The Little Tank Mini Mill

Little Tank Mini Mill – Day 3

Whole lotta things got done in the past few days! I haven’t had the time to update this blog what with July 4th and everything happening at the same time, so I’ll just pretend I got all this done in a day, making this a combined 3 days of work in one post. Pictures…pictures everywhere!

I started out milling in those side plates to keep my milling machine as true as possible.

A little oversize to leave room for the bottom radius.

Just to get a sense of scale (And, because I couldn’t help myself) I put the blocks under the main slab.

Looks pretty good to me!

Next step was adjusting the milling machine to cut at a 45 degree angle. Because the plate was so big, and the way I had designed the cut, this was the only way to achieve the side profile that I was after. It was a pain in the butt, but (eventually) I got it to work exactly how I wanted it to!

Check out this video to see the cutting in action:

Ooooooh, yeah. Perfect.

(Another little glimpse of it put together, because I can’t help myself )

Next I decided it was a good time to throw on the smaller chamfers around the edges, so I marked up my piece, threw the slab back in the mill (After repositioning the head), and got to work.

Here’s a little trick for those of you with a face mill like this…Those inserts are held with a 45 degree angle on each edge, so if you want to throw a chamfer on something, this method will cut what you’re looking for very easily!

Now it was time to pop in those counterbored holes for the mounting screws. I set a stop and picked up my far left edge.

After that, I positioned my self over the locations of the three holes and popped in a center drill to align my holes exactly where they should be. I did this on both sides, just turning the plate around and pushing it against the stop to mirror the features on the other side.

My slab did NOT want to be cut with a drill though (cheap drills!), so I first had to punch out a hole with an endmill to make it a bit easier for the drill to go through. The endmill cut like butter! Who would’ve though cast iron would be so weird?

Next step was putting in the countersinks. I found an endmill that was right next to the size I needed and cut out the majority of the hole for the head of the bolt to sit in. I had to run over them again with a boring bar to open them up a little bit though, but in the end, it turned out great.

Here’s a video of me boring out the holes. It’s a huge cut I know, but I’m impatient and they were just clearance holes.

The top plate is 99.9% done! The only thing left to do is to radius a few edges later on, and finish it with a black coating.

On to the side blocks!

Same approach here, set my stop, spot drill my holes…

Drill em’…

And tap em’…

(I love my makerspace)

And finally…

My ritual test fit!

Lookin good! Now for the detailed part.

I laid out all the features each block would have, where, and on what side. This is extremely helping in making sure that everything is cut right. Especially since these parts are so similar, and I hate starting parts over, they needed to be perfect right from the start. In these pictures I’m using an acu-rite mill.

I got a little sidetracked while I was machining, but here you can see I’ve drilled and tapped the mounting holes, as well as milled out the spot for the floating end of the ballscrew mount. I also drilled and milled out the two chambers for the guiding rods to sit in.

Next up was that bolt hole pattern around each mounting point for my bellows mounting flanges to fit onto. This was easier than it looked because my machine had this function built into it already. God I love technology.

Instead of spotting each hole, I just held the drill with a little tiny bit sticking out so it wouldn’t deflect. It worked out great!

Tapping these puppies was actually pretty darn easy! I was worried my cheap little taps wouldn’t be able to handle it.

Now that the front was done, I flipped the block over and started to put in the counterbores for the guiding rod mounting screws to sit in.


(After cleaning and deburring it of course)

Now it was time for…yup, you guessed it…test fit!

I have a problem ok??

Here it is with the rubber mounts being test fitted in the mounting holes. My plan is for the guiding rod to be pulled into these and fit very snugly, thus reducing vibrations. That’s my plan anyway.

Block two was basically the same process, with a few changes. Here it is laid out so I don’t mess it up. Notice the mounting holes are already drilled and tapped. I did both blocks in the same setup so I wouldn’t have to reposition the machine twice for one operation.

I started with the counterbore for the mounting screw this time. Not having access to the Acu-Rite, I had to use a boring bar to make the right sized holes. Not too difficult, but just a pain in the butt. Here you can see I’ve already drilled my through hole and just finished my bore.

I kept everything in the same position and just flipped my block and pushed it against the stop. Easy peasy.

I cut out my guide rod chambers like before, except I had to use a boring bar this time.

Now for the ballscrew mount! It’s a pretty big hole with three different sizes and depths of counterbore, so I busted through it with a 1/2″ endmill, bored out the final through hole size, and then plunged down with this 1″ endmill to clear out material for the next step!

I ain’t messin around!

I’ll save you the hassle of having to watch me bore these each out, but here you can see them all finished and shiny!

After that it was drill, drill, drill. Tap, tap, tap. Only this time, I had a manual machine, so I had to manually position myself over each of the twelve holes, twice, while dealing with .060’+ of backlash in each handle. Talk about poop.

Here it is all finished, and ready to become part of the machine!

Drumroll please…


I threw everything together and even popped my guiding rods in their mounting holes

(They’re just floating in there right now, but it gets super tight!)

Everything is looking great so far! I can’t wait to see what it looks like when I get even further!

Like usual, more pictures, entries & updates to come!

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