Author Topic: Group buy-group pour, bronze 24 PDR Coehorn golf ball mortar (Read 28296 times)

RocklockI · « **Reply #210 on:** December 02, 2011, 04:44:27 PM »

Well I guess that settles the matter

The standard vent will be .078" for 1/16 or 1.8mm . It looks right for the mortars scale to me .

It is available from any fireworks website and if you are like me and can't diddy bop down to the gunshop for fuse of any size ... so IF you are going to order it just order 1/16" or 1.8mm.

JMHO (but I havnt been wrong yet

)

Gary

Cannoneer · « **Reply #211 on:** December 02, 2011, 09:09:24 PM »

That's it Rocklock, follow your instincts, the smaller diameter vent will look more appropriate to scale on this gb model Federal Coehorn; and if anyone else wants a larger hole, it'll be an easy enough operation to open it up themselves.

Victor3 · « **Reply #212 on:** December 03, 2011, 01:38:38 AM »

Quote from: Cannoneer on December 02, 2011, 09:09:24 PM

That's it Rocklock, follow your instincts, the smaller diameter vent will look more appropriate to scale on this gb model Federal Coehorn; and if anyone else wants a larger hole, it'll be an easy enough operation to open it up themselves.

I agree; smaller vent would be better.

However, while it is "easy enough" to open up a vent in most materials, there's a little trick to not botch it up big time in copper-based alloys. I'm sure Gary knows the secret.

seacoastartillery · « **Reply #213 on:** December 03, 2011, 04:20:50 AM »

Victor, Let's not keep any secrets from the membership. I'm sure you were referring to the fact that an unprepared drill bit will often twist more than "facts to suit theories". When drilling pure copper as we do for every vent liner we make or bronze, in this case, an unprepared drill bit will most likely take off on a wild helical ride to the bottom of the hole and suddenly snap off. This is most disconcerting! To prevent this, prepare your drill bit by grinding a small 'flat' on both cutting edges which is .012" to .015" wide on .078" dia. bits and perpendicular to the drill bit's axis. It's a secret no longer! Gary already knew this, BTW.

Tracy

KABAR2 · « **Reply #214 on:** December 03, 2011, 04:52:48 AM »

The casting looks excellent! so now all we are waiting for is price.......

RocklockI · « **Reply #215 on:** December 03, 2011, 06:09:19 AM »

Yes bronze is abit wierd ,a bit will screw itself into the work . IF any one wants a larger dia. vent I can do it .
The best way I have found to drill it is to lock the spindle on the mill and come up with the table . The bronze cant really bite into the bronze as it can't pull the spindle down as it is locked .

It also can't pull the work up as it is bolted to the table . With a drill press altering the drill is the best you can do . Cutting oil does help and I would recomend it .
Gary

gunsonwheels · « **Reply #216 on:** December 03, 2011, 07:48:55 AM »

Also when drilling a smaller hole into a larger hole... doing it freehand with a portable drill is half the problem with the grabbing/snapping problem. If the workpiece can be mounted in a vise which is mounted on a mill or drill press then the quill of the machine can better hang onto things and prevent them from the rapid "dive/plung/snap".

Best procedure is to grind the negative rake on the bit cutting edges AND enlarge the hole in a press/mill... my opinion anyway... try dilling lead or wheelweight metal for practice

GOW

Double D · « **Reply #217 on:** December 03, 2011, 07:29:26 PM »

I think I need make sure everyone understands what is going on here.

This is a GBOCannons.com group buy. Gary is coordinating the group buy. Gary is not selling these mortars.

Gary will be taking to orders pass to the Foundry and will collect the mortars from the foundry and send them out when they are ready. Gary will also collect the money to pay for them.

If you have any questions about how this all works or want to take part in the group buy , send a PM to Gary.

Gary and I have been working on putting this group buy together for about 6-7 months now. When the deal with the foundry I located fell apart Gary picked up the ball and ran with it and found a foundry in his area to make these mortars for us. Thanks Gary for honchoing the deal!

