[BrendaEM]

Firstly, I want to thank Darla and Terry. I don't usually like the look of anything, anywhere, dedicated to anyone, but the heavy fact that remains is that I wouldn't have this stuff if someone hadn't died. I found Darla kind and generous, and while my friend and I never got the chance to meet Terry, in talking, we both decided that we would have liked to.

At otherwise, the neatest garage sales I've been to, I acquired a small x/y axis, as well as a z column.
This stuff was originally made in the late 80s for planer wafer inspection, so it's made to pretty fussy and strange standards.

Each axis is the same bolted together. The machine had just as much y travel as x, which appears to be about 150mm, which is small.

The ways are ball-bearing in cross-point separators.
The first thing that makes this strange is: the axis has no cast iron in it. It appears to be wire-EDM'ed out, and ground/milled from there.

Also strange is the circular thing in the sled portion is a reservoir for oil, which seeps down a cotton wick, which I will show in the post below.
You can see the seepage from the oil escaping the press-fit cap. The photo is before I cleaned it up. (Way ends are not shown.)

Attachment 292098

The pin showing on the lower of the sled is spring-loaded and contacts the limit switch. There are three, including a roller one for the center.

~

Looking at the end, the ways are 20mm x 20mm steel bar, which appears hardened. They are grooved for the bearings. (Unpictured) The ways are bolted down from the bottom, which is sub-optimial for adjusting as the lower axis may be hard to get to. There are adjusting screws coming in from the right to adjust the bearing crush. Otherwise, I like how simple the construction is. Usually in small mills, we have a heavy axis and light ways; here, we have a light axis, but very heavy ways that are bolted down low. The tall sides of the axis appear to be used only for axis rigidity, and for adjusting the ways.



The Axis, two ways, the sled and bearings weigh 19 pounds.

I took apart the axis, cleaned the bit of surface rust and applied WD40. Fortunately, the bearing groves and contact surfaces were fine, so it's only cosmetic. A nice cover system was included.

[BrendaEM]

This is the lead-nut assembly.

There is a 1mm pitch leadscrew, about 14mm in diameter.

There two large bronze nuts, with bolts and springs that apply preload.
Notice the oiling wick, which contacts the screw. The wick is fed from the tank in the pic above.

Where it gets strange is: they wanted to isolate the leadscrew runout from linear moton. In a fanatical way, there are ball-bearings between those 2 thin steel parts (one is broken), separated by a brass ball-retainer plate.
Small belleville washers and double nuts keep the preload on the bearings.

[BrendaEM]

This is how they handled the screw end.

They used an adjustable preload to take all of the end-play out of the screw. The adjuster is in the black endcap, which transmits the force to the screw via a single ball.
This force is stopped by the bearing, kept with an E-Clip (not pictured). The way-end is cap bolted to the axis.

The other end of the screw has smaller bearing race. I suspected they thought that a small race would be fine because there would be very little pressure against the sides of the screw, anyway.

[BrendaEM]

This is the column I got.

It originally had a crank system for raising a machine head. I going to take this out.
In the picture, I tried inverting the leadscrew, but there's no way to preload the nut.
Also, there is an aluminum part that grabs the leadnut slides which is good because it lets it slide forward/backward, but there's no way to preload the vertical motion, and it's only aluminum.

So, sadly, I will have to replace this with a ballscrew assembly.

...But, it's not all bad, as the column rides on roller bearings, and the column itself is solid except for the space for the lead screw. Yes, there are no other hollows in it. The back is flat. It weighs 55 pounds.

Attachment 292108

[BrendaEM]

This is the leadnut assembly.

In the mid-right (no, below the quarter : ) there is the block that mounts the nut to the sled. It has two bearings which ride in the grooves. These bearings are separated by the brass plate (bottom).

On the right-lower, this is the plate that mates to the one with the bearings, and just above it there is the plate I made to replace the broken one.

Looking at the end of the leadnut, this system keeps the up/down left/right motion from affecting the sled. All of this to prevent deflection. The system would correct a bent screw of perhaps .5mm.

My replacement part is not perfect, but it was made only with a drill-press, dremel, files, stones, and a belt/disk sander.
The part is made from O1 tool steel. I still need to harden it.

In back there are the bronze nuts, which seem good sized for a small machine. <-- Not my link.

Attachment 292104

[BrendaEM]

So, I am thinking that I might make a micro mill from this stuff. For now, I am going keep the leadscrews, as I am living on a poverty-line fixed income. The screws will be worn out in a year or two, but should be pretty accurate until then.

