Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 62 users online :: 4 registered, 1 hidden and 57 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

o-rings and tolerances questions

A place to ask general spud cannon related questions.
Sponsored 
  • Author
    Message

o-rings and tolerances questions

Unread postAuthor: cfb_rolley » Thu Sep 23, 2010 3:51 am

so i'm currently half way through designing my new advanced combustion, and i do have access to a machine shop that can do CNC machining for me, so most of the parts i'm planning to have custom made.

the problem I have run in to is that i don't know the tolerances for a good fit of the fixed fittings to be glued to pipe, and whether or not the fittings need to be tapered.

also, i have the bolt sliding inside the chamber, so i was planning to use o-rings to make a seal, same deal with a vent port that opens by sliding and aligning 2 holes. for that, are there standard sizes of o-rings that are readily available? and also how tight should they fit to be able to move but still make a good seal?
  • 0

Attachments
bolt and orings.jpg
bolt and orings.jpg (38.86 KiB) Viewed 402 times
User avatar
cfb_rolley
Master Sergeant
Master Sergeant
 
Posts: 166
Joined: Tue Mar 24, 2009 11:11 pm
Reputation: 5

Unread postAuthor: POLAND_SPUD » Thu Sep 23, 2010 9:58 am

I am new to solidworks but it seems that it has a library of standard o-rings and oring grooves. I guess that autoCAD has them too
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5405
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 10

Unread postAuthor: Technician1002 » Thu Sep 23, 2010 10:07 am

One of the best resources for this is RL Hudson O-Ring Design & Materials Guide. It covers the common sizes, dynamic seals, and common clearances used. The guide is complimentary.
http://www.rlhudson.com/publications/pub_orings.html
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: ramses » Thu Sep 23, 2010 4:47 pm

You only probably need 1 o-ring

Google for "oring size chart"

Depending on what you actually want to accomplish, you could possibly get away with just a tight, lubricated fit.
  • 0

POLAND_SPUD wrote:even if there was no link I'd know it's a bot because of female name :D
User avatar
ramses
Major General
Major General
 
Posts: 1679
Joined: Thu May 29, 2008 6:50 pm
Reputation: 3

Unread postAuthor: cfb_rolley » Mon Sep 27, 2010 10:21 pm

Ah sweet. I'll probably just do that and groove it for o-rings later, the plan is I'm going to use shells with o-rings as well, and use a burst plate at the back of the shell so I could use it as a hybrid as well.
  • 0

User avatar
cfb_rolley
Master Sergeant
Master Sergeant
 
Posts: 166
Joined: Tue Mar 24, 2009 11:11 pm
Reputation: 5

Re: o-rings and tolerances questions

Unread postAuthor: velocity3x » Tue Oct 05, 2010 6:49 pm

cfb_rolley wrote: i do have access to a machine shop that can do CNC machining for me


are there standard sizes of o-rings that are readily available? and also how tight should they fit to be able to move but still make a good seal?


I'm sure your machinist has a copy of Machinery's Handbook. In it are tables for static and dynamic o-ring selection and installation. The machinist can quickly determine the bore, gland and o-ring size required for a dynamic o-ring install.
  • 0

User avatar
velocity3x
Brigadier General
Brigadier General
 
Posts: 827
Joined: Fri Jun 05, 2009 3:09 pm
Location: Yuma, Arizona
Country: United States (us)
Reputation: 7

Return to General Spud Cannon Related

Who is online

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'