Bore Finish

[Owen]

Hi Guys

I have a new project on the way. A Widow Blakely gun in smooth bore. What finish do you take the bore to? In the others I have made I use a hole reamer and get a very good finish. Is the necessary? As to do the scale I want it leaves me with a size I don’t have a reamer for and they can be a bit expensive to buy for a single project.

[dan610324]

if you start from just a drilled bore , take emery cloth on a 1/2" tube in an electric hand drill ,
or a wood dowel
attach it by making a notch with a hacksaw in the tube , 2" deep from the top .
put the emery cloth in the notch and wrap it around the tube
fill the bore with kerosene and start with 180 grit ,
then continue with 240 , 320 , 600 , 800 and finaly 1000 grit
then you will have an almost mirror finish in the bore

but be very careful to move it in an equal speed all the time
so you remeve the same amount of material in the bottom of the bore as you do in the muzzle area
the better finish you get in the bore the better cannon
and a lot easier to clean

[GGaskill]

I think 1000 grit is a lot overkill.  You should consider using a couple of different grit Flex-Hones on a drilled bore.  I would stop at 320 grit myself.

[seacoastartillery]

     Owen, first you have to decide if this is to be a serious shooter with an excellent potential for accuracy or not.  If it is to be as accurate as you can make it, then it's gundrill time followed by a push reamer, the best you can afford.  No need for any polishing if you clean out the chips continuously.  Polishing or even lapping can do more damage to a well reamed bore than most people know.  If it's to be a good looker or casual shooter, then any of these methods mentioned will do it.  We only have experience with the BC Flex Hone which does a good job.  Don't expect any real metal removal, however, only polishing of a pretty smooth bore to begin with.  We found that they will only remove one or two tenthousanths of an inch .0001-.0002" maybe .0003" if a coarse grit is used first.  If your twist-drilled bore looks like a mechanical beaver drilled it with big swirly scratches, etc., then forget it or make a really nice tompion and say, "Sorry, I have to keep this in place to protect the mint condition bore against humidity which could cause rust". 

Tracy and Mike

[Owen]

I think ill go with a new reamer. I would like it to be as accurate as I can and any reason to buy new toys and I can make more cannons in that size .... and as where I live I can only have cannons with a max of 10 gauge or 19.8mm ill get a 19mm reamer and push it as close as I can so should not be to bad to buy a good one.


thanks for the advice

[Cannoneer]

fill the bore with kerosene and start with 180 grit

Dan,
Why kerosene?

[GGaskill]

Why kerosene?

Keeps the emery cloth from loading up with swarf.  Readily available, at least traditionally, and not too volatile so not too much of a fire hazard.  Kerosene was used as a cutting fluid for aluminum for a long time until the rise of OSHA and such things brought on water based cutting fluids.

[dan610324]

yeah exact , also used when honing a cylinder for example , maybe mixed with a few % oil
for aluminum I always use alcohol

[Cat Whisperer]

yeah exact , also used when honing a cylinder for example , maybe mixed with a few % oil
for aluminum I always use alcohol

I use methanol and ethanol for aluminum too.  Methanol during and ethanol after. 

[dan610324]

vodka , whisky or rum after ??
the rum gives the work a much better look
but if you use too much of it the surface can easily be a bit blurred 

[Cannoneer]

I always use alcohol

Dan,
I'm not saying a word , even though the temptation is so great that I've got my hands clasped together tightly, as if in prayer!    This is, in my opinion, proof positive that free will exists.


Would WD 40 work for this, or would it clog up the emory cloth?

[dan610324]

drinking WD 40 ??  dont think thats any good idea 
well maybe with coke

sorry couldnt resist

WD 40 would probably be ok , I guess most of it is kerosene any way , or something very similar
but it would be unnecessary expensive
half a gallon of kerosene will last a lifetime for most people

[Cannoneer]

half a gallon of kerosene will last a lifetime for most people

Seriously: That's what bothers me about it; I'll use a tiny amount and then the can's going to be sitting in my garage for a quarter century. I'm going to give the WD 40 a try (that's what I used when I bored a small brass barrel with my drill press).

