Gort's New Toy

A place for general potato gun questions and discussions.
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sgort87
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Wed Jul 07, 2010 3:21 pm

Craigslist is where I started this adventure. Started the search for a lathe on there and found nothing but garbage, so I went to eBay. It's a good idea to look for tools on there too. I'll keep an eye out.

I'll start lookin for a 4-jaw chuck, but I'll probably hold off till I get this in and play around a bit.
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ramses
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Wed Jul 07, 2010 4:08 pm

You can do small offsets with a 3 jaw, if you shim one jaw. That gets annoying after a while, but it's possible. You will need a 4 jaw chuck to center things well so that features are concentric after you remove parts from the chuck. it is annoying to try to figure out how to do a bunch of operations without un-chucking it. Unless you have a set-tru or "bump-true" setup.
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Hotwired
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Wed Jul 07, 2010 4:28 pm

Probably quite lengthy and therefore costly to sell on but howabout valve blocks.

Square/rectangular stock and mill three ports into it of whatever size/threading needed along with whatever internal stepping might or might not be wanted.

Add piston of choice then screw in pilot, barrel and chamber assembly.
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inonickname
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Wed Jul 07, 2010 9:36 pm

Technician1002 wrote:
sgort87 wrote: I'm not sure I'll need the 4-jaw chuck, unless I decide to do those barrel supports with it.
and
(it was also a rectangular bar in a 3 jaw chuck- don't ask).
The four jaw chuck is the tool to make square stock into round parts. Useful for boring and threading the end of square stock and such. Once you have a 4 jaw chuck you won't know how you got along without one. It's also good for offsets such as making cams since each jaw is individually set. The work does not have to be centered.

A 3 jaw chuck won't do offsets.
I have a 4 jaw chuck. The rectangular bar was a good fit in the 3 jaw(one underneath and two on opposing sides). All I needed to do was get a round section to use. Due to the way it was set up I got a full diameter round bar the exact same diameter I'd have gotten from a 4 jaw.

A 4 jaw can be useful, but setting it up without a lot of experience will often cost you your soul.

For it's size it should be fairly stable...my lathe weighs around 1400 pounds (keeping in mind it doesn't have the milling head sticky taped on :roll:) and there is absolutely no deflection/inaccuracy in it. You should be fine with that.
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sgort87
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Thu Jul 08, 2010 5:59 am

I've been considering getting a self-centering 4-jaw and using wood or something to clamp the work in place. What's your experience with that?
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inonickname
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Thu Jul 08, 2010 6:48 am

Have never used a self centering 4 jaw. The wood could perhaps play around with the accuracy a little.

A self centering 4 jaw will only hold square stock. An independent one will hold a lot more. Also, with an independent one you can center the piece extremely accurately.

I avoid using a 4 jaw if I can anyway. You'll soon realize IF you need it though.
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Technician1002
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Thu Jul 08, 2010 11:34 am

I didn't know that 4 jaw chucks came in a self centering version. If they did, I would rarely use it.
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sgort87
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Thu Jul 08, 2010 11:58 am

A 4-jaw chuck would let one dimension be centered at all times if you stick in 2 diagonal plates. Adjust your piece until it's at the right spot for the diameter you want, then clamp it down. The only thing that it can't do is offset in 2 dimensions, but I can't see myself ever needing to do that. In all the cases I can think of, I need the curve centered perfectly every time, and this will do it with incredible ease.

(Forgive the messy drawing. All the jaws should line up perfectly with the plates, but I'm feeling lazy. I'm sure this will explain it well enough.)
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jor2daje
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Thu Jul 08, 2010 12:49 pm

Well to each his own but I thnk that an independent four jaw chuck can not only do all the thing a self centering one can do, it can hold strange shaped pieces, and like you said can offset in two dimensions. I dont think they are that much harder to set up, with a little practice you can get to within a few hundredths by eye and get it perfectly centered with a dial indicator and a couple minutes.
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Technician1002
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Thu Jul 08, 2010 1:20 pm

Self centering 3 jaw chuck is the workhorse. It is the late equivelant of a Jacobs chuck on your electric drill. When is the last time you fiddled with an electric drill to center the bit? Most round stock work is best in the 3 jaw chuck for that reason. It is fast. I rarely use the 4 jaw chuck, but for the times I use it, nothing can beat it.

