Order of operations and general approach question on this small part

[ChazzC]

Leave it long and mount it in vise standing up . You could use an end mill to plunge , or use a boring head for the radiis . Not sure what tooling you have on hand .

That was my thinking, but waiting for more experienced folks first. With my LMS 3990 Mini-Mill, table to spindle nose is 13-1/2, including 2" Riser Block, less 1-7/8" table to bottom of vise (plus 7/8" tall jaws). My 1/2" Boring head sticks out 3", and my 1-3/8" cut bar sticks out at least 3/4". Even without the Riser Block, my boring head would work, assuming @ssdesigner leaves an extra 1" to grab in the chuck.

However, due to the lack of rigidity of a Mini-Mill, I would go with 1" & 1/2" end mills, making the 1/2" radius cut first to have the most material backing up the cut. I would also make multiple plunges for both radii, gradually eating away at the stock (I made 7/8" radius cuts in a 9/16" thick 6061 fluted knob and 3/16" radius, 2-1/8" deep relief cuts for SHCS's this way – took a little time, but came out perfectly). The radii may not be as accurate using the end mills as could be achieved with a boring head on a larger machine, but with a Mini-Mill it's a toss-up. Also, even with the multiple passes with the end mills, it will still take less time than with a boring head.

I used 4-flute end mills.

 

[ChazzC]

Thanks for that info. My end mill set (goes up to 3/4” as I mentioned) are all center cutting.

I’ll pick up a 1” center cutting end mill. I will need that going forward for another project.

I suggest getting a 3/4" shank 1"Ø end mill so that you won't need a longer end mill than necessary, and check that your existing 1/2"Ø end mill has more than 1-1/4" cutting length.

The cuts I referred to in post #11 were in projects published in Home Shop Machinist with lists of photos if that helps.


Charlie

 

[ssdesigner]

Well it turns out LMS has their pro grade R8 boring head on sale. I picked that up for future flexibility. Time to learn how to use a couple of new tools! I didn’t have a fly cutter either for facing so I picked that up as well.

Or do people use the boring head for facing?

 

[mmcmdl]

Or do people use the boring head for facing?

Boring head isn't balanced and would shake the mill to death at high RPMs .

 

[ssdesigner]

Boring head isn't balanced and would shake the mill to death at high RPMs .

Glad I asked, lol. Thanks!

 

[mmcmdl]

Glad I asked, lol. Thanks!

I've seen lathes walk across the floor with bar whip . Seen mills and drill presses end up on their side as well . Pretty wild to watch !

 

[ssdesigner]

I've seen lathes walk across the floor with bar whip . Seen mills and drill presses end up on their side as well . Pretty wild to watch !

That is equal parts hilarious and terrifying.

 

[C-Bag]

I’m curious why if it’s just a prop you can’t just use some aluminum paint on your original part and call it good?

 

[ssdesigner]

I’m curious why if it’s just a prop you can’t just use some aluminum paint on your original part and call it good?

Because just about anybody can do that

The gun is Inara’s pistol from Firefly. I purchased a real, stainless steel Luger for this build so no plastic allowed

I’m not averse to plastic parts though. Lots of my props are made thst way. This one needs to be all metal though.

 

[C-Bag]

Because just about anybody can do that

Uh, I disagree. You had to use a 3D printer to make that so that counts me out as I’m not a heavy CAD user nor 3D printer buff. We who actually make stuff tend to think everyone does but not true by a long shot.

I sporadically watch Adam Savage’s Tested and he has all kinds of movie props and most seem less than functional so that’s why I asked. I get now it’s a personal decision and I respect that, was just curious.