If it's 1mm pitch / 200 steps gives 0.005mm. That divided by 16x microstepping gives 0.0003125mm, which seems impossible...
But if this stuff could hold perhaps 10 pounds of milling pressure at .01mm I will be pleased, and it it will do .001mm, I will laugh.

I think I am going to take the existing screw parts out and get a ~400mm ballscrew from ebay. Obviously, I want to keep the bearing system, but I need to devise a way to mount them.

[BrendaEM]

This is how I honed the bearing groove.

Before I got to this point, I used a dremel tool and a cut-off wheel to make the slots. I used the grinding bit to make the bevels, and then filed it a bit.

Here shown in the photo, I used a knife sharpening stone to grind it. I used an expensive scrap of derin for a guide, which helped a lot. Yes, it's crooked in the picture.

I used a feeler gauge to check the depth of the groove, kind of like that, but level.



My neighbor gave me these rubber-coated fabric gloves, which work great for this kind of thing, because when you are doing this, your fingertips are always touching the edges and corners of the part.

[BrendaEM]

I finished the part I was working on. I made a little tent from cut up floor tile, and used a propane torch to heat up the part before quenching it in oil.
My first attempts weren't good, as I didn't have enough oil to take the heat away. I added more oil. Though, when I quenched it, the flames were pretty frisky.

In testing, a file can still put light scratches on it. I would try to harden it again using a greater amount of oil, but I am almost out of propane.

The part is baking in the toaster oven, at 400F for 2 hours. No basting. No pop-up timer. I refuse to run my roomate's toaster oven at 100%.
I also might take it out of the oven a bit early because it wasn't a perfect quench, thinking(?) that if it isn't fully hard, it doesn't need a full temper.



The surface of the metal was shiny, but pretty black when I pulled it from the oil.
I had never seen oil so thin as what ran off of the part, while it still had a bit of residual heat.

[BrendaEM]

Let's see now. Umm. Deep breaths. I feel like a monkey messing with the monolith, working on this stuff. This was the finest German engineering there was back then.

Attachment 292198

The tray on the right is mostly for the thrust system and leadscrew support.
The tray in the center has parts and springs for the preload...um, system.
In the lower right, you can see the broken part, that I made another one of. I found bearing dents in it's mate, so it looks like this machine was dropped which broke the part.

On the lower but not bottom right, there are threaded pins which have an O-ring on them. A what?! Well, perhaps they found that the rods vibrated or something. Well, this was a microscope.
It wasn't evident until I looked at this picture that the studs thread into the diagonal holes in the leadnut as seen next to the scribe. Okay, I think I get it now.

In the center we can see the thick steel block that cross-bolts to the bottom axis sled. They have bearing groves in them too.

On top center, miraculously, all 8 steel balls are there.

On the top right, you can just make out that some of the thin diagonal bearing plates bolt to the leadscrew.

In the top-left, I intentionally placed the tube ParkTool polyurea grease. Polyurea grease is supposed to be the best, and the ParkTool brand can be found at most bike shops, and costs around $6 with tax. This stuff is made from isocynates, almost like the kind that killed 6,000 people, and hurt 500,000 more in India. I think I won't waste it or use it on anything that doesn't need this kind of lubrication.

[BrendaEM]

Something like that, but with grease and ball bearings.

Attachment 292200

From right to left.
Block with bearing groove. Mounts to sled.
Brass spacer.
Bearing plate grooved on both sides.
Bearing plate that mounts to leadnut.
Leadnut with (laughs) oiling wick hole.
Studs.
Leadnut.
Preload spring.
(More concrete : )

Nuts, spacers and washers go on the ends of the rods, apparently.

I have to count up all the little belleville washers. I should think that the belleville washers go on the side with bearings, which leaves flat washers for the preload side.
I should figure out how much preload I want, and also figure out how strong the belleville washers are.
I want to test the springs to see if they are stiff enough.

[BrendaEM]

I've got one of the axi back together. At first I put it back together as wrong as I possibly could. All the limit switch provision were on the wrong side.
On the bearings, you can see the blue polyurea grease on the bearings.



Oddly, the ways seem to be made of tool steel, and the rest mild. Online, 6 feet pf 20mm x 20mm tool steel would have been expensive.
I need to put the limit switches in, and come up with a stepper mount.

[BrendaEM]

This is the center switch. It's mounted with grubscrews that fix it anywhere along the groove.



The switch is on a pivot lever on it on has a mechanical disadvantage, in that the threshold of activation is made smaller by making action is more like a catapult and less like a equal teeter-totter. There is a ball bearing race on the end.

(On the lower left, you can see their needlessly expensive lathe-turned screw, holding in the spring loaded limit switch pusher. This stuff must have cost a lot of money when it was new.)

