Gorton pantograph help

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jscarmozza
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Gorton pantograph help

Post by jscarmozza »

I just acquired a nice (and heavy) Gorton P2-2 pantograph. I planned to use it more like a router/milling machine than an engraver to make casting patterns and small parts. That being said, it has the potential, if I can master it, to do a lot of neat things. From reading, watching you tube and playing with it, I came to the conclusion that I may not get to the finished result in one step, is that a correct assumption? It appears that you have to sneak up on the finished product by changing the cutter and stylus, is this what has to be done as the the reduction gets smaller and the detail finer? I also read that the cutter and stylus diameters affect the work as the reduction ratios change, but haven't mastered that concept yet. This is one of the few machines that other club members don't have much experience with, so I'm flying by the seat of my pants (but anxious to get to it).
John
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Harold_V
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Re: Gorton pantograph help

Post by Harold_V »

I've spent very limited time on a pantograph, which was also a Gorton. The only thing I can say is it takes a little experience before you can operate the machine without making mistakes, especially if you're engraving text. All too easy to cut lines where they're not wanted.

For pattern making, you must keep in mind that the cutter and stylus must be identical. Much the same as when operating a hydraulic tracer. Any difference between them will manifest as altered dimensions.

I had a keen interest in obtaining a Gorton until my wife encouraged me to purchase my CNC mill, which eliminated the need.

Nice machine you acquired.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
jscarmozza
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Re: Gorton pantograph help

Post by jscarmozza »

Harold, I anticipate a lot of trial and error before producing anything of value. I down loaded an instruction book and have been trying to make sense of it. As long as I have the book in front of me I can setup the reduction ratios on the pantograph arms, but the stylus cutter relationship is a little more tricky. There were also charts in the instruction book that traced the limits of the stylus for each whole number reduction ratio, it answered my question about doing the reduction in steps. If the template is outside the travel limits of the stylus for the reduction you want, then you have to do it in steps. Like Cool Hand Luke, I'm going to have to 'get my mind right' before working with this machine:)
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Harold_V
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Re: Gorton pantograph help

Post by Harold_V »

I suspect you're going to do just fine. What's important with machining is to concentrate and make wise moves (the old adage to measure twice, cut once). When you've gained enough experience, you're going to really appreciate the capabilities at your disposal. The only real negative is the need for a master, but it can be made of plastic, for easy machining. Plenty good enough, even for more than one-off, and the added benefit of any errors you might make in the pattern are correspondingly reduced. You can achieve relatively high precision with little effort.

I'd enjoy hearing more as you progress.

H
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liveaboard
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Re: Gorton pantograph help

Post by liveaboard »

Harold_V wrote: Thu Sep 17, 2020 3:06 pm my wife encouraged me to purchase my CNC mill,
H
Sounds like a keeper!
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Harold_V
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Re: Gorton pantograph help

Post by Harold_V »

liveaboard wrote: Fri Sep 18, 2020 7:44 am
Harold_V wrote: Thu Sep 17, 2020 3:06 pm my wife encouraged me to purchase my CNC mill,
H
Sounds like a keeper!
She is! (Most of the time, anyway!) :P

H
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Russ Hanscom
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Re: Gorton pantograph help

Post by Russ Hanscom »

not safe - all of the time!
jscarmozza
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Re: Gorton pantograph help

Post by jscarmozza »

This thing has potential Harold! That's the beginning of a pattern for a fixed coupling, a total of 1-1/2 hours work. It took me longer to make the template than to trace out the pattern.
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Harold_V
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Re: Gorton pantograph help

Post by Harold_V »

Yep! I agree! They do have potential, and I'd have gladly welcomed one to my shop had circumstances been different.
There was one of the Gorton 3D models (I do not recall the model number) in the tool and die shop when I worked (briefly) at Tooele Army Depot. Amazing tool!

H
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jscarmozza
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Re: Gorton pantograph help

Post by jscarmozza »

When I got this machine it came with a big box of spare parts, round cotton drive belts, a spare spindle and most importantly, three additional collets...unfortunately, most of the parts, the collets in particular, are for a Deckel pantograph. So the only Gorton collet that I have is the 3/8" collet that was in the spindle. In the collet was a sleeve with a tapered bore and a tapered shank engraving tool, still available from Famco but ridiculously expensive. So, I took a shot at making a collet and it didn't turn out very well...too much run out. I'll tell you what I did and would appreciate it if you tell me what I did wrong. I started with 'stress-proof' steel and held the work piece in a collet with live center. I turned the outside taper and grooves, then drilled and reamed the 1/4" tool hole, leaving gripping extensions on each end to hold the piece for drilling and slitting. I then mounted the piece in a fixture, drilled the six relief holes and cut the six slits in the collet body, photo attached. It held the tool just fine, but I could hear and feel the run out vibration in the spindle. I was thinking that for my next try, I'd drill and ream the hole first, mount the work on a mandrel and proceed the same way but with the work between centers...any thoughts on that?
John
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Harold_V
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Re: Gorton pantograph help

Post by Harold_V »

What you did wrong was drilling and reaming. It's hard to understand, but that's no way to generate center, in spite of the fact that it is commonly done.

If you hope to achieve a true running collet, it is important that you bore and turn the piece without removing it from the machine. Only by boring can you ***guarantee** that the two features will be true to one another (and then only as true as the bearings in the machine). If you achieve that condition by simply drilling and reaming, it will be by chance.

Alternately, you can make the proper setup on a universal grinder with internal capabilities, but the same thing is true. You must do the operations without removing the workpiece from the machine. It's very difficult to align the work so it ends up concentric and parallel if you don't.

That's a pretty piece of work. Too bad it isn't concentric and/or parallel.

H
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jscarmozza
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Re: Gorton pantograph help

Post by jscarmozza »

Thanks Harold, I'll do it again but bore it Instead. I'll let you know how it turns out. John
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