[Zulu]

Boom J,
What are you honing?  Iron? Bronze?
Would bronze be honed the same way as iron?
Zulu

[Cannoneer]

The barrel I'm going to hone is steel.

[dan610324]

what diameter is it ??

when I dont have a reamer that fits I cheat by first drilling but save 0,2 millimeter from finished diameter
then I pump in a lot of motoroil and drill it again at a much higher rpm and a minimum feed with a drill that leaves 0,05 millimeter from finished diameter
then I use emery cloth as described in the above post

with some practice you can get a decent result , not perfect but decent

if its a little larger diameter I would buy a honing tool , those with 3 arms and honing stones .

[GGaskill]

I have used WD-40 as a cutting oil for aluminum because of convenience, but I would think it is a little thin for use with emery paper as described above unless you buy it by the gallon and can fill up the hole while you are "honing."  I think it would drain off the paper too fast.

[dan610324]

fasten the barrel in a vise at a 45 degree angle with muzzle up
fill the bore to approximately 30% with kerosene and do the honing

[Josco]

To improve the finish on drilled holes  stone a small radius on the drill where the cutting edge intersects the diameter of the drill. This will prevent the sharp corner from breaking down too fast and galling the hole. An old toolmaker taught me this years ago and it does work.

[Cat Whisperer]

To improve the finish on drilled holes  stone a small radius on the drill where the cutting edge intersects the diameter of the drill. This will prevent the sharp corner from breaking down too fast and galling the hole. An old toolmaker taught me this years ago and it does work.

These are the tricks of the trade to accumulate.   

[Cannoneer]

what diameter is it ??

when I dont have a reamer that fits I cheat by first drilling but save 0,2 millimeter from finished diameter
then I pump in a lot of motoroil and drill it again at a much higher rpm and a minimum feed with a drill that leaves 0,05 millimeter from finished diameter
then I use emery cloth as described in the above post

with some practice you can get a decent result , not perfect but decent

if its a little larger diameter I would buy a honing tool , those with 3 arms and honing stones .

It's .75 caliber, bore length 13.5'', 16'' OAL, and machined out of 1015 solid stock. Keep in mind that I don't have a lathe, all I've got is an old 'Craftsman' drill press.

[Zulu]

Boom J,
Will it have a shape?  Are you using files?  This is very interesting.  What did you have to do to get the bore straight?  That would have been one of my problems using a drill press.
Zulu

[dan610324]

with some luck you can find a very small honing device for hydraulic cylinders to old drum brake cylinders
that might work in a 3/4" bore
at least try to find one and check if it can handle that small diameter
but run it with a hand held electric drill

[GGaskill]

A drill press would drill the hole pretty straight, just not necessarily down the center of the bar.  For anything under an inch, I would either get a reamer slightly larger than the drill and ream the bore or, if you don't want to spend that kind of money, try the suggestion about radiusing the corner and use the next larger drill down the bore.  When removing a small amount of material, a drill can do a pretty smooth job.

[dan610324]

yeah thats why I always save 0,2 millimeter or so from the finished diameter for the last cut and honing
I have never tried the radius on the corners , but will do the next time

[Cannoneer]

Boom J,
Will it have a shape?  Are you using files?  This is very interesting.  What did you have to do to get the bore straight?  That would have been one of my problems using a drill press.
Zulu

Zulu,

I haven't done anything with this barrel yet, this is exactly how I got it from another member who originally got it on eBay. It's the top barrel in the photo, and if I were hard pressed to answer what kind of gun the machinist who made it had in mind as a model, I guess I would answer a Parrott; that is very loosely patterned after a Parrott.  

[dan610324]

thats a bunch of very nice barrels

[Zulu]

Parrott or not, it still looks sweet!
Zulu

[Cannoneer]

Thanks. A new 15'' long drill of the right diam. actually costs more than I paid for the barrel, but I located a used 49/64'' HSS 18'' long drill on eBay (they guarantee its condition ), and I think I'm going to get it and try the radiused corner suggestion.