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Jo_Jo,

This transistor will work, if you make sure your power supply voltage is 5V. At 3.3V the Gate-source threshold voltage (max 3.5V) might be higher than the drive signal from the...

I think its correct in the datasheet. It says "to produce zero current in a motor the ref voltage should be pulled above 2V, turning off all drivers"

Q1 is a PMOST, with the Source connected to...

Guys,

I just noticed I had swapped the Q en Q_not outputs in the diagram... I redrew this from a PDF file. I now have replaced the schematic diagram in my initial post to be sure there is no false...

One is Power-ground and the other is Signal-ground. It has to do with noise that occurs on the ground line (especially in the power ground) if you have long wires to the supply. This noise could...

Hmm, I think this circuit comes from a internet tutorial : "jones on stepper motors" or something like that.. Just do a google search. I believe there was also a PCB layout in this tutorial.

John

Hi,

A basic circuit to this is uses 2 flipflops (74hc74) and 2 exclusive OR gates (74hc86).
See pic.

John

Hi Jo_Jo

1) If you disable the sync input the motors will make a slight hissing noise,
but the performance will be better. So it is best make sync input low.

2) Yes, the supply voltage for...

Yes, you can drive them at 2A. This will give you roughly 2/3 of the nominal torque. If you are going to drive them at 2-3A you need to wire the coils in series. The L298 can do 4A if you connect...

The 270 oz steppers from automation direct have a max current draw of 2.8A. I run them at 2A with a xylotex board.

BUT:

They need to be geared to drive a large pinion. I think the largest...

Watch out santiniuk! Its all patented :D

mvaughn,

It is aluminium extrusion I found on the local scrap yard. Think its some kind of window channel. There was a rubber strip in the nut where...

45 kg is not extremely heavy. The gantry on my router weighs about the same and I use 270 oz steppers 1:3 geared on a 3/4 inch diametre pinion. It accelerates to 500ipm within 2 inch of travel. If...

The beast is alive.. After a few weeks of intensive use I'm happy to see that the pinion on allthread drive still holds up fine. No detectable wear or backlash.

If someone cares to see a crappy...

More pics.. It is almost time to run a shovel through my garage to make some space for this baby.

Wow, you have found some nice stuff at ebay. This is going to be one slick router. would it be difficult to convert the Yaxis to rack and pinion instead of upgrading the belt?

John

I guess its fairly reliable. I've tried it for a few known steppers and got within 80% or so of the manufacturers specified torque. On the other hand I think they sometimes are a bit "optimistic" in...

You can mount a lever of a certain length to the shaft. Clamp the stepper to your workbench and very slowly run it while the end of the lever presses on a kitchen scale. When it stalls you have your...

Also for rack & pinion you can use a toothed belt reduction. Cheap and no backlash.
A strong stepper can even direct drive a small pinion on rack. In that case microstepping can be used to increase...

Thanks Bloy, I'm not disappointed so far... Maybe I'll rebuild my old router with a similar approach. I have an idea for a drive module that can be simply mounted to the gantry base. See pics. The...

Thanks Javadog, its been a while since I posted. Some progress to report however. I've tried out the pinion on allthread-rack idea. Can always upgrade to $$ racks but for now it seems to work great....

Problem solved. I simply routed a groove in both panels to give the belt more clearance. Luckily the rims on the small pulley keep the belt in place on the large pulley.

I have a crazy linear...

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Thanks guys, I'm going to buy them.

Mac, do you run them at 2.5A setting or a bit "on the safe side", like 2.2A?

John

I've seen quite a few people here use the 276OZ-IN steppers available from xylotex, hobbycnc, automationdirect and so on. I've added a pic to show which type I mean. They are 2.8A/phase. Xylotex...

Finally got around to route the gantry side panels. I'm pleased with the fit, the shafts can be slid through the stacked panels with some force and will stay put. I'll probably need to strengthen the...

Yes, that can be done. You need to place a resistor (say 22k/0.5W)) in parallel to each capacitor to define the DC voltage in the middle. Without these resistors the mid voltage would be floating and...

Ok, the Z-axis is finished. Its one half of a small XY table. The other half sits happily on my current router ;). For this one I made a few trespa panels to extend the stroke to 3.5". Also I got...

Here's mine. Reducing the size to below 100k lost a lot of the sharpness and light. How do you do this?

John

I think you will have plenty thrust. I run my current router at 1:1 gear ratio on a 4mm pitch leadscrew. 8tpi is rougly 3mm pitch. My steppers are weaker than yours, so you shouldn't have a problem....

Lee,
You are making great progress! Building a lot faster than I am.. At this rate you'll be done next month ;)
Out of curiosity: I noticed your gantry base consists of two seperate L-angles....

Yes, actually there is one guy in the Netherlands doing just that: http://www.2004all.com/paket.jpg
I'll just make some parts of it. The gantry side panels are 72mm thick. Routing them from Trespa...