Inletting a cannon base, basics

[Double D]

We have mentioned this technique in a number of posts but I thought open this separate topic to collect tips.

I'll start with the way I do it and others can join in with their techniques. Then maybe we can get the Mods to insert a link to this post  in the reference sticky where we have collected a number of these type posts over the years.  Sorry Mods but the honeymoon is over and it is time for you to earn your pay!

To inlet a base I use  good quality sharp chisels, scribe, rawhide mallet, combination square and a sharpie-magic marker.



I use the sharpie to blacken the portion of the barrel that will be in contact withe wood. You can us candle soot, printers ink, inletting black and just about anything else that will contact transfer from the barrel to wood.

Place the barrel on the base and gently tap in with the mallet.



Lift the barrel off the base and look for the black transfer to the wood,



Us your chisel to cut away the black only.



Use the head of you combination square to check the angle as you go.



When you get to 45 degrees stop!



Here is some examples of my inletting.








Here is the real secret to making this easier to do-sharp tools.  Make sure your chisels are correctly sharpened and keep them that way.

[smokemjoe]

 I wish to add, keep the cross bolt low so  you dont  hit it when you put your 45 deg. My bowling mortar lays on it at 45 deg. On it I also put in a 3/4 in. die spring in the back side for when it recoil  back under a full charge. Good job DD, Make me want to make another one, I am wiping this lung cancer.

[lendi]

nice job Double D.
 I have done several mortar bases and mountain howitzer carriages.  look into getting a in-cannel gouge.  it is sharpened  on the inside of the tool.  check "two cherries" as a supplier.  i picked mine up from ebay.  it makes the job much easier.

lendi

[Double D]

Thanks lendi, I have been looking for one of those!!

[Double D]

nice job Double D.
 I have done several mortar bases and mountain howitzer carriages.  look into getting a in-cannel gouge.  it is sharpened  on the inside of the tool.  check "two cherries" as a supplier.  i picked mine up from ebay.  it makes the job much easier.

lendi

Got my Henry Taylor in-cannel gouge today.   Going to take a bit of learning. Been using a traditional out cannel  gouge...this one cuts nice, but then it is new adn sharp.

Thanks lendo for the tip.

[jeeper1]

What is a "in-cannel gouge"? Pics would be helpful.

[The Jeff]

What is a "in-cannel gouge"? Pics would be helpful.

An in-cannel gouge is sharpened on the concave side, while the out-cannel gouge is sharpened on the convex side.

[jeeper1]

Thank you.

[Double D]

Common configuration or out cannel on left, in cannel on right.

[Double D]

[Double D]

Another 6 minutes....

[Zulu]

Very interesting!  Obviously, One would have to have possession of the actual mortar to do the inletting.  I don't see any other way to do it without the mortar.
Zulu

[GGaskill]

I don't see any other way to do it without the mortar.

Depends how close to the print the mortar actually is.  If you were doing lots of bases, you could figure out what the basic size is and rough out the majority of the material mechanically and only have to do the final fitting with the chisel (that is, if you didn't have a Bridgeport.)   

In the half scale Coehorn I did, the inletting took almost as much time as all the rest of it except making the handles.

[Double D]

Crank the head over on the mill and plunge big ball end milling cutter.

FWIW I have about 40 minutes into it now. 

 

[dominick]

Douglas,  Good instructional videos!  Thanks for taking the time to make it.
 
When I sell a mortar barrel, I have a template sheet that is enclosed with the instructions for rough cutting the barrel fit.  I use a die grinder to notch for the barrel.  It's easy to cut too much with it though. I like your chisel method better.

Bed with template.
 

[Double D]

Template helps gets started.  The final shape of the inlet will be elliptical. I start by just tracing around the base with pencil.



It took all told just under two hours to do this.  If it weren't for my old arthritic hands might have only taken an hour and a half.   The  way the hands feel, it will be Monday before I start on the next one.   I have another K.I.S.S. mortar to do.