Bit of a windfall

[Benonymous]

A friend of mine who is a world class scrounger found this a couple of years ago and kept it.



It is an optical device used to reduce blueprints. It's a precision made device and as you can see, it has the potential to make a nice Y and Z axis. i posted another machine idea before so I might incorporate this hardware into my build rather than hang about waiting for good hardware to become available on eBay.

Do any of the members here think that this might be a servo?



This is definitely a stepper.



Decent lead screws and ballnuts..



And here's the potential Y/Z stripped out of the main assembly.



The other benefit with this is that the chassis is a big slab of 12mm alloy and there are a bunch of nicely machined brackets and fittings that can be repurposed.

The main carriage for the Z axis ran on another rail at the bottom. This comprised a square, ground rod and the carriage has a simple friction bearing and adjuster screw. This would be replaced with a linear rail and truck/s.

The Z has a stroke of nearly 300mm and the Y has about 500mm effective travel. I haven't checked the screws yet but they look to be about 5mm per turn or so

The only thing that puts me off a bit is the motors. I don't know if I want a mixture of servo's and steppers, so I may proceed with my plan to get the 3 servo kit from Ocean Controls and adapt them to this hardware.

[Benonymous]

I've done some measuring and the screws are imperial. The Y axis is 0.5" per turn and the Z is 0.2. Funnily enough, the rest of the machine is cut in metric. I was incorrect about the stroke of the Z axis, it's more like 170mm rather than 300.

I've measured the rest of the parts and I'll incorporate it into my design.

[Jay C]

Originally Posted by Benonymous Do any of the members here think that this might be a servo?

Measure the resistance between all the wires. Just from the looks of the wiring I'd say it was a stepper too.

Jay

[adamsj3]

Jay-

Turn the shaft of the unknown motor by hand. If it "cogs", you can be confident it's a stepper. If it doesn't, you might still have an "unknown" motor.

Good luck.

Jack Adams

[Benonymous]

Thanks for the replies chaps I'll take the motor off and do some tests. I Don't see an encoder on it so you might be right Jay.

I've turned the lead screw by hand a few times Jack and I didn't feel any cogging so maybe this motor was simply for positioning and didn't need to be precision driven. Who knows, I never saw the machine operating.

If the motors are standard NEMA mounts (looks like it to me) I might swap them for known motors that I can definitely interface to a driver/controller.

[Benonymous]

Just another thought. If I use the assembly the way it is, with the ballscrew on the top and another rail on the bottom of the Z axis sled, is this arrangement likely to rack? I notice with most hobby machines, the creators like to keep the drive central to the axis of the moving part.

I don't want to build a dud machine just to use up these parts.

[arizonavideo]

100% chance they are steppers. You would not direct drive a 5 TPI with a servo and no encoder.

The 6 wire big one may be a unipolar which will work with a bipolar driver but it will be a bit slower.

Nice screws too.

[Benonymous]

Thanks arizonavideo, I think the lack of encoders would be the strongest tip for steppers. i hadn't considered that the big motor might be unipolar however. i'm just getting up to speed on the tech details of all the hardware really . I'm in two minds whether to use all of this gear. The Z axis arrangement is quite useful but the bespoke construction will mean deviating from the relatively straightforward machine that I imagined building.

I'm starting to think that I should press on with my original plan and scratch build the machine I really want. There is still some useful hardware here and I may be able to use of parts of it.

My ideal table would be 1200x600 work area and this hardware won't encompass that.

[Benonymous]

The windfalls continue. My friend who scrounged the machine has also scrounged me some 20mm THK rail. I have two lengths of 20 x 2000! I'm not going to build a 2m long machine as I don't have room for it. The only problem with the rails was that they came with two totally shagged out trucks.

To remedy this situation I have bought a set of 20 x 680mm rails and four trucks from a vendor on eBay called FA Parts. Here's the package.



Two layers of foam and a plastic bag.



And the nice shiny parts, they hardly look used at all.



I don't have pictures of the 2m rails but the idea is to test these trucks on the 2m rails to see if they're OK and then order some additional trucks for them. I will use the 680mm rails for my Y axis. I'd like to have four trucks on everything and I'll probably use 20mm rail on X,Y and Z just to keep things straight.

I'm really happy with the service from FA Parts. They called me right after I paid for the rails to confirm the shipping details. Communications have been first rate and the freight was around two days from being dispatched. I just thought I'd give them some props on here because it's difficult to find good info on eBay vendors sometimes.

[sverstegen]

I too have had good experience with FA-Parts. I ordered some THK Linear bearings and rail, and an ISSOKU Ballscrew. They were sold as used but look and function as new. Both arrived well packaged approx 5 calendar days (from Korea to TX) after payment.

Good luck with your build- PM me if you come up with extras once you get your BOM nailed down.

[Benonymous]

No Worries sverstegen, I may have some round rail (unsupported) and a couple of motors spare the way I'm going.

[Benonymous]

Well looky what I got here!



A nice ground ballscrew, 25 x 1000mm with a 5mm per turn thread Effective stroke is around 900mm

The ballnut from hell!



Screw is in fine condition.



And what else has my mate scrounged up for me?



A couple of decent stepper motors. They are marked 3V, 1.8 ohm per phase. They are an RS Components part so when I get a moment I'll look them up.

Also this.



Which appears to be a unipole motor, no obvious steps when turned by hand.


Here's the 2.2m rails.



One was in really good condition but the other was quite rusty. A bit of elbow grease had it looking presentable. There is some minor pitting on the upper surface but the grooves for the balls all polished up clean.

I'm still short four 20mm trucks so I'll be on the hunt for those on e Bay.

I'm still not locked in to the dimensions of the machine. I don't really want to cut my lovely 2.2m rails but I don't want a machine on that scale first up. My feeling is to get a set of trucks and rails to suit the 900mm screw and use the 680mm rails I bought before to go with the Warner nut and rolled screw I got off the plans machine. Then I just need to sort out a Z axis maybe using the Warner nut and rolled screw from the plans machine again.

That would make it X-900 x Y-600 x Z-170. Pretty good for a first machine. I'll start a build log in the appropriate sub-board.