit right at the edge of the tape. Set up a PID feedback system and with some tuning it actually worked very well. It was certainly capable of the kind of speed those tracers ran at.

    That was about 10 years ago. The hardware was a programmable IC called a Stamp. Total hardware cost was maybe $50.

    Now, how they did that same task in the era of tubes and slide rules is another story all together.

  5. #25
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    I have been thinking about this. One of the things that makes my Bridgeport so usable is the swivel, nodding head. I've a KT vertical and man it moves metal, but mostly I use the Bridgeport. Most of the work I do is job shop type work and the versatility of the bp is the go to machine. So the price looks high for what it is but it could make you some $ and for a bit more I'd try to find a machine that is just a good manual machine. Tim

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    I thought of another thing I might add. I also have hydraulic ram style Bridgeport tracer. I learned a lot about milling using it. Some of the things I do it is really handy, i.e. broken housing use the old one as a pattern and make a new one. But I am not sure that it justifies the space cost that it takes up. A machine that would do both is an interesting concept. Tim

  7. #27
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    I'm picking it up Monday. The true trace equipment will come off shortly afterwards. And I'll get some sort of phase converter in the next few fays.

    Sent from my SM-G935V using Tapatalk

  8. #28
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    Quote Originally Posted by 428Bird View Post
    Not familiar with ball screws. Do they use acme threads, because that's what is in the machine. (see pics attached to my first few posts).


    I don't think it was universal but at least some of the better-quality tracer mills used ballscrews. The 2-30 Gorton did, which is why so many got butchered into bad nc conversions

    Quote Originally Posted by timvercoe View Post
    Some of the things I do it is really handy, i.e. broken housing use the old one as a pattern and make a new one.
    Exactly. They kick ass for that. If'n I wuz about twenty years younger I'd go that way. (Very small shop, this isn't gonna work for a even a five man operation.) You can't get replacements for broken stuff no more New cases for your 1923 Indian ? Sure, no problem, bring the broken parts over ...

    By the time you even start modelling a part for nc, the tracer is finished making it.

    Quote Originally Posted by swatkins View Post
    I think I know where one is about an hour west of Houston...
    Thanks Don't tempt me, those are really nice but I think the meter will expire before I could get all organized as a shop again ...

    Quote Originally Posted by ewlsey View Post
    When I was in college I took a Mechatronics course and one of our projects was to build a small robot with wheels that could follow a path on the floor made from electrical tape. ..
    Seems to me there were some systems that could follow a drawing ? Definitely had that for flame cutting. Wasn't too great though, and with nc coming along they disappeared quick.

    It was certainly capable of the kind of speed those tracers ran at
    The limiting factor on speed was the operator's arms, neck, eyes, chest, hair ... Red-hot chips everywhere. They didn't guard machines much until nc controls had been established for ten or twenty years.

    how they did that same task in the era of tubes and slide rules is another story all together.
    Hydraulics. Hydraulics are capable, but messy and noisy. Even many of the early nc machines had hydraulic servos. They just replaced the input from the tracer stylus with a d-to-a converter and some feedback loops to make an nc machine.

  9. #29
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    Quote Originally Posted by SeaMoss View Post

    Hydraulics. Hydraulics are capable, but messy and noisy. Even many of the early nc machines had hydraulic servos. They just replaced the input from the tracer stylus with a d-to-a converter and some feedback loops to make an nc machine.
    My first NC (literally....not CNC) machine was an OKK with hydraulic servos. But what I'm talking about is different... how does the stylus that follows the template automatically "know" that as it starts to come around the outside of a radius to gradually start pressing on the template in the opposite direction of what it was originally and then gradually reverse the Y axis direction as well ? And do so, so perfectly as to leave no excess mill marks or anything ?

    No magnetism involved btw, as I was using aluminum master templates for the comb dovetail templates I was making.



    FWIW, above is an example of what I was making but just an image pulled from the web. Unlike this example, mine had perfect radius on the end of each finger...this one looks a little crude in comparison (although admittedly it's crudeness could be an optical illusion)

    Regardless, my Tru Trace would make three of these at once (3 head machine). All I had to do is get the stylus started for the first cut and then go do something else as the machine would take over automatically from there. Although I did keep checking on it during milling as I was paranoid about one of the three spray mist coolant nozzles clogging in process.

    I only made these on the Tru Trace for a year or two as I was making so many it got tedious so I subbed them out to a teacher at the local technical school where he moonlighted them on a CNC for cheap !

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    Quote Originally Posted by Milacron View Post
    ... how does the stylus that follows the template automatically "know" that as it starts to come around the outside of a radius to gradually start pressing on the template in the opposite direction of what it was originally and then gradually reverse the Y axis direction as well ? And do so, so perfectly as to leave no excess mill marks or anything ?
    TRACER VALVES FOR COPYING MACHINES


    btw, you might consider cleaning your mail out more often

  11. #31
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    Quote Originally Posted by SeaMoss View Post
    TRACER VALVES FOR COPYING MACHINES


    btw, you should consider cleaning your mail out more often
    Ah....that is too cool....finally an explanation of something I wondered about for years. As to "mail" I presume you mean "pm box" which I purposely don't clean out as otherwise I get overwhelmed with newbies wanting their hand held (mixed in with the good stuff) with "how to" forum matters they inevitably figure out on their own anyway.

    I prefer email...note the "contact us" link at the black bar at bottom of every page.

    ===========================

    (on edit) Got your email Sea, thanks, will make contact with him !

  12. #32
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    Quote Originally Posted by Milacron View Post
    (on edit) Got your email Sea, thanks, will make contact with him !
    Hope you can find him : super-cool guy and knows his stuff. All my phone numbers are outdated


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