o-ring groove, best way to cut

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jordzan
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Mon Jul 27, 2009 9:40 am

Gday folks, Ive been trying to find out the best practice for cutting a groove for o-rings on my barrel breech design. Had a good search through the breech posts and barrel modding pdf but had no luck finding this info.

Ive got most basic tools and a drill press to get the job done.
greatly appreciate any help :)
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jackssmirkingrevenge
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Mon Jul 27, 2009 9:43 am

jordzan wrote:Had a good search through the breech posts and barrel modding pdf but had no luck finding this info.
Not good enough ;)
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Technician1002
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Mon Jul 27, 2009 11:31 am

Might try this page if your cannon is of a smaller caliber. The cutting pistons info would apply to breech plugs. A tool in the vise can cut a groove in the side of the rotating part. It's how I made my 2 inch piston.
http://www.spudfiles.com/forums/how-to- ... 17899.html
This picture is of making the replacement piston for the Mouse Musket. It doesn't have o rings due to the small diameter. A little grease seals it to the point I had to make a pilot hole in it.

Image
Only a slight variation is needed to cut grooves in the side. Sorry I didn't grab a picture of cutting the grooves. Use a broken drill bit ground to a grooving tool. Mount it in the vise and slide the vise into the rotating stock to cut a groove.

Larger sizes are best done on a lathe.

Picture of a smaller piston with floating o rings. They seal well. These can be cut on a drill press.
Image
Last edited by Technician1002 on Tue Jul 28, 2009 7:33 pm, edited 1 time in total.
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Brian the brain
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Tue Jul 28, 2009 3:02 pm

Damnit...

I just " invented" this myself two days ago...
Did the exact same thing.
When reading the top of the page I was planning of suggesting it..
Seems like you beat me to it.. :D ( I should have followed your work even more closely)

This method ( as I found out for myself :wink: ) works almost as well as a real lathe.On nylon pistons that is.
Some sandpaper will give you a smooth finish.

You can turn down the diameter by securing the stock and just use the press to guide it.

Great How-To Tech!
Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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Technician1002
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Tue Jul 28, 2009 6:46 pm

Brian the brain wrote:Damnit...

I just " invented" this myself two days ago...
Did the exact same thing.
When reading the top of the page I was planning of suggesting it..
Seems like you beat me to it.. :D ( I should have followed your work even more closely)

This method ( as I found out for myself :wink: ) works almost as well as a real lathe.On nylon pistons that is.
Some sandpaper will give you a smooth finish.

You can turn down the diameter by securing the stock and just use the press to guide it.

Great How-To Tech!
The only improvement is to use a cross slide drill press vise for accurate depth cuts and less tool chatter as the vise is bolted down instead of moved by hand. I gotta get a cross slide vise.. :D

Darn budget anyway.. :)
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Mr.Sandman
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Tue Jul 28, 2009 7:01 pm

While not as precise as a drill press or lathe, i use a drill and a vice. Put the drill in the vice snd you get the idea. It works pretty well in fact i just machined a 1/2 piston. :D
Yeah, it's that important.
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jackssmirkingrevenge
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Wed Jul 29, 2009 12:42 am

Mr.Sandman wrote:Put the drill in the vice snd you get the idea. It works pretty well in fact i just machined a 1/2 piston. :D
Poor man's lathe, works fine for me :D
Mogwog
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Wed Jul 29, 2009 4:40 am

How coincidental, just yesterday I was wondering exactly the same thing.

I solved my problem a little differently though. I had to cut an o-ring slot in a couple of 25mm pvc sections so I found some smaller diameter pipe and slid the ring of pvc that i wanted to cut into around that. The ring was not stuck on the smaller pipe at all and was able to spin freely around it. Then I just used my trusty dremel with an engraving bit on it to cut into the ring. The important part is the fact that the ring was spun around the smaller pipe by the already spinning dremel bit which also cut into the pvc at the same time.

The smaller pipe was held by a vice which also doubled as a stopper for the spinning ring being cut. The other side of the ring was held by a spare end cap that was jammed onto the pipe.

I know that this is a really ghetto solution but I was quite proud because it saved me the 10mins or so that it would have taken to set up a "poor man's lathe" and it resulted in a very straight groove in the ring.
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