Small lathe to make cannons

[firebuckeye]

Does anyone own a small lathe.  The little ones that run on 120 volt and like a 4" chuck?  They go for 500-1000 dollars.  Are these enough to build small cannons?  Is there enough info out there that one could learn enough skills on his own to produce some stuff on a lathe?  I have turned stuff on lathe but it was mostly cnc.  My biggest question is how do you make a radius with a lathe thats not cnc?  This post has several different questions, feel free to comment on any of them.  Just curious.....

[guardsgunner]

I have one of the Chin 9x20 lathes. Does need some tool holder mod. Cannons to 20 oal. and up to about 1/2 scale mortar. keep in ming that it is not a Monach and will not take a 1/4" cut. Takes a little longer. Info every where ,even at the local library. For radius , do the math or make a template and follow it.

[Don Krag]

I have a small benchtop lathe. I'm not even sure what the size is....8 x 18...maybe. It's nice for breech plugs.

A friend has a 9 x 20. It'll turn 1.75" hex about a foot long. We've bored up to .7500 with no problems. As stated above, you just have to take small cuts.

I want a 13 x 40 (220V 1 ph), but don't have anywhere to put it right now.

[accuratemike]

I have the classic $600 Harbor Freight 9x20.
I made this on it http://www.graybeardoutdoors.com/smf/index.php/topic,88832.0.html
http://www.accuratepower.com/Mortar/ .

I had to make a bigger rest to bore the 3 1/2"OD, wasnt too bad. http://www.accuratepower.com/Rest/

To do a radius I used steps. There are alot of ways to arrive at the right co-ordinates for the steps, I use AutoCad and a bunch of parallel lines intersecting the taper or radius, and then the dimensioning tool to find the co-ordinates. Cut a series of steps and then grind, file 'till it is a taper. Or home build or buy a ball turner (swiveling tool post) or taper attachment. I have not seen a 9x20 taper attachment, they essentially are a guide for the lathe that you set at the desired taper and follow. I have also heard of "stopwatch tapering" basically a finer grade of steps, advancing the tool at intervals.
You can do alot with a 9x20, it is a little bit at a time though .
Enjoy, MIKE

[jeeper1]

Here is one way to make a radius.

[GGaskill]

A major problem with a small lathe is drilling the bore of a cannon or howitzer (OK for mortars.)  You are essentially limited to barrels half as long as the length of the lathe as the drill takes up its own length before the bore is started.  Same problem if you bore the bore instead of drill it.  Also the small lathe may not be able to hold the drill or have the power to drill a large hole. 

If you are serious about getting a lathe to make your own barrels, look around for a Logan or South Bend of 36" length.  They don't grow on trees but they are out there if you look hard enough.  While they usually need 220V 3 phase, that is relatively easy to provide.  You need that much size to be able to make a half scale mountain howitzer, which for me is about as small as I want to go, at least in a serious gun.

[CU_Cannon]

I would look for a used lathe over a harbor freight one.  South bend is a good name but imo they are generally overpriced.  People know the name and charge top dollar for machines that aren’t worth the space they take up.  Don’t get me wrong south bend lathes are great when they are in good condition. 

I’ve said this before but get the largest lathe you can afford.  It is no fun to run out of room.  9x20 is a good size to start off with but you will outgrow it very quickly.

[Cat Whisperer]

I have 2 13x38 gap bed lathes each came with 3 and 4 jaw chucks.  Bought them both for $800.  OK, so one doesn't feed, but that means it will be used for other functions not needing the feed - like spcial setups (radius cutting, polishing).

If you can buy used tooling with it you often can get a huge amount of tooling with the machine for one much lower price than by buying each piece one at a time.