New mill base for PM-728

[feral_cat]

I needed this machine to be higher. I also wanted to be able to move it around. 2x2 steel tube and leveling feet (not the oddball 1/2-12 ones it came with). Came out alright. Turns out drilling 1/2" in steel is about the max on this thing.

 

[ChazzC]

I needed this machine to be higher. I also wanted to be able to move it around. 2x2 steel tube and leveling feet (not the oddball 1/2-12 ones it came with). Came out alright. Turns out drilling 1/2" in steel is about the max on this thing.

View attachment 418975

I’d be concerned with the tube flexing, but otherwise: nice.

You should be able to drill over an imch if you do it in multiple steps. Frank Hoose has a video drilling a 1” hole in 1/2” plate by going in 1/16” increments on SIEG mini mill.

Can also use annular cutters, which require less Hp.

 

[feral_cat]

Tube is 1/4 wall. I got the thickest I could for tapping the 1/2-13 threads. Seems pretty solid. I had set the width for the pallet jack, but then opted to just bolt on casters.

Yes, I did go over 1/2 with a step drill, but for one shot, I got the belt to squeal on 13.5mm drill. Specs for the machine say 3/4" max drill, that must be for AL.

 

[ChazzC]

Tube is 1/4 wall. I got the thickest I could for tapping the 1/2-13 threads. Seems pretty solid. I had set the width for the pallet jack, but then opted to just bolt on casters.

Yes, I did go over 1/2 with a step drill, but for one shot, I got the belt to squeal on 13.5mm drill. Specs for the machine say 3/4" max drill, that must be for AL.

Step drills are good for sheet metal and plastics, but not so much for 1/4" steel - they would require more Hp than a conventional drill. I was suggesting drilling in steps with separate drill bits. Here's Frank's video (it was a 3/4" hole in 1/2" steel, on a LMS 3990 mini mill (same as I have) and he was struggling):

Here is the other video that he refers to:

[edit] The PM728 is rated for 3/4" drilling vs. 1/2" for the LMS 3990, so if the belt is properly tensioned, you have the part tightly held and are using the right feed & speed 13..5mm should have been no problem with a conventional drill bit.

 

[feral_cat]

Step drills are good for sheet metal and plastics, but not so much for 1/4" steel - they would require more Hp than a conventional drill

It worked just fine. I just had to opne up the clearance holes for the feet to go through. Yes, you can upsize holes with larger drills, but they can get pulled into the hole if you're not careful