Reamer Made to Correct a Large Bore....Reaming successfully completed

[davec2]

I really need another project like I need another root canal......nonetheless, I have begun a refurbishment of the full size cannon I built 50 years ago when I was a junior in high school.  Don't ask me why after 50 years I have to do this now, but there are some issues with the gun that have bothered me for 50 years and if i don't get to correcting them now....well.....i don't need to explain any of that to this crowd.  Moderators, I think this fits under the category of "gun building" but if it belongs elsewhere, please move it.

So, many of you have seen these pictures before, but here is the cannon again for those who may not have seen it.......







One of the things that has always bothered me was that there is a very slight step in the bore about half way down.  Now the nominal bore is 2.75 inches and the step is about 0.005 inches on a radius which amounts to about 0.36% of the bore diameter.  For a cannon, this isn't bad and since I use cannon balls that have about 0.050" windage, the step never really mattered. However, several years ago now, I went back to Pennsylvania to see Ray Rapine about purchasing his bullet mold business. (Another story).  During the course of our conversations, Ray also had a full scale mountain howitzer with a 3 inch bore that he was selling.  Hanging on the wall behind the gun was a target with several 3 inch holes cleanly punched in a 36 inch diameter black bulls eye painted on 1/4" plywood.  He told me he had shot that target at 600 yards with the howitzer.  I looked to see if it was rifled and it was not.  I asked him how he could get that kind of accuracy with a smooth bore.  Ray told me the bore in the gun was very good and that he had made a custom mold to cast zinc round ball that only had 0.003" windage on the diameter of the ball rather than the usual 0.050" or so.  Then he said, "There wasn't much wind that day.  Of course wind don't matter much to a 4 pound ball."  Then he winked.  Ever since I have wanted to get that slight step out of the bore of my cannon and then modify my ball mold to cast a much tighter ball.  There are several other things I want to improve about the cannon (I know a lot more about how things should be now than I did when I was 17 in 1970), but I wanted to start with the bore.


So here is the 6 foot long reamer that I just finished to clean up the bore.  I have to make a muzzle guide yet but when that's done, I should be able to clean up the full length of the bore.










More on the project as this progresses.....

[smylee grouch]

This is starting out to be a really cool thread. 

[Marcruger]

Oh yeah this’ll be a cool thread.  Y’all find a seat. I’m making the popcorn. Go Dave go.

[Tim Crosby]

 The reamer itself is impressive. I can't imagine turning that by hand I can see that handle getting longer.

  Tim

[Daryl]

That is an impressive reamer, Dave. Are you sure the pilot is long enough?
That was impressive shooting indeed.

[davec2]

The original plan was to have a pilot in front of the reamer.  However, the bore for the fist 20 or so inches is line to line with the 2.750" shell reamer.  As a consequence, the reamer will go that far down the bore without needing a forward pilot.  But it does need the guide I am machining for the muzzle that will support the reamer shaft as I work the reamer down through the last portion of the bore.  I have toyed with the idea of opening the bore to a full 3 inches in a similar manner.  In that case I would need the forward end pilot to start.

However, in a moment of sanity, I realized that there is no true "need" for the gun to have a 3 inch bore vs a 2.75" bore.....and if I did take it out to 3 inches, it would cost even more per round for powder and shot (and it's fairly expensive as is.  Even a light load is 1/3 pound of powder and about $12 worth of cannon ball) !!!!

[Ezra]

This is starting out to be a really cool thread. 

Oh yes.  How cool is it that you just back that baby up to the “shooting range” and light her off?!


Ez

[sz]

That reamer HAD to cost some serious bucks.

[heinz]

Wow!  The quest for accuracy in round balls, regardless of size, is a passion.  Have you considered some micro rifling?  Or a rifled sleeve?

Nice work on the reamer.  The handle may be too short for that pitch,

I have every confidence you will get it done.

[Daryl]

What about a delrin or teflon muzzle guide?
Brass would also work, I guess.

[davec2]

Heinz,

Haven't given much though to rifling.  Way back when I tried to patch a cannon ball with a greased rag, I couldn't even get it more than a few inches into the bore.  Had to blow it out with compressed air just to clear the bore.  Without the complexity of making projectiles that engage the rifling mechanically (i.e.lugs on the projectile that mate up to the rifling), or casting projectiles with a lead skirt (like a Minnie ball) it all seemed too much work.  After all, it has taken me 50 years to just advance to the point of trying to ream the bore and cast a closer fitting ball.      And yes, I am not entirely sure I can hand ream the bore, but the barrel is cast iron (which cuts fairly easily) and I don't have to take too big a bite at a time....I'll keep you posted, but wish me luck.

Daryl,

Yes, any of those materials would work as a muzzle guide to keep the reamed shaft concentric with the bore.  I have a piece of 4 inch diameter scrap aluminum round stock, so I think I'll give that a try first.

