Standard for vent sizes?

[Rock6.3]

What is the rule of thumb for determining vent diameter?

My golf ball Coehorn will be using fuse that is .116" diameter.

I've seen a callout of 1/64th of an inch larger than fuze in one document, 3/16 of an inch in another, is there a standard?  (these two citations vary from .1316" to .1875)

Is there a standard, or a rule of thumb other than the obvious (at least as large as the fuse)?

[buzz36]

i usualy make mine size of fuse witch 1/8 or i used a 3MM bit
my last canon i made it little bigger  and two things  i notices one is i never have to clean the vent but  the fuse will spin if its got a curl to it
 

[Double D]

I just posted this reference vent holes in another post.  To lazy to retype.

Standard over the counter cannon fuse is 1/8".  Yes, you can buy smaller but if the local gunshop has fuse it most likely will be the 1/8" stuff.

Some preach use smaller vent to prevent excessive low of pressure. The loss of pressure with the smaller/smallest of cannons my be a relevant issue.  If your cannon is .50 caliber or larger, the loss of pressure with the  larger vent is insignificant, in my experience.

What I have experienced with the smaller vents is they foul more and are more difficult clear and clean.

One of the arguments for the smaller vent is that it looks better...that to me is an invalid argument.

Make your vent .177 especially in this larger cannon.  You will be able to use the straw quills in that size.  Friction primers require an even slightly larger vent.

Your golf ball cannon is probably to light for friction primer.

[Rock6.3]

i usualy make mine size of fuse witch 1/8 or i used a 3MM bit
my last canon i made it little bigger  and two things  i notices one is i never have to clean the vent but  the fuse will spin if its got a curl to it

Something is wrong here.  A 1/8" fuse is .125"
3mm is .118110"

Use of a 3mm bit for a 1/8" dia fuse would result in a vent that is smaller than the fuse.

[armorer77]

Try a #29 drill .  .136 dia. Easy to find at hardware stores . It's the tap drill for an 8-32 screw . Ed

[flagman1776]

My coffee stirrer quills are a touch over 1/8", What clears them clears green cannon fuse.

[quickgun]

My coffee stirrer quills are a touch over 1/8", but what clears them clears green cannon fuse.  Someone gave me some red fuse but I passed it on as it would not fit & I refused to open the touch holes more.

Just curious but what do you use the coffee stirrer quills for on your cannon?
Carl

[Double D]

The plastic coffee stirrer quills are used by those folks who haven't  been on the cannon link list sticky to find a source for the paper straws.

Paper straws are 4mm.

For the vent get a #16 drill  which is .177.  You could also get a 4.5mm drill which .1772 diameter

[quickgun]

Okay, I've actually spent time perusing all the stickys but would now like to know, what are the soda straws used for in cannon building/firing?


As you can tell by my post count I am a newby here and trying to learn.


Carl

[seacoastartillery]

     Quickgun,    Use the following link to learn exactly what paper straws are for.  These provide instant ignition so light ONLY with a linstock!!  DO NOT light with a match or a lighter!  We make our quills this way and never had one fail.

                                               http://www.gboreloaded.com/forums/index.php/topic,95774.30.html

Read Reply #36, the one with nice photos.


Tracy

[quickgun]

Thanks much Tracy. Your help, as well as all those here, is much appreciated.


Carl

[flagman1776]

Delete

[buzz36]

rock i mis wrote it
the brill i use is the same as for a 3mm screw sorry my bits landed on the floor and i never got them back right