Tapers

I need a way to use 1/8" dia. straight shank cutters in a Gorton
pantograph engraver with a taper socket spindle. A ready made collet is
very expensive to buy new, so I was considering trying to make one from
drill rod. The problem is that oddball Gorton spindle taper. Is there
any simple, accurate way to set up to turn this without all the trial
and error? Is it even reasonable to attempt to do this without some
sort of precision grinding equipment? I'm not sure what the spindle
speeds are since the data plate with the information is missing and
they couldn't help at Gorton, other than to tell me the machine (a 3-F)
has not been made since the 1950's, but it takes almost a full minute
for it to come up to full speed and so I'm guessing it could be
somewhere around 15,000 rpm or more. Any advice appreciated.
Mike
Reply to
KyMike
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I've made a few 'matching' tapers, but probably bigger scale than what you need. A few thoughts follow:
Don't use drill rod if not absolutely necessary, hard to machine and get a good finish.
The key to success is to be able to put the work piece back into lathe accurately after making a trial fit.
Try to set up an old collet in such a way that you can use an accurate indicator to align your compound rest to it's angle.
If possible, create the 1/8 bore first, then use a mandrel or between centers to work on the taper. When sufficient length of taper is done, test with Prussian blue to spindle of machine. Adjust compound if required, and so on.
Good luck, Ace
Reply to
Ace
Making something you can spin at that speed requires a little thought. I'd be inclined to make an adapter that takes a collet for a Dremel tool. You'd want to make it of mild steel (not drill rod) or even brass. I've never had very good luck using the compound. I prefer to offset the tailstock, put the faceplate on the lathe, mount the work between centers and drive it with a dog. The nice thing about this approach is that, once you have the recipie down, you can repeat it by simply starting with pieces of stock that are the same length. I made an alignment bar that is just about the maximum lenght the lathe can hold out of 2 in. diameter aluminum with the last couple inches on each end cut and polished to the same diameter. Then I can put a dial indicator on the tool post and it makes setting the offset (and returning the tailstock precisely to center) very easy. You simply calculate the offset required to give you the taper you want, given the length of your stock.
Jerry
Reply to
Jerry Foster
I may have found a source for a used Gorton taper collet. I had the idea that drill rod was supposed to give a better finish, but if I have to go ahead and make an adapter I will use mild steel instead. Thanks for the help everyone. Mike
Reply to
KyMike
Gorton collets come up on Ebay with some regularlty, and cheaply enough. Id not try making one personally for my 3-Z because of the complexity.
Mine comes up to full speed in about 10 seconds. Shrug
Gunner
"Considering the events of recent years, the world has a long way to go to regain its credibility and reputation with the US." unknown
Reply to
Gunner
Robert "teenut" Bastow once described a similar method of realigning one's tailstock using a much smaller device.
Here's a copy of his description:
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In another article he credited Tubal Cain for the method, but it is a cheap and elegant way of doing it and I'm glad he mentioned it.
Reply to
Artemia Salina

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