Cutting a Radius without special tooling

[armorer77]

I have been on this forum for a while and have seen a couple methods for cutting the radius on the base end of mortars , I found this method the easiest .

Find a guage to match the radius you want



Set compound slide to 45 deg. cut to guage



Set comp. slide to 67.5 deg.



Set comp. slide to 22.5 deg.



Sand off the corners .



This gives good results without buying or building any special tooling .



On diameters larger than 3.5" you might want to split your angles again to save on sanding discs .

[KABAR2]

I'd say you've got your system down pat! 

the sander does a nice job of finishing it off,

it looks like your on your way to having quite a few made too!

Are you painting or Parkerizing?

[Cat Whisperer]

Good technique.  Two comments.

I use a cookie sheet under the work whenever I use abrasives to catch the grit.

Good technique to use even when using a radius cutter -  get rid of the bulk of the material first.

[BoomLover]

Those look good, Ed, and that is the same method I use on cutting round ends on wood, works fine! I do like your mortars, and I'll surely like your cannon! Looking forward to delivery! BoomLover

[armorer77]

I am using Hi-Temp BBQ paint for finish , I would prefer a chemical finish , but getting rid of used chemicals in today's political environment No Thank you , as to my quantity , I am building stock for the Montana shoot . Armorer77

[moose53]

You can also use a good file . When held at the right angle you can smoothly remove a lot of metal fast. Saves your sanding disks for finishing.

[kappullen]

Not in common usage today is the "lathe file".

The lathe file has high angle teeth which have a

better tendancy  to clear themselves rather than

building up the bits that score, and spoil your job.

Lathe files are avalible at Manhattan Supply and other

industrial suppliers.

Here's an example of a lathe file;

http://www.brownells.com/aspx/ns/store/productdetail.aspx?p=25663

Kap