From Manual to CNC - Sherlines

[mklotz]

Now...off to Home Depot to get the items needed to make the bases for the machines.
Initially I was going to mount the machines to my lab workbench but I didn't like the idea of drilling holes in the bench and it would set a terrible precedent if I needed to move the machines.
It is also true (as mentioned in the documentation) that mounting directly to the workbench will amplify motor noise and vibration.

With a machine on a base with rubber feet, I'll be able to move the machines around.
I'm limited to a 5' long workbench and this will allow me to move the machines around as I need them.
Hopefully they won't walk on their own.

I mounted my Unimat to a plywood base large enough that I can, when necessary, clamp it to the workbench with a bar clamp.  The plywood is also fitted with a steel plate in the area behind the lathe.  This gives me a footing for a magnetic base indicator holder.  If the steel plate is made thick enough (mine isn't) it could be drilled and tapped to hold other accessories (e.g. lights, drip oiler, etc.)

[crueby]

And give the wood base a good coat of tough porch paint or something so it does not soak up oil.

[zeeprogrammer]

Thanks all.

I'll work on the QCTP a little later.

I got the bases built and installed. I used a white shelf from Home Depot. It's covered in some kind of plastic so I don't know if painting is needed at this point.
They're a huge improvement in stability and noise but I notice the mill vibrates a bit. I don't know if that will be a problem.
(Be sure to drill from the top side. The board tears a bit when the drill bit gets through.)

Went through Hugh's thread. Lots of neat ideas there.

Thanks Marv. I like the idea of putting a plate behind the lathe. That's another to-do.

Concentrating on the lathe for now...

Reviewing all the various adjustments (backlash, etc.) and alignments.
I should be able to cut some metal in a day or two. Probably just face and turn a bit of rod and try some drilling and parting.

[zeeprogrammer]

Overall things on the lathe seem to be nicely adjusted but I haven't checked the squareness of the headstock yet.

 

However, I'm having troubles with the cross slide (X axis).
The biggest problem is the handle (lead screw rather) moves significantly left/right. Even with the cross slide fairly well engaged.
See the attached pictures. (The insert is there for reference.)

A smaller issue is the brass round nut at the end of the lead screw that goes against the saddle. It's rotation is prevented by a 'knurled' similar round nut next to it.
See attached picture.
I can't get that round nut to seat against the saddle.

On top of that, the ring (at the handle) with the zero mark rotates slightly as I turn the handle.
And, I can't zero the dial. It won't budge. I don't have the same problem on the Y axis. Nice and tight and I can zero the dial.

[Flyboy Jim]

Thanks all.

I'll work on the QCTP a little later.

I got the bases built and installed. I used a white shelf from Home Depot. It's covered in some kind of plastic so I don't know if painting is needed at this point.
They're a huge improvement in stability and noise but I notice the mill vibrates a bit. I don't know if that will be a problem.
(Be sure to drill from the top side. The board tears a bit when the drill bit gets through.)

Went through Hugh's thread. Lots of neat ideas there.

Thanks Marv. I like the idea of putting a plate behind the lathe. That's another to-do.

Concentrating on the lathe for now...

Reviewing all the various adjustments (backlash, etc.) and alignments.
I should be able to cut some metal in a day or two. Probably just face and turn a bit of rod and try some drilling and parting.

That plastic covering is called Melamine. No further treatment needed. Masking tape can help tearout from drilling, as can using a brad point drill bit. I used another piece of shelving for a backstop for both the lathe and mill. I was then able to screw some holders, for accessories, to that.

Here's a link to a scribe that Clickspring made on his Sherline lathe: <a href="https://www.youtube.com/watch?v=o8Bd8G21Vv8" target="_blank">http://www.youtube.com/watch?v=o8Bd8G21Vv8</a> It was my first ever machining project. You didn't mention if you have your Compound yet, but it uses that as well.

Hugh has made some really neat accessories for the Sherline lathe and mills.

Jim

[crueby]

Zee - two things on the cross slide leadscrew.

The brass nuts underneath control the backlash on the threads. To adjust that, you loosen the screw on the knurled ring on the side, turn the one on the leadscrew, then tighten the screw again.

But First:
The handwheel is what keeps the whole table from sliding off the leadscrew, that is where your main problem is. If you turn the graduated dial on the handwheel (loosens/tightens with the thin knob on the end) so that you can see the setscrew underneath (is that way in your photo), you can fix this. move things so you have the gap between the bed and the handwheel. Loosen that setscrew, and push on the table so it is pushing the leadscrew towards the handwheel. At the same time, push the handwheel in to close the gap. Then tighten the setscrew again. When you rotate the handwheel, you will likely still see around four or five thou of turning (as shown on the dial) before the table moves - this is normal, and is about as good as it gets. If you are seeing 10 or more thou, then the handwheel needs to go in more. That setscrew will make a divot on the end of the leadscrew rod, so you may need to turn the handwheel to a new position if it slips back into its old spot every time.

Once that is adjusted, then you can see if the brass wheels underneath are needing adjustment. Also, make sure the gib is in far enough to give some resistance to movement.

On my mill, I made a replacement handwheel that has a way of taking up that slack, but if you are going to put the CNC handwheels/motor/leadscrew in, you wont need that, the CNC version has a preload nut that fixes this flaw in the Sherline design. For some reason they are very reluctant to change anything that Joe Martin designed, even if a simple change will improve things a lot. He did a wonderful job, but any design can be improved.

[zeeprogrammer]

Thanks Jim.
Thanks Chris. I'll try that out. I will likely have more questions as I didn't quite understand everything.

A few other questions...

