I probably will put a jog option on it, but I feel I need to be able to move by hand for somethings where I need to 'feel' my way into a piece and back off if things look like they are going west.

One thing which confuses me is that the the motor referenced above claims 4.2A and 2.96V. Why, therefore, am I considering a 24V power supply?

Iain

Hi, all.

Prompted by Bazyle's post, I thought I'd tell you where I'm up to with this.

This is what I plan to build

I'll replace the Y axis handle with a timing pulley, which will have a new handle bolted to it. I'm going to lose the graduations I think, but I've had news that my DRO kit may not be far off – and there's still the right hand handle.

The timing belt (not shown) connects to a timing pulley held on a bearing. On the outside (left hand side) there is a 3 fingered dog clutch (three clawed?). The motor has a 3mm keyway with the other half of the dog clutch on.To engage I slide it forward and tighten a lock screw. To disengage move it back.

I now have all the parts. I've built the electronics and the driver software on the arduino (well, I still have to include an acceleration profile and the code which stops when an end stop is reached). Even more I've tested it with a smaller stepper and it works! The big stepper arrived today.

I've also got the pulleys, timing belt and the bearing. And probably enough stock metal to make the bracket.

I'll post up a photo of the bits this weekend and of any progress I'm not too embarrassed about!

Who knows, it may even work!

I think the biggest challenge is going to be to get the motor lined up with the pulley so that the clutch engages correctly.

Iain

So I've got my design and I've started off.

The first step was the electronics, which looks like this

The motor on the far left is a much smaller test motor. The bigger beast next to it is the real deal.

Two oddities are the switch which appears to light up when off. Hadn't expected that (or have any idea where it cam from) and the motor drive socket is too high, the switch interferes with the eject button. it still seems to work with a bit of a wiggle, though.

And the working bits. On the left an arduino nano on some veroboard. I'm afraid I've never got to grips with making PCBs so it's old school. At the bottom a 24V 15A power supply and the black box claims to be a TB6600 drive. One thing I forgot when designing the front panel was indicators, so I'll be drilling more holes soon.

Incidentally, the way I made this was to do a design in OnShape, make a drawing, stick it to a piece of aluminium plate and drill, file and whatever against the template. Some of my filing's a bit rough, but it's hidden by the DB9.

All of these bits (apart from the motor I already had.

Next the hardware side

The flat bits are for the mounts, the wide round steel bar for the dog clutch, the thin bar for the axle, the aluminium bit (probably) for the new handle and the pulleys, belt and bearing are obvious.

The plans are shown below

Obviously the timing belt is missing between the two pulleys. THe first thing to make is the backplate

And the rest of the frame. The dog clutch is the only other difficult part (I hope)

Iain

Rightio. A bit intermittent over the last week, but progress has been made.

Here's the backplate (as above) plus the motor mount. I got the motor mount trimmed to match the backplate and then clamped them together to drill holes for bolts and, more importantly as pilots so to speak for the bearing and motor itself.

The motor plate motor recess was done on the lathe – spending (much) more time centering the 4 jaw than actually machining.

I swear that I get the direction to move the piece wrong at least one time in three!

The hole for the bearing in the backplate was done with a boring head, the new mill being a MUCH more pleasant instrument to use it on than the tiny CMD10.

One thing which was less good was that my (fairly) new co-axial indicator seems to be positioning the head a bit to the right of the actual centre. I can't even imagine a mechanism for this, but checking with a dial test indicator seems to suggest this. For now, I'm ignoring this issue, but I will need to review sometime soon .

I've also cut the axle to size, bored out the pulleys and started work on the dog chucks. The idea is to cut them on the mill in a hex ER32 collet, so I've cut a 40mm x 18mm cylinder as the support for a 40×10 cylinder. One done so far. I can't really take a cut bigger than 0.5mm on my lathe so it takes quite a while to reduce from 40 to 18, You can see the first one in the bottom right

Here are most of the bits.

Tomorrow, with some luck, complete the preparations for the dug chuck. Not sure I'll get to cut the faces though.

Iain

This is a bit of a catch up on stuff that's been going on for the last couple of weeks.

Following making of a Spindle lock for the mill, I cut the 4mm keyway for the 12mm shaft of the leadscrew in one pulley.

And a 3mm one in in the steel dog clutch half.

I thought I was doing well, but then I put it all together and found that the bracket is miss-sized (or the size I used for the pulley in the design was wrong) which meant it wouldn't fit. A bit annoyed by that.

After a few minutes expressive language, I realised that I could remove the bottom plate and replace it with two bars, one at each end where the bolt holes are. I believe I'managed reasonable precision (within a thou) of the length, so it may even be better.

It looks like that works (sadly no photo, but I'll take one when all the bits are together). The dog clutch parts engage with the various turning bits mounted by hand.

With that, I Loctited (638) the bearing into it's housing and left it to dry. Next is to loctite the shaft into the bearing and make sure everything moves freely. This is the bit which scares me the most as the tolerances are pretty tight.

Whilst waiting for the loctite to set, I started on the replacement handwheel which will get bolted to the X axis pulley.

I have a piece of 4 inch aluminium bar sourced from some show somewhere as a, 'That will be useful someday'. Well it will be, but I hadn't considered how I would cut it if it was wider than needed.

In the end I drilled and tapped the hole which the handle will go in, bolted it to an angle plate and clamped that in the jaws of the bandsaw vice. This lets just enough poke out.

Whilst this makes the job possible (and lets start by saying that cutting it by hand isn't work considering), it's going VERY slowly. I've got about a quarter of the way through in about 15 minutes.

I expect this would go better with a blade with coarser teeth (as it says on the machine), but I only have the one. Hmm. It might actually be worth investing in a coarser blade. The time it would take to swap the blade would hopefully beat the time saved in the cut.

I'm also thinking about automating the thing. Very brutal engineering. Basically just hang a weight on the end of the saw! I've already got a clip to keep the trigger down for when using the saw table.

Hopefully, next time I post, the mechanics will be done….

Iain