80% Receivers On A Lathe Milling Attachment???

[cdhknives]

Plan A is a bust...the throat of my milling attachment is about 1/4" too narrow to fit the jig with the receiver installed. Since I don't want to try and thin the jig or open up the milling vise, I'm on to plan B, lots of shims/blocks/etc on a t-slot cross slide I am finishing the fit up on.

 

[ScrapMetal]

Just remember to take and share pictures along the way. It's always interesting to see how someone else solves a problem.

-Ron

 

[cdhknives]

You asked for it...

Getting started...after spending an hour trying to get shims and blocks to work for setup, I realized that was making things WAY too complicated, so I went back to plan A, the milling attachment.

I had to shave a bit off the bottom of my mill's clamp...not much more than taking off the machining marks. That thing was poorly finished! The throat of the clamp was slightly too narrow and this also was an opportunity to square everything up. It took less than I expected to get the jig to fit inside.


When I clamped it, the jig wanted to rock and there is only the little bolts holding the end together, so I added a clamp to take the load off the bolts.


This is probably not the best way to set depth, but lacking a DRO or a traverse dial on my lathe, I am left with this...clamping a metal ruler on the bed and setting a travel stop. The compound would work, except it comes off to install the mill.



I decided all the small holes on template #1 were unnecessary but might be handy at the perimeter, so AFTER pricking each spot I started drilling the middle out with a 5/16". That should reliably leave perimeter metal for final cuts.

I might have time to finish all the drilling to hog out metal tonight. Next comes actual milling...and yes I'll be a lot more careful setting depth. I made sure to come up a 16th or so short on all my drills to insure the final cuts will all be from the mill.

 

[ScrapMetal]

Looking good so far. When you get to the final milling out of the fire control group might I suggest that you hold a shop vac nozzle up to the cavity while milling it out? (Ignore this if you already planned for that. ) Your finish milling will come out a LOT nicer if you keep the swarf removed while doing it.

JMHO

-Ron

 

[cdhknives]

DONE! Well, the making swarf part is done assuming once it is built everything checks out!

Conclusions: Pecking all the small holes is worse than a waste of time, and it does waste a lot of time. Chatter was much reduced when working on continuous webs. I could cut 1/8" passes with minimal trouble once I got past the drill holes, but had to take much smaller cuts due to chatter when working in webs between holes. The milling attachment is less than ideal but it works with a lot of patience and care in setup.

It turned out about as good as I have aright to expect. There are some extra marks in the sides of the pocket, I assume from flexing bits during chatter. I had a substantial burr around the drilled holes that required a bit of deburring...which wasn't done as cleanly as I'd like. Now to give it a function test before breaking out the new Cerakote and airbrush kit!

 

[cozmogeek]

I haven't made any of these yet but that doesn't look bad to me!