Mill table dual stop

[petertha]

I have a lot internal pocket milling work on the horizon & that can be very tedious chore without some kind of stop to limit travel as you work your way down the material end milling (as opposed to watching dials and/or DRO position at each end of every pass). I made a similar system for my old RF-45 mill & it worked out pretty good. The basic idea is you set the table to desired left position, set the left stop. Then do the same for right. Now when milling you can just traverse the table back & forth until it contacts the stops on either side.

My 935 mill has different dimensions so about all I could use was the concept & materials on hand. I have a power feed on the X so I temporarily removed the limit stop switch, wrapped its cord up neatly & just strapped it to the motor unit so its out of the way. Yes, the electric limit switches work pretty reliably as an e-stop, but I find power feeding short lengths is more of a hassle than its worth. The spring limit bumpers just slide out of the Tee slot along the front of the table. The mill base was already drilled & tapped 5/16 for the center limit switch so I decided to make use of those holes.

 

[petertha]

Here are the components. A chunky center stop plate (1/2" steel...cause that's all I had in 3" width), the left & right bumper plates (3/16 steel x 2" high x 2.5" long) and elongated tee nuts to accept them (steel). I made the bumper plates tall to maximize the contact area along the front of the table.

The system cant take a hard traversing hit without losing a couple thou, but I found by just tightening them up reasonably I can easily get half thou repeatability multiple times by just walking the table in slow & kissing the center plate. The three (10-24) cap screws is a bit overkill but A) it spreads the the load & clamps the plate securely just using an hex key on the cap screws B) I make use of this hole layout to make the round-over profile in subsequent step.

 

[petertha]

Here I'm just using a scrap of aluminum as a turning fixture. The nose radius of the bumper plate can be anything, it just makes tangent contact to the center plate. So by using 2 of the holes & sandwiching the plates together, quick work is made of the curve profile for both parts simultaneously. I hate interrupted cutting because hot chips have a way of finding my head, so I bandsawed most of it away beforehand.

 

[petertha]

Here it is installed. I wish I could think of something similar for the cross axis but its a bit more cumbersome. If you come across any ideas let me know.

 

[brino]

Good idea.
Very well executed!

Thanks for sharing it.
-brino