If you make model steam engines, or do other machining like that, you will quickly find the value as you cut the cylinder and valve in a single casting.

I consider a 4 jaw chuck a lathe essential and would be lost without one.

It is like having a socket set without a 1/2 inch socket. (10mm for you metric guys) You can do lots with the set, but it is missing an essential function.

Note the bevel on each tooth in the photo below. This will hold bar stock, rectangular castings, etc just fine.
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My dad's 4 jaw chuck.  Each tooth has a setscrew.
My dad's 4 jaw chuck. Each tooth has a setscrew.
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sgort87
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Sat Jul 17, 2010 2:12 am

Well, it finally showed up on Wednesday. The huge crate was dropped in my driveway and sat there until I decided to wake up again, and when I did, it was HOT outside. Me and two buddies popped open the crate and marveled at its beauty... and weight...

I previously thought that each person should be able to handle about a hundred pounds each, and with two guys on two main pieces, it should go up the stairs to my shop fairly easily. I managed to lift the heavy end of the fully-assembled machine off the crate floor about an inch, for about 2 seconds. 441 pounds is a lot heavier than I thought...

We struggled to get the machine apart, working with the conveniently included tools and a couple tools from the house to break the machine down to its main sections. Man, was that a pain in the ass!

The tailstock was the easiest part. That slid right off, as it should. The carriage removal required popping out the lead screw, and the lead screw bearing assembly did not want to come off easily. Next, we had to unwire the mill motor and remove the entire mill assembly. That wasn't too bad, except for the tiny screw hidden inside the belt cabinet that was attached to the mill section. Then off came the cabinet, requiring the removal of the lathe motor from its bracket, popping out a few lathe gears and pulley wheels, and pulling off the lead screw drive box.

About an hour after we started, we had completed the disassembly and muscled it into the back of my dad's F350 to bring it to my shop. (No, my shop is not at home.) Driving the truck wasn't so bad, and the stop for pizza was pretty damn good too, but the next part SUCKED! It still being very hot, we had to carry these things into the building, and up a flight of VERY narrow stairs. One piece, one step at a time, we got all the parts upstairs. The only thing left was the rail, the heaviest of all.

The idea was to continue breaking it down by removing the headstock from the rail. 20 minutes of failed beating, careful assessment, and more failed physical force with bigger tools resulted in us saying screw it, and just carrying it up in one piece. Luckily, we came down in a likewise condition (one piece), just thoroughly covered in sweat, and quite exhausted.

The original plan was to take it apart, bring it upstairs, and reassemble, but a unanimous vote decided to replace "reassemble" with "swim in the pool'. So we stuck to the new plan, and haven't touched it since. :P

One of these days we'll put it back together, unless I suddenly get one of these houses I'm looking at, then I'll wait it out and save us some time, effort, and cursing. In the meantime, I'll be gathering tools for it.

Question: Anyone know of some kind of quick-change adapter that can be bolted to the faceplate and whatever chucks I accumulate so I don't have to keep on bolting and unbolting the chuck, or would it require a new spindle with threads and chucks with likewise threading?
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inonickname
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Sat Jul 17, 2010 3:22 am

You're looking for a cam lock chuck and holder. Takes seconds to swap.
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sgort87
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Sat Jul 17, 2010 6:48 pm

I'm having trouble finding a set of these. Could you point me in the right direction?
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c11man
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Sun Jul 18, 2010 1:12 pm

so gort do you know if you can slide a 1inch tube through it yet? :D
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sgort87
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Sun Jul 18, 2010 1:35 pm

I can slide it in about 8-10 inches.

Wow, that sounds really bad... :shock:
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