[BrendaEM]

Captain's Log: Stardate 9-20-2015: Still no posts but mine. Wondering if naming the thread with prefix "Build Thread-" would have helped. Crew moral is down.

[LeeWay]

But Capt'n, I just started readin an I'm givin it all she's got.
Looking good so far. I have seen that type of way before. Typically on expensive drawer slides and placement machines where light duty is needed.
Now I do have a similar setup, but more heavy duty on the Z axis of my old home made mill. It simply has a row of balls on each side and one side is adjustable to preload. It was used when I bought it, but it was a complete axis. All cast iron.

I'll keep following along. I suspect that is what many are enjoying doing so far.

[BrendaEM]

Thank you for posting. I was getting a little worried.

Yes, the machine was made for light duty, and not really milling. Though, whomever made it seemed to spare no expense in making it accurate, so I am thinking that this might be good for making small fine parts.

Yes, your mill axis does look strong. Are the dark cylindrical units at the end of the screws, bearing retainers?

But Capt'n, I just started readin an I'm givin it all she's got.
Looking good so far. I have seen that type of way before. Typically on expensive drawer slides and placement machines where light duty is needed.
Now I do have a similar setup, but more heavy duty on the Z axis of my old home made mill. It simply has a row of balls on each side and one side is adjustable to preload. It was used when I bought it, but it was a complete axis. All cast iron.

I'll keep following along. I suspect that is what many are enjoying doing so far.

[LeeWay]

Right. Those are all ground ball screws with double bearings in each end mount.

[BrendaEM]

The machine originally came with anti-backlash ball-bearing 4:1 planetary gear drives, as shown in top right. Unfortunately, the ring gear (unshown) was a sacrificial nylon part. While the remainder looks like a miniature little Rhohoff hub, I can't use it.

The machine originally had Superior Electric 100in/oz steppers, oddly with optical feedback. Given that this is a budget project, I am going to test them and try to use them. They have 6-wire single-phase wiring, but can be wired for two-phase by ignoring the center tap.

I got some couplers, including the little black aluminum one, which should be good to do beginner mistakes with. Above that and near the green handle there is a stronger pivot one. The brass one next to it looks like it has done enough.

Between the black coupler and axis, there is a delrin block that was part of the original motor mount. If I drill and tap that block, I can bolt the block to the axis, and wallah!

I am cautiously optimistic. I am going to test the motors with an Arduino and a stepper driver.

Attachment 292968

[Fastest1]

Leeway isn't the only person watching.
Just observing as much as anything. Please keep up the activity. It increases our morale.

[BrendaEM]

Leeway isn't the only person watching.
Just observing as much as anything. Please keep up the activity. It increases our morale.

Thank you : )

[BrendaEM]

Drat! I lost one of the thrust ball bearings. It's a plain 6mm ball. I ordered some from Amazon.

~

Yesterday, I had a bit of surprise and minor disappointment, as I found out that the z-column isn't cast-iron after all, but billet aluminum. Well, for light milling it might still be okay. On the positive, I don't think it will bend because very little metal was removed from the column. The column has beefy roller bearings in linear rails, so the column is not going to wear except for the bottom surface. I think I am going to make an steel plate that bolts to the bottom that accepts bolts. In that way, the bottom of the column will not appreciably wear from tramming. I am still taken back that there perhaps $350 worth of tool steel in the ways, and perhaps $200 for the billet of aluminum for the column. Still, cast iron probably would have been better, but this is what I have to work with. The leadscrew has to go.



~

Last night, I bought a tap and drill bit combo to drill out the delrin blocks.
I am going to tap the motor mount blocks out tonight, and come up with a stepper sketch to test and move the axis.

The thing I don't understand is: the Superior Electric motors are only rated for like 5 volts @ 1-1/2 amps, but then I see tables for use with 24-volt systems. That does not seem to make sense. I often see this on ebay packages with motors with much greater voltage supplies than the steppers were spec'ed for. The stated voltage seems low for a 100oz/in motor. I've ran NEMA 17s with 12 volts; while they got warm, they survived. So for now, I am going to test them for 5 volts, and see what they can do.

I have a few Pololu/Allegro stepper breakout boards and an Arduino or two on hand, so for now I am going to make a hardware setup and rewrite a motor test sketch. I have a box of DB-9 related plugs, which should take as much amperage as the motors would tolerate, and so in keeping this a budget project, I am likely going with this stuff. I have a takeout computer power supply, as well as some others kicking around. So I'll try to get something going.

I am looking forward to making the motor axis test : )