Handgonne Contest - Mini Tannenberg (BB scale) - hand tools only

[gulfcoastblackpowder]

Yep...GGaskill has his micro Tannenberg and his full size one, but I'm going to fill the niche of the mini scale!  I've also got another project in mind (it's a secret, but you guys will like it ), but I want to secure some bronze for it (at least SAE660), and that will be harder to find than a trip to Home Depot.

Thanks to him for his plans, because I'm scaling them for mine, so if you want to picture what I'm doing, click here.  I'm not going to reinvent the wheel on this by redrawing it, but if any of you really want my numbers I'll be happy to give them to you, though you can use the formulas I give to calculate them off of the full scale plans linked in the link in this paragraph.

For starters, I wanted to determine that I could easily enough find raw material.  A few calculations allowed me to determine that Home Depot could help, by supplying a 1/2-4.5" SS Bolt:

nominal 1/2-4.5" SS bolt:
.464 in thread
.492 outside thread
shank unmeasured, but larger than thread (I forgot to measure before I started working on it, but will measure the shank after I'm done with the first side - see pictures below.)

Max OD of material at muzzle for octogon shape:
.464*cos22.5=.428

Max OD of material at shank for octogon shape (this is actually a little smaller than actual - see note above):
.492*cos22.5=.455

3/16 bore = .1875 (SF calls for OD=.5625 if no chamber - not sure how I'm going to address this, since I don't know that I can do a chamber, or that I'd want to do one.)

.1875/.6690=.280 scale
OL = 13*.28=3.643

Max OD = 1.594*.28=.447

Max Side width (at Max OD)
.447*sin22.5=.171

Here's the start:
Filing the first side.  Everything will be based on this side, so I stopped after getting tired of fighting off mosquitos.

Beginning work on BB Tannenberg - establishing first side


Fisrt side further along

[GGaskill]

Looks promising.

[Cat Whisperer]

Ahhhhh a masterpiece in the making!

You could wear out that Nicholson Milling Machine that way!   

[rifleshooter2]

Looking good. Remember slow and steady wins the race.

Andy

[dan610324]

remember that always lift the file when returning it
if not there are a hughe posibility that you will destroy the sharp edges
a file is extremely hard , almost as glass
but because of that also very fragile

do it right and you can have a file for several years
do it wrong and you can ruin it in just a few hours

[gulfcoastblackpowder]

Thanks everyone! 

Yes, I'm lifting the file each pass.  I chose to start out with the double cut to get it roughed out, and depending on the smoothness when it's in the final shape I may use a single cut or sand paper to smooth it - or I may just leave the file marks if I like it that way.  I'm carding often too.  I got the files at a great price, but that doesn't mean I want to wear them out!

I forgot to mention (though it's obvious to most of you, I'm sure) - I'm draw filing for this phase.  I'm planning to cut the angles of the profile using a straight file technique, probably finishing by draw filing to make sure all the sides are even.

I thought the stainless may be harder to cut, but it's really not bad.  Of course, it doesn't have a zinc coating or anything else that could make it harder.

When I get the bronze to do the other project(s), I think this will have prepared me for most of that, though they are somewhat more complicated designs.

[gulfcoastblackpowder]

By the way - if anyone has any suggestions or comments on this plan, feel free to let me know.  I've never made a gun/gonne/cannon from scratch before (I made the carriage for my Hern from a single 13' board of oak and the stock for my Morko - which was my first experience with draw filing, but this is the first time I've made a barrel), so you've all got more experience than I do.

[GGaskill]

OK, free advice since you asked.  I would have cut the head off and drilled the bore and socket while it was still round and easy to hold in a chuck.  Maybe can still do if the chuck will grip all jaws on the round. 

Holding an octagon without a four jaw chuck will be a problem.

[Cat Whisperer]

(I REALLY like the low-tech approach)

As you very likely know, a single cut file will give you a smoother finish (if desired) but cuts slower than the doulble cut.

Keep up the good work!  It will be interesting to see how you address each fixturing issue.   

[gulfcoastblackpowder]

GG - I don't have a chuck to mount the bolt in.  The only chuck I've got is the one on my Dewalt hand drill (or older hand drills), and the old ones aren't big enough to hold it anyway - plus, I couldn't very easily drill it if it were in my drill's chuck.  I'm guessing that tip is assuming I've got a lathe?

I'm planning on holding the octogon in the drill vise while I drill it by hand.  The drilling operation is the most questionable part of the whole process, so I do appreciate your attempt to advise.  I did consider cutting off the head and drilling both sides initially, but the reason I got the longer bolt was to give me something to hold onto as I start to shape it, and I figured cutting to length to start would nullify that.  I may still cut the head off so I can more freely position the bolt as I work it more, but for now it's also providing an additional guide for indexing the sides.

CW - I know the single cut would be smoother, but I was looking at doing more aggressive removal, at least for the roughing phase.

[Cat Whisperer]

Keep up the good work!

You've got some challanges - most of us would side step and cave in to using high-tech.

[gulfcoastblackpowder]

I would too, if it were an option!

As it is, it'll probably take a while, especially since I'm going on vacation this week, so I'll be visiting my brother in Savannah for a week.

No progress today, since I worked later than I thought I would, and tommorrow is a hockey game...it'll get done, but I'm not near as quick as you guys with your fancy lathe and press contraptions!

[GGaskill]

I was figuring you would use a hand held electric drill as was done in the M&T thread on the mini-Rodman (unfortunately most of the images are missing.)  I have a couple of plug-in drills with 1/2" chucks but the battery drills are only 3/8". 

[gulfcoastblackpowder]

Mine are actually the opposite - Dewalt has 1/2", corded drills have smaller (haven't checked the exact size).

I remember seeing their homemade lathe.  It would probably be a good idea, but I'd probably need to see the pictures again to set it up.  I guess for drilling, you'd need the chucks of 2 drills - one to hold the stock and one for the bit?  I've turned wood on a lathe, but haven't been around a metal lathe since high school, and even then I wasn't the one operating it.

Seacoast - can you please repost those pictures?

[seacoastartillery]

     Wish we could, but they were all lost in a computer crash that year.  We backup once a week now, but we did not back then.  We also remove the camera memory card when full and save it in a firesafe vault as an ultimate backup, but we did not do this back then.  Silly us.  The two or three pics that still exist give you the idea, besides you are doing fine.  Keep track of your time on task; it will be interesting to know how long it takes the Nicholson mill to do the job.

Tracy & Mike

[Double D]

I have a card reader, I down load all the pictures off the card onto the computer hard drive.  Then erase the chip.

I have a second stand alone 2 terrabyte stand alone Hard drive the I back up the computers on.  That way I have the pictures on my computer to use and on the stand alone hard drive as back up. 

Camera chips are to  hard to work from and too easily corrupted.

[gulfcoastblackpowder]

First day back from Savannah, and it's pouring.  Will get back to this project as soon as the weather cooperates!

Keeping track of time...hmmm...I'll see if I can remember how much time I've spent so far.  Nick's mill is certainly not the most efficient, but it's what I've got to work with.