1) The tailstock, when not locked down, wobbles quite a bit. Once locked it is very stable. Is that expected? Will it be aligned properly? (I haven't measured yet.)
2) On the mill, I can lock the Z axis. I'm still hunting for a way to lock the X and Y. Is there a way? I see a knob to the left of Y but I can't move it.
3) Same thing for the lathe. It's not clear to me how the axes get locked.

(I'll probably do some googling this evening...but you guys are easy.  )

In any case, I couldn't help myself and did some cutting.
See attached picture.
On the mill I flycut the top, center drilled and drilled a hole, and took a pass with an end-mill. I was impressed. (However I have no idea how the flycutting did as the surface is nearly smooth as glass and devoid of machine marks. (Again, I haven't checked squareness on anything yet.)
On the lathe I faced, turned, center drilled and drilled a hole, and parted. Again I was impressed. Best surface I've ever seen (in my shop).

I may be moving to CNC sooner than I'd thought.
First though I need to rearrange the shop. I want to figure out a way to have all my machines in the back of the shop, arranged in a way to minimize swarf everywhere. I'm trying to get a 4x8 table in hoped of building a small railroad (I have grandchildren! Yeah.)

[Hugh Currin]

Zee:

I don't think you want the brass round nut to seat against the frame. It is for backlash adjustment, you loosen the screw holding the meshing brass round to be able to turn the round nut. Once the backlash is taken out by rotating nut till "snug" tighten the screw to hold both in position. If the round nut were able to seat against the frame it would mean you're out of adjustment. See the Sherline directions.

A smaller issue is the brass round nut at the end of the lead screw that goes against the saddle. It's rotation is prevented by a 'knurled' similar round nut next to it.
See attached picture.
I can't get that round nut to seat against the saddle.

[crueby]

Hi Zee,

The tailstock wobbling when not locked down is normal, you would only use it locked down.

For the mill table, there is a knob on the left side under the table, that is the one that Jim and I both suggested the replacement for, the little stepped block. The knob they provide will slow movement, but not lock it. That one controls in/out movement. For left/right movement, there is a SHCS on the front right of the leadscrew, on a little rounded bump. That is the lock - tightening it will lock the left/right movement. Also can be snugged just a little to give more resistance like the gib does.

For the lathe, there is no lock for the carriage.

[crueby]

Zee:

I don't think you want the brass round nut to seat against the frame. It is for backlash adjustment, you loosen the screw holding the meshing brass round to be able to turn the round nut. Once the backlash is taken out by rotating nut till "snug" tighten the screw to hold both in position. If the round nut were able to seat against the frame it would mean you're out of adjustment. See the Sherline directions.

A smaller issue is the brass round nut at the end of the lead screw that goes against the saddle. It's rotation is prevented by a 'knurled' similar round nut next to it.
See attached picture.
I can't get that round nut to seat against the saddle.

Actually it should be against the frame - it has a stepped back that fits into the hole, and should be all the way in. Adjusting the handwheel should push it back in all the way.

[Hugh Currin]

Zee:

I'd suggest, for CNC, that you put the machines in enclosures. A simple box with folding plexi front cover. That does a good job of keep swarf inside, then a shop vac can take care of it. The only pain is cutting fluid if you have to open the doors to apply. The Sherlines are small enough the enclosures aren't gigantic, but would make them more clumsy to move around.

I'll soon be setting up my shop more permanently and plan to build enclosures for my Sherlines. I also want to make up small mist coolant systems for them. That will eliminate hand application of cutting fluid for the most part.

First though I need to rearrange the shop. I want to figure out a way to have all my machines in the back of the shop, arranged in a way to minimize swarf everywhere. I'm trying to get a 4x8 table in hoped of building a small railroad (I have grandchildren! Yeah.)

[Hugh Currin]

Crueby:

I'm wrong, and you're right. I though the nut was threaded into the frame but it's a slip fit on the outer OD. So its shoulder has to go up against the frame to work against the main nut and reduce backlash.

Thanks.

Actually it should be against the frame - it has a stepped back that fits into the hole, and should be all the way in. Adjusting the handwheel should push it back in all the way.

[crueby]

Crueby:

I'm wrong, and you're right. I though the nut was threaded into the frame but it's a slip fit on the outer OD. So its shoulder has to go up against the frame to work against the main nut and reduce backlash.

Thanks.

Actually it should be against the frame - it has a stepped back that fits into the hole, and should be all the way in. Adjusting the handwheel should push it back in all the way.

No problem - I only know since I had to replace the one on my lathe last year, finally wore it out!
 

[Flyboy Jim]

No problem - I only know since I had to replace the one on my lathe last year, finally wore it out!
 

I'm surprised you wore a piece out already Chris. You've hardly used your machines! 

Jim

[zeeprogrammer]

 

Haven't had time today to work on the machines (infant grandson wasn't interested in napping) but I had a chance to learn more about the stepper motors and the G540.
Crud.
The motors have 8 colored wires.
The motor can be wired as unipolar, bipolar serial, or bipolar parallel.
What wiring diagrams I can find...the wire colors don't match (not surprised).

Check me...

The choice would be between series and parallel.
In series there is more inductance and less current per phase.
In parallel there is less inductance and more current per phase (motors get hotter but higher speed is possible).
It's not clear to me which provides more torque at low or high speed. I'm thinking parallel.

I'm leaning towards serial. The current per phase is half that in parallel. What do you think?

Got some wire and wire protection ordered.
Also ordered an e-stop (which is probably rated way higher than needed but I want it to look like an e-stop and be latching).

Ah. Grandson has gone home to daughter. Now I can...no...I can't. It's after 5. Stinking Hoppie time.