Cannoneer · « **Reply #218 on:** December 03, 2011, 08:01:52 PM »

Quote from: RocklockI on November 30, 2011, 11:50:16 AM

I will order some more wax and start making some and we'll see how it goes . No firm price yet as it isn't done yet .
Gary

I will gladly say that I definitely want one, and I'm perfectly content to wait for the price, but unfortunately I'm not one of the 1%, so I've got to know the cost before I commit to buy.

RocklockI · « **Reply #219 on:** December 03, 2011, 08:29:38 PM »

Quote from: gunsonwheels on December 03, 2011, 07:48:55 AM

Also when drilling a smaller hole into a larger hole... doing it freehand with a portable drill is half the problem with the grabbing/snapping problem. If the workpiece can be mounted in a vise which is mounted on a mill or drill press then the quill of the machine can better hang onto things and prevent them from the rapid "dive/plung/snap".

Best procedure is to grind the negative rake on the bit cutting edges AND enlarge the hole in a press/mill... my opinion anyway... try dilling lead or wheelweight metal for practice

GOW

So I'm thinking inline !!!!!...not 90% ....!
"W T heck OVER ?" A small hole inside a large hole ,yea OK...? Like two holes in one .....
But with twice the work !
It was almost a flashback moment ,..... I geuss ?

But as far as freehand

..... with a hand drill

, good luck Chuck ! I would not even try it !!!! .

Bronze is sticky and very tough .Today while finishing DD's mortar I had a thought

"..you can't hardly drill the stuff .. , and only barely cut it at all , but if you look at it sideways and hard , it will scratch itself ."

And it will , work with it and baby it in and out of stops , fixtures and jigs and when you are done there are two more scratches on it

.

No clue how they could get there at all ..... Mythbusters should check it out .....

Gary

Victor3 · « **Reply #220 on:** December 04, 2011, 01:17:53 AM »

I think bronze is maybe kinda like salt. Salt being hygroscopic (wanting to absorb water), bronze must be "ferrogroscopic" (wanting to absorb iron).

Cat Whisperer · « **Reply #221 on:** December 04, 2011, 01:50:42 AM »

Quote from: Double D on December 02, 2011, 02:33:20 PM

Of course .178 diameter. Standard over the counter green cannon fuse is 1/8. Quills are 4mm. Standard fare and their no reason for smaller, none.

But there IS a good reason for going smaller. The really-really small fuse is CONSUMED as it burns. So when the big bang occurs there is no flaming-smoking-gloing ember flying through the air.

Drill the hole whatever size so it can accomodate both.

Double D · « **Reply #222 on:** December 04, 2011, 03:06:03 AM »

Quote from: Victor3 on December 04, 2011, 01:17:53 AM

I think bronze is maybe kinda like salt. Salt being hygroscopic (wanting to absorb water), bronze must be "ferrogroscopic" (wanting to absorb iron).

ROTFLMAO!!!!

Double D · « **Reply #223 on:** December 04, 2011, 03:08:02 AM »

Quote from: gunsonwheels on December 03, 2011, 07:48:55 AM

Also when drilling a smaller hole into a larger hole...
GOW

He is saying when you make a smaller hole larger.......

Quote from: Cat Whisperer on December 04, 2011, 01:50:42 AM

But there IS a good reason for going smaller. The really-really small fuse is CONSUMED as it burns. So when the big bang occurs there is no flaming-smoking-gloing ember flying through the air.

Smaller fuse just leaves less ash, nothing more. Still no advantage.

Cannoneer · « **Reply #224 on:** December 05, 2011, 08:40:05 AM »

Quote from: GGaskill on December 01, 2011, 10:56:37 AM

I think it is the same foundry, just a little more careful in cleaning the casting this time. And a less complicated pattern, too.

I'm not following you on this, George. Why do you think it's a less complicated pattern? Other than forming the outside breech area with a shaping tool that was fashioned just for that job, isn't the wax pattern pretty much the same as the first one that Gary turned?

GGaskill · « **Reply #225 on:** December 05, 2011, 10:44:59 AM »

Why do you think it's a less complicated pattern?

Gary had some filigree and a dolphin on the original pattern that didn't survive intact to the finished product. None of that on the plain Coehorn done in Loveland.