[Not English]

Dave, I have recently become the curious owner of a 1" bore swivel gun, so I will be following with interest.

Dave

[Robby]

There used to be an outfit in Michigan, if I remember right, that made rifled barrel liners for Parrot cannons and claimed the liner was strong enough to fire as a stand alone.
Robby

[flinchrocket]

I am thinking that you will need a carriage to support the wild end of the reamer shaft. With your muzzle pilot to guide the front, you will not have support on the other end while you are trying to turn the reamer. I suppose you have considered how you are going to hold on to such a large contraption and still be able to rotate it with that long handle??? Best of luck to your endeavors.

[Birddog6]

I don't mean to be negative, but I don't think that reamer will work by hand.  I think you need to drill the bore to within  ? .100" & then ream it.  If it is a very big bite at all, you won't be able to turn it & then also it is going to wedge in & pull in & wedge tighter.  I think you will need a stop on the shaft & cut a couple thousands, back the stop off the shaft a couple thousand more, repeat, etc.

I have a rifling machine & accesseries (bore reamers & etc ).  Haven't messed with the rifling machine much (life keeps getting in the way) but I have used the barrel bore reamers a couple times.  Boy you jam a .50 cal reamer, it is
a sumbuck to get to back out. Thus I imagine a 2.75" one may be impossible to get out if one is not careful.

 

[davec2]

Flinchrocket,

The free end of the reamer shaft will be supported by a muzzle guide....we'll see how this all works out.

D. Keith,

I don't take your comment as negative at all.  I have never done anything like this before so it's all a gamble.  The more advice I get up front the better off I am.  I did provide the option of being able to slide hammer the reamer back out of the bore if it gets stuck !!!! The bore is only constricted by ~ 0.005" on a radius, so I only have to remove 0.010" on the diameter.  The forward end of the shell reamer will do 90% of the cutting over a very short length......so.....I might get away with this.  If not I'll come up with Plan B.  Like the Marines say, "Improvise.....Adapt.....Overcome" !!

Thanks

[Daryl]

I have chambered quite a few rifle barrels by hand. Every one of them turned put very close to perfect. I would have preferred to see more of an angle on the leading edge of the
reamer, but with only .005" to cut out per side, likely it will go just fine, given a well fitting and lubed guide.

[smylee grouch]

Well, I suppose you could trickle some 4f into the flash hole to pop out a stuck reamer! 

[bluenoser]

This is a most interesting project.
Considering the diameter of the reamer, I think a .005" cut should be doable.
You are likely aware of this, but on the off chance you are not - one should never reverse the direction of rotation when reaming or extracting a reamer.  Reverse rotation can result in a chipped or wedged reamer.

[Birddog6]

Oh lord no, you reverse it & all that you just cut out wads up in behind the cutters & you will need
the largest bottle of caster oil you ever saw to get it out.    You really Might have to shoot
it out.

One would think it be like reversing a drill ?  oh heck no.  You back that bugger up & Heck
will Not be one of the words coming out of yer mouth    In fact, may be some words
that come out of there none of us even know 

[DGB]

After forty years of tool and die work, I can tell you that the muzzle guide will be the most important part of this operation. The dia of the reamer compared the cutting length will necessitate the very careful alignment
of the whole set-up.
I don't think the actual turning force will be that great. Like others have said, The .005 is not much for a cutter that size.

Regards,
DGB

[davec2]

Bluenoser & D. Keith.....thanks for the heads up about not reversing the rotation.  No....I did not know that and I'm glad you said something before I got into trouble.

DGB....yes, I will machine the muzzle guide to as close a tolerance as I can and still allow the reamer shaft to rotate freely.  And I am hoping my original assumption that I can turn the reamer by hand for this job is correct, so I appreciate your thought that the turning force might not be too great to do this by hand.  If it is, I have a fall back method.

Thanks again

[Eric Laird]

Have you considered perhaps reaming it vertically? I don't know how much effect the considerable amount of weight in the reamer and handle would have in causing the reamer to "drift" if using it horizontally, but if it were vertical you could rig some pulleys and a counterweight to control feed pressure and gravity might help with reaming concentrically down the bore. You might even be able to rig a gravity flow for lubricant with it running out the touch hole. Of course, as you approached the breach you'd have to pull the reamer and remove the shavings.

Or, I could be completely out in left field....

Eric

[davec2]

Eric,

Thanks for the note.  Yes, my fall back option is to pull the barrel off the carriage and set it up vertically in a frame to do the reaming......so you are no further out in left field than I am 

[Daryl]

Word of caution - clean the reamer often of chips. Always turning to the right as it is removed.
A good oil might help with the cutting, rather than a true thin cutting fluid.  I had better progress with
the new (oilier seems to me) Rapid Tap than with the older stuff or anything else. WD40 actually worked
fairly well, too.