An Electronic Lead Screw controller using a Teensy 4.1

Not really. But I have a piece of steel. Acquired it long ago. Didn't have a chunk of aluminum that size. Didn't want to buy the aluminum if I had something that would work. So it's steel. It's just some A36, so don't feel bad about using it. It doesn't machine like aluminum ;) but it will turn out ok. If at all possible, I'm trying to use the materials that I have on hand.
 
While setting things up found a minor error in my drawing. The right side slots were inadvertently offset a mm. Fixed that, and altered the slot width. Had set it up as 6.2mm wide. I don't have a 3/16 end mill with that LOC. So changed it to 1/4". Bumped the revision of the drawing to "A".

Won't be a pretty slot since I can't clean it up, but it allows me to use the tooling that I have. I will still use an M6 to fasten to the lathe. Want to keep everything on the lathe the same kind of hardware, i.e. metric.

Edit:

Ran into another gotcha. Ran out of travel in the Y axis. My vise hits the bellows bracket. I only need 5mm more travel to do this job. I have run into this before. A possible solution is to get a thinner bellows or make a window shade roll up. (The bellows is 40mm deep, I think one can get a 15mm version.) Think I will try to get the window shade thing to work. I had run into a problem with it a while back and put it down. Of course I forgot about it. And now it has bit me, again. The issue with the roller was the roller spring was expanding and hitting the ID of the PVC pipe I used. This causes enough friction that the device won't retract. Rollers use a torsion spring. Maybe I can bore out that section where the spring is. Think I can relieve the inside bore by 2mm in diameter which might free up the spring. Kind of hard to do this as the reach is 4", but it is PVC.

In the meantime, I redid the drawing yet again. Put the datum in the back left corner. If I do that, I can reach all the machinable sections without hitting the column. Which is enough to get this job done. I will have to remember this for future drawings.

Kind of weird to hit the stops with a piece that is only 4"x5", but that's how it works on these little mills with a vise. Could bolt it to the table, that would work as well. Or turn the vise around... Not sure why I didn't think of any of these things while I was in the shop.
 
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Some progress was made, although I don't know how. My morning was terribly disorganized. Got the slots done, although I broke a stubby drill. Never done that before. They came out OK despite that. Also drilled through the steel plate with an 1.25" hole saw. Like the last time, the hole seems to be off slightly. Think the arbor lets the hole saw wander. Fortunately, I was planning to bore it afterwards, so it doesn't matter. You can see the plug in the hole, it wouldn't come out, and I had to remove the piece from the vise to retrieve it. Couldn't bore the hole with the plug in the way.
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Surprisingly, my pulleys were delivered for the stepper and the lead screw. Also received the timing belt for the encoder. Didn't know they were here, but I got a message they had been delivered. Sure enough, they were at the front door.

The pulley fits the stepper just great. The set screws that are supplied leave a lot to be desired, they are M5 and 5mm long. They gave me a bag of them, maybe 20. Probably order some set screws in a reasonable size like 10-12 mm long. These set screws just want to pop out of your fingers and roll away. One of them did!
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Next is boring out the hole in the plate to 38.2 mm to fit the boss on the stepper motor.
 
And big hole is done. If I ever have to redo this plate, I'm going to buy some aluminum. That took a while. Lots of little hard bits in the steel. After the hole was trued (the saw is wacky, I tell you!) I decided to only bore down to where the pocket started and some extra. Saved some effort in this crummy material.
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And then a fit check for the stepper motor. The motor boss drops right in, not too sloppy. Happy with that.
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While everything is in this set up (with the motor removed!) I will drill and tap holes for M5 screws. They are at 50mm separation in x and y about the motor shaft axis. The weight of the motor is being held by these threads, which is one of my reasons for deciding to use a steel plate rather than aluminum. Assuming success, the next step will be to flip the plate and mill out the motor pocket. Finally the cable slot will be put in.

Just thought of something. Since I am going to flip the part, I should use the same datum as the top side. That means the datum will shift from the back left hand side to the back right hand side. Think I ought to edit the drawing on that (view) side to reflect that. Don't want some odd error to propagate through and mess up the plate due to any assymetries in the part.
 
I tried one of those with plastic and didn't have much luck getting the plug out of the bit.

Sometimes it is worth getting material more suited to the job than making do with what is on hand. :)
 
You have to use the proper arbor. Mine is R8 and it is spring loaded, when you have to proper pin installed, it automatically kicks the plug out of the bit. Steel, aluminum, plastic works for all.
 
The one I purchased came with arbor and has a drill bit and ejection spring in the center. The PVC plug did not come out and getting it out was time consuming and ended up damaging the spring. Perhaps it wasn't a good one, but it wasn't cheap. It's still in the drawer, perhaps sometime I'll look into it again. Apologies for the side-track.
 
Annular cutters don't use a drill bit like a regular hole saw. They are intended for a rigid setup like a magnetic drill or mill.
 
xr650rRider said:
That hole saw is ok when you don't own a mill. You ever discover annular cutters, you'll be like Adam Savage.

Adam Savage favorite tool.
Click to expand...
Hmm, I did buy an annular cutter for something, don't remember where it is or what it's size was. I should look for it. It was relatively cheap especially considering how terrible the hole saw is. Haven't used it yet. I should check that out.
 
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