Hello all,

This is my first (nervous?) post to this wonderful group.

Like most I suspect, I have been silently lurking here for some months before posting.

In this time I have bought and dismantled about 12 old printers(!!), purchased some separate stepper motors. and acquired quite few other parts.

I am now at the point where I need some input before I can continue.

The attached photos show the main ‘chassis’ assembly from an old Fujitsu dot matrix printer.

My most crucial decision is whether or not I can use this printer assembly as my (moving) gantry (= Y-Axis).

I would then make a simple Z-Axis assembly to take a Dremel size spindle (or the end of a flexible drive for a Dremel type tool).

I know I am just a newbie, but this assembly just looks so much like a CNC gantry (that somebody hid inside a printer) that I need to know whether it may provide a shortcut to building my first machine.

I have tried searching ‘the zone’ but I didn’t find any posts regarding a similar set up.

If the answer is yes, my intention is to build a machine which will then be used to fabricate the parts to make a ‘Joe’s 2006’ machine.

Details of the Assembly
The print head base is die cast metal and slides on two unsupported rails. The maximum travel is about 394mm.

The lower rail is solid, measures 20.5mm in diameter and spans 480mm. It appears to have mountings which allow adjustment of the alignment of the rail in relation to the upper (fixed mountings) rail.

The print head base has bronze bushes allowing the base to slide on the rail.

The top rail is also solid, measures 14.5mm in diameter and spans 463mm. The connection between the print head base and the top rail was a plastic bush with an integral (and now broken!) clip to connect it to the base. My intention here would be to devise a way to mount 2 (or more) skate bearings on the print head to keep it from rotating around the bottom rail.

The print head base is moved by a toothed belt which is driven directly (no gearing) by a Step-Syn stepper motor.

I need to know if this set up has any hope of being suitable or if it needs a radical ‘re-gearing’.

From my measurements;
- the teeth on the belt are approximately 2.8mm (50 teeth measure 141mm)
- the cog on the motor has 20 teeth
- the motor has 1.8 degree steps = 200 steps per revolution
There I calculate the full-step distance to be –
20/200*2.8 = 0.28mm
I read (somewhere here) that you should not use micro-stepping to increase accuracy, but I don’t remember why.

If I ran my set up using quarter steps (as I think is recommended for the HobbyCNC board that I will be using) I assume that each quarter step would be 0.28/4 = 0.07mm.

The motor is a NEMA 23 size – and it is yet another motor that is impossible (it seems) to find specifications for. The label shows-

Step-Syn
STEPPING MOTOR
TYPE 103-743-0241
1.6 OHM
1.8 DEG/STEP
D90L-1005-0170
LOT NO.08126
MADE IN JAPAN
6037684-2
SANYO DENKI CO., LTD.

Having read lots of posts regarding identification of steppers, this one is probably about 100 oz-in.

It wouldn’t be too hard to replace with another NEMA 23, but in the interests of making things easy, I would like to try this motor first.

Quite a long-winded post for a newbie I guess – but looking forward to any input.

-Ian

Such a great idea - Have not seen it on the forum - you may be able to remove the rails and print head unit for your jrgo ,rather than trying to make it fit to something else.If you can get hold of one of those old logabax printers wide carriage variety you will have some more motors and a good length of rails for your x axis .I suppose any old dmp printer would be a cheaper source for the rails. Why did I not thing of this - I am a computer engineer by trade doh!

That is a good idea.

If you are mostly going to use it to build parts for the "real" machine, or at least machine # 2, you might even get away with a "manual" Z axis. That way you can fairly rigidly and simply mount your dremel or flex extension to the Z location and just hand screw it down every once in a while to gain depth.

Most of the cutting work to build a router is really 2 - 2.5 D anyway, with some drilled holes.

Welcome aboard!
For sure - if its big enough for your first machine!
After all - when it was a printer that was the Y Axis!
As for the dremel, you might use the flex extension to keep the weights down on your axis to something closer to the old printheads!

With all those printers on hand - you ought to be able to make several (mini) machines.
:cheers: and best of luck - Jim

Just wanted to share some of the possibilities you've got!

Heres a couple of pics to show a few you could consider - use for what you like.

The first is a table top I was building but ditched because I didn't like the MDF! BUT the X AXIS was built from 2 sets of printer rails. They were cut then mounted to make a sliding X AXIS (table). I picked up a ball screw to drive that table. The stepper would be driving it directly.

The next CAD(s) are plans I have been working to make a sticker/vinyl cutter using all printer bits. I have considered making the X AXIS interchangeable between the 2 concepts - so I'd have a small 3 axis router OR a vinyl cutter by swapping out the Base/Platen. On the Z AXIS I plan on using a solenoid to drive the cutters down into position. For this the X AXIS is belt driven to the tracked feed and pinch rollers. The Y AXIS is belt driven too.

:cheers: Jim

Oh Yeah - if the Z looks a little funny - its the motor and drive from a 5 1/4 floppy drive. Another source for parts for mini-cnc!

:wave:

Hi again everyone and thank you very much for your replies so far.

At this stage I am encouraged that my 'idea' will work - but I would like some input on the stepper motor and the gearing of what will be the Y-axis.

Stepper Motor
I need to estimate the specifications of the stepper motor to set the maximum output current from the HobbyCNC Pro driver board.

The only known spec I have for it (as detailed in my post) is the coil resistance of 1.6 Ohms.

Would it be safe to use the specs for a stepper motor that has resistance of (or close to) 1.6 Ohms and has the same body size and is about the same age?

Drive/Gearing of Y-axis
Is a resolution of 0.28mm (0.07mm if quarter steps are used) within normal specs?

Will this simple toothed drive belt arrangement be rigid enough or will it have enough 'give' to allow excessive vibration?

Thanks again - I eagerly await the next message!!
Hopefully this will turn into a build log!