tank cap o-ring grooves.

[Lance_Wallen]

Question for those who have turned their own delrin/metal tank caps.

I'm tryin to figure out how to get the grooves in my caps for the o-rings that hold it in the tube and hold the carto from leaking. getting the outside one probably wont be that hard, the inside one though... can't figure that out. Tried making a tool for it but to get it small enough to go inside the hole it made it a little too weak, tried again and to bulk it up it couldn't cut as deep as I need to ge the o-ring to seat properly so the carto doesn't just push it out.

I'm doing this on a metal lathe, I've got access to a metal lathe, dremel, variety of things and I'm not opposed to buyin something just for doing this as I plan on making a bunch. Any tips woul dbe appreciated, thanks.

 

[PKZap27]

Here you go!

 

[Lance_Wallen]

did you actually look at any of the results or was that just an opportunity for you to crack an old joke on me? I've googled it. Having bad luck finding anything useful on those results.

 

[PKZap27]

No Joke intended...

I found the following (Second link) using that Google search...

See fifth post down by Harold_V in the following link.

The Home Machinist! • View topic - Possible to Cut O-ring Slot in Inside Wall?

 

[Lance_Wallen]

hrm, hadn't seen that one. Thank you. I tried something similar but my tool ground down very fast. I'll get some better steel blanks I suppose and try again.

 

[Scubabatdan]

Here are a couple pics of the one I made:

It is 1/16" wide and about 1/8" long
Hope this helps.
Dan

 

[Lance_Wallen]

thanks fellas, i'll be posting some pics of my tanks in the next week or so hopefully! I made a similar tool to that but screwed it up, I'm left handed and i do things backwards sometimes ;P I appreciate the help and sorry if I sounded snippy in my first response, was pretty frustrated when I posted and some of that probably came off in the response. Sorry bout that.

-Lance

 

[jrm850]

MSC Item Detail

These work great but be careful when putting it in the tool holder, they are very prone to breaking with too much clamping pressure. These tools are some of the sharpest carbides I have ever seen. I'm usually not a big fan of carbides for one off stuff because I think I get better surface finish with Super sharp HS Steel, but I have no complaints with this tool.

If you grind make sure your relief is a smaller radius that the ID of the bore you are grooving and that your cutting edge is slighly above center when cutting inside.

 

[jrm850]

*** When I said "Slightly above center" I mean a couple thousanths max. If you use the steel ruler trick to set the height of your cutting edge look for a < 3 degree angle.

 

[Scubabatdan]

MSC Item Detail

These work great but be careful when putting it in the tool holder, they are very prone to breaking with too much clamping pressure. These tools are some of the sharpest carbides I have ever seen. I'm usually not a big fan of carbides for one off stuff because I think I get better surface finish with Super sharp HS Steel, but I have no complaints with this tool.

If you grind make sure your relief is a smaller radius that the ID of the bore you are grooving and that your cutting edge is slighly above center when cutting inside.

Good info, but that is for a .097 o-ring groove, kinda big for .0625
Here is where you can get them to make grooves from 1/32"-1/4"
Internal: Internal Tool - Specializing in Carbide Lathe & Mill Tools
External: http://www.internaltool.com/products/product_detail.php?series=73
Dan

 

[jrm850]

Good info, but that is for a .097 o-ring groove, kinda big for .0625
Here is where you can get them to make grooves from 1/32"-1/4"
Internal: Internal Tool - Specializing in Carbide Lathe & Mill Tools
External: Internal Tool - Specializing in Carbide Lathe & Mill Tools
Dan

Yeah that's pretty darn large for an .0625 O-ring. MSC sells the smaller ones also but they don't have them listed under the O-ring cutters. They also cost $58 bucks which makes grinding look a whole lot more attractive.

Thanks for that link... Great prices.

 

[Lance_Wallen]

I'm just gonna grind one. The issue I've got is i'm still unsure of what o-ring to use, I have a few different ones I'm gonna try.

 

[PKZap27]

AS568A Dash Number #011 O-ring

Size 5/16" ID x 7/16" OD x 1/16" Width

Red Silicone McMaster-Carr part # 9396K16

Black Buna-N McMaster-Carr part # 9555K12

 

[Lance_Wallen]

ooh, I have some of those in black. that's good news.

 

[Lance_Wallen]

well mine is o-ring #6 but its the same measurements, it's DANCO

 

[PKZap27]

AS568A Dash Number #011 O-ring

Size 5/16" ID x 7/16" OD x 1/16" Width

Red Silicone McMaster-Carr part # 9396K16

Black Buna-N McMaster-Carr part # 9555K12

Added size and Black Buna-N McMaster-Carr part number with link.

 

[Lance_Wallen]

well, crap. made a cool, cut the groove, put in the oring, the oring didn't seat at first and I had to cut the groove a little deeper and then the ring went in fine. everytime I try to put the carto in though it pushes the oring out. Maybe teh groove I cut is too tapered and needs to be more square?

 

[Lance_Wallen]

yeah, so I finally got a grove 'right' according to the measurements. Those grommets just don't work right, I took apart my liquinators and my big daddy tank and a depth charge. the grommets in them are different than the ones I have (with the measurements above) so I'm gonna hit up the home depot and figure out what they're using cause I'm pretty happy with those tanks, never had leaks and they're pretty easy to take apart and refill, etc. gonna just get those type of orings and try again.