RocklockI · « **Reply #226 on:** December 05, 2011, 02:41:41 PM »

Other than George wanting his without rimbases , I wasn't aware of simpler pattern

.

The dolifin gun was the crash test dummy , the dolfin was ...crashed just abit.
I made that one without rimbases so Geroge could see what his will look like

!

Great progress was made today !!!

The much discussed 'Gomer chamber' tool has been made . Due to popular demand it is now standard

.

We are rolling ,
Gary

rampa room artillery · « **Reply #227 on:** December 05, 2011, 03:33:06 PM »

I am just wondering and couldnt find if anyone else ever answered one important question, was the mold oversized for the shrinkage of the bronze?? i am guessing yes, just wanna make sure,
thanks.

rick bryan

RocklockI · « **Reply #228 on:** December 05, 2011, 04:00:22 PM »

Thanks for that question rick , you want one with no rimbases too ?

OF COURSE I TOOK IT IN CONSIDERATION !!!!

What do you think ? You get 'lucky' doing this ?

7%-to 9% is what 'they say' but at this scale 'they' dont know what they are talking about ....but it's a seceret of course .

I am just having some sport here and I mean no offense Rick ,but sometimes

these ?'s ....well they ...make me smile , more than a little thought has gone into this project .

Gary

Cannoneer · « **Reply #229 on:** December 05, 2011, 06:45:55 PM »

Quote from: RocklockI on December 05, 2011, 02:41:41 PM

Great progress was made today !!! The much discussed 'Gomer chamber' tool has been made . Due to popular demand it is now standard .

We are rolling ,
Gary

Alright, this cast bronze, scale model U.S. Coehorn is going to be a bona fide collectible.

Rayfan87 · « **Reply #230 on:** December 06, 2011, 01:49:31 AM »

I'd love to get in on this one, but somehow I'm spending more money with a roommate than I was when I was living alone.

DaveSB · « **Reply #231 on:** December 06, 2011, 04:59:21 AM »

Gary, what's the chance of a dolphin on the mortar?

Cannoneer · « **Reply #232 on:** December 06, 2011, 06:04:46 AM »

Dave,

Gary is making reduced scale reproductions of an actual historic U.S. 24-pounder cast bronze Coehorn mortar, and the originals weren't equipped with dolphins.

Cat Whisperer · « **Reply #233 on:** December 06, 2011, 06:46:59 AM »

Quote from: DaveSB on December 06, 2011, 04:59:21 AM

Gary, what's the chance of a dolphin on the mortar?

DD could do it in 3d and have it printed!

Cannoneer · « **Reply #234 on:** December 06, 2011, 07:07:29 AM »

Yeah, and then you'd not only have a mortar with a dolphin, but also a vent hole that matched the circumfrence of a U.S. dime.

,

RocklockI · « **Reply #235 on:** December 09, 2011, 02:45:52 PM »

Yesterday ,and today went very well

. We changed a few things speeds,feeds, and for the better . Mike made a few suggestions as far as machining and they were good ones .
Here is the Gomer chamber ,it is scale.

This is the finished barrel ,fresh off the lathe . This is the Ike phase of production ,as it looks abit like Ike on South Park

.

SWEET! DD's mortar has a little brother .

I think I have the foundery inline as far as details and making sure the same people work on these mortars each time.

Mike ,Tracy and I went to the foundery a couple days ago . I had the oppertunity to stress important details to the people who will do the casting and that the same people will do each step !

Gary

Cannoneer · « **Reply #236 on:** December 09, 2011, 03:31:30 PM »

That's all good news, and DD's finished mortar looks great.

Double D · « **Reply #237 on:** December 09, 2011, 07:39:25 PM »

I guess DD better start picking up Aluminum cans along the highway to pay of it...

onegreatshot · « **Reply #238 on:** December 15, 2011, 01:49:58 PM »

OK I'm in. This looks like a real nice mortar being made. 1 question, will these mortars be serialized???

1Southpaw · « **Reply #239 on:** December 15, 2011, 03:25:59 PM »

serial killers. ;-)

Poll

I would buy...

Author Topic: Group buy-group pour, bronze 24 PDR Coehorn golf ball mortar (Read 28296 times)