SpudFiles

So I want to try making some advanced spudgun designs (e.g. semi-auto/auto) which require the use of o-ring seals. Now it is my understanding that if you have, say, a piston and cylinder arrangement that you want to seal with an o-ring, you just cut a groove in the piston with a lathe and put an o-ring in the groove so that it sticks out a little and seals against the cylinder wall.

Unfortunately, I don't have a lathe or anything else beyond the hacksaw and electric drill level of tools. I have read some threads about how to cut o-ring grooves without a lathe, but this did not produce acceptably good results. So I was thinking I could improvise a lathe in the following manner.

Take a bike and jack the rear wheel off the ground. Run an axle though the middle of the wheel and attach the workpiece to the axle. Get someone to pedal the bike really fast, spinning the workpiece. Take a file or saw and touch it to the piece, creating a perfect (hopefully) o-ring groove. Plausible? Necessary?

for me it sounds overly complicated....

why don't you use an electric drill or almost any kind of motor and gear its RPM to acceptable level with the use of a simple set of gears ?

POLAND_SPUD wrote:for me it sounds overly complicated....

why don't you use an electric drill or almost any kind of motor and gear its RPM to acceptable level with the use of a simple set of gears ?

yeah that is much esay than your bike think

I have an old fan motor that fits the bill but I was worried that if I geared it to spin faster I would lose too much torque and it would stall when I started cutting the groove into the pvc, hence the more powerful bike. But if this wouldn't be a problem then I definetely agree it would be simpler.

pvc i think you was talking about metal

ok fan motor can help you . and you dont have to get high rpm . even the mini lathe dont spin like you think http://www.shopping.com/xPO-Steel-City- ... o-3600-Rpm
and the cutting blade she must be steady ( in your case is a file)

You might try making a lego lathe. If you're using small diameter pipes and only cutting o-ring grooves, you don't need something very substantial. If it's not stable enough just glue it together.

You could either have someone spin it for you on a big gear ratio or power it electrically if that's strong enough which is questionable. I would also have it spin some heavy disc so it has some inertia.

It sounds dumb but it might just work.

A lot of things you think you need a lathe for you can actually manage with basic hand tools and a little creativity.

When determining the power and RPM you need, an important question is, what materials will you "machine" on it? Wood, PVC, alluminium or steel? It all makes a big difference.

I'm thinking just pvc right now, which I guess is pretty easy compared to metal.

In that case the Lego thing is not even that silly.

You could use two rollers, made from pipe, a drill and a belt over your workpiece.

build a wooden box with an open front and top.
Drill two pipe-seze holes on each side, about an inch ( or two if you want to use bigger pieces) apart.

Mount the drill in the bottom and put a belt over the head of the drill and your workpiece.

You could make it adjustable too..

if you want to build a really good lathe(meaning it will be used lot!) go to backyardmetalcasting.com the guy there build a lathe from parts he csted him self. i guess it would be a grwat pattime and you would have greath lathe at the end. as a motor use one from an old vacume cleaner or if u want some thing with power take an old washing machine motor!( get em at any dump)

Just clamp your drill in a vice et voila, improvised lather works for me.

As pointed out in the other thread though, by looking into casting techniques you'll find that machining and indeed o-rings are not essential.

Most drill chucks aren't going to hold your work piece very well, plus you have to support the other end of the work piece if its relatively long. Here is a homemade chuck I used to use before I bought my lathe. The center bolt is small enough to fit into a 1/2" drill chuck.

Take a bike and jack the rear wheel off the ground. Run an axle though the middle of the wheel and attach the workpiece to the axle. Get someone to pedal the bike really fast, spinning the workpiece. Take a file or saw and touch it to the piece, creating a perfect (hopefully) o-ring groove.

If you do this, please make a video of it in action. I honestly think it would work, and I honestly think it would be hilarious to watch.

Wait.....did I just post on a thread that was a year old?

Hubb wrote:

Take a bike and jack the rear wheel off the ground. Run an axle though the middle of the wheel and attach the workpiece to the axle. Get someone to pedal the bike really fast, spinning the workpiece. Take a file or saw and touch it to the piece, creating a perfect (hopefully) o-ring groove.

If you do this, please make a video of it in action. I honestly think it would work, and I honestly think it would be hilarious to watch.

Wait.....did I just post on a thread that was a year old?

Yes, Yes you Did... Been happening a lot today... but I will say that the threadkicker has been giving some useful ideas....