Started building at last!

[The Wizard]

Hi folks, I guess my building project has finally started after many weeks/months of planning, reviewing, playing with software etc .

My motors and controller came in on Thursday so I spent yesterday and today gutting an old 386 computer for the power supply and case and carrying out motor tests (I just couldn't resist spinning those motors ).

I searched high and low for a large heatsink I know I have here somewhere but of course with moving house twice in two years it's not to be found! In the end I decided to pull a pair of heatsinks off the 386 motherboard and used those to mount the power resistors on. I even mounted a 12V fan to help keep them cool.

The motors fired up at the first attempt and ran nicely (one is not quite as smooth running as the other two so I will use that one on the Z axis). I ran several batches of code through them using a number of different pieces of control software and the motors stayed cool throughout and the resistors were warm but not hot (you could easily leave your hand on them).

I have attached a photo of the test set up (ignore the rat's nest.....lol......it will be neater when complete. The controller is a Stepperworld SP-3HT and the motors are Superior Electric 75 oz./in. units.

Now I have to start on the woodworking side and get the machine built!

Larry Green

[CNCadmin]

Nice great start please keep us up to date on your progress.

[The Wizard]

I still haven't been able to access my buddies wood shop but I have now priced the MDF for this project ($46 CDN incl. taxes) and in the mean time I have been busy making some parts that I can work on here. The first project was a set of three self-adjusting AB nuts. I decided to go with this design rather than a split type with adjustment screw as I had some round nylon bar available plus it gave me a chance to play with another toy of mine.

I have a Unimat SL/DB200 table top lathe/mill (early 70's vintage) and I was just about on it's limits in terms of size with these parts. 1.5" is about the maximum diameter you can hold in the chuck (with the jaws reversed) and the stock nylon bar was 1.5" diameter. Unfortunately the torque at that diameter meant I could only take 10 thou cuts otherwise the belts would slip so it took a long time and lots of winding those tiny handles to turn these parts but it was interesting and gave me a sense of achievement when it was done.

The slots were cut with the Unimat in mill mode using a .120" burr from my Dremel. I could only take small cuts again as I didn't want to break the only suitable cutter I had plus it tended to flex on the male part if the cut was too large.

The springs I found in the local hardware store and have a free length of 1.5" and compress to .5". They are 5/8" diameter and use .040" diameter wire. They load up nicely and have enough tension to do the job.

I made a tap out of a piece of 'all tread'. I turned a taper on one end and cut the slits with a cutting wheel in my Dremel. I also centre drilled the end so that I could support it on the lathe. With a centre in the end the tap started into the hole square and true. It worked quite well considering what it was but I may have to run it through the nylon a few more times (or open up the hole one drill size) as it is a bit 'tight' on the 'all thread' and I can see the motors having to work hard just to turn the leadscrew in the nuts.

I have attached a few photos for your viewing pleasure . More info to follow as the project progresses. It will be next weekend before I can start on the wood so I think some handles/knobs for the motor shafts are going to be next.

Larry

[Mr.Chips]

Larry,

Thats a good looking AB nut. Any new photos available?

Hager

[The Wizard]

Larry,

Thats a good looking AB nut. Any new photos available?

Hager

Thanks Hager. Those are the latest photos I uploaded them as soon as I had the parts finished.

I will post more as I get parts made.

Larry.

[The Wizard]

I decided to make the handles for the motors yesterday/today. These will allow me to turn the leadscrews by hand for set-up purposes or to back off the axis from a limit switch.

The grey parts are PVC and the black parts are polyethylene (material I happened to have available). The shoulder bolts allow the 'knobs' to spin freely while still being held securely. I also had to make two more taps (10-24 and 10-32) out of machine screws. Gotta love home made taps in plastic .

I have also cut the aluminum linear bearing carriers to length so this evening may be spent drilling holes for the mounting bolts. I am just hoping my tiny Unimat is up to the task....lol.

Larry

[High Seas]

Wayyyy Cool.

[The Wizard]

Wayyyy Cool.

Cheers High Seas!

[The Wizard]

Well it's been a busy week or so here and I have been pushing my tiny Unimat to the limits (and beyond) again!

I got the aluminum linear bearing supports made but unfortunately the Unimat wasn't up to the task of cutting the slots using a burr from my Dremel (no metal cutting end mills available) so I had to resort to the old skills and cut them out by hand using a hacksaw and a flat file. I have a medical disability that leaves me extremely tired after only a small amount of effort and all that hand working meant that I had to cut one pair of flats and then go and rest for a couple of hours to recover! Nevertheless I got them done and I just need to get the hardware to mount the skate bearings.

Next up was the adjustable blocks for the rails/pipes. This again turned out to be a big task as my material was slightly wider than required which meant I had to machine them all round using a 1/2" wood router in the Unimat. Once I had them square and to size it was on to the holes (all 108 of them!)

The mounting holes were nice and easy as I set up a jig on the Unimat so that I could just slide the corner into position and drill. The only downside was the whopping 3/4" of travel on the Unimat Z axis. The material was 3/4" thick and by the time you add in the point length on the drill and a bit of clearance above the part it meant that I had to flip the parts over to get a hole that went all the way through. Thankfully my jig was spot on and the holes lined up perfectly.

The large central hole was next which meant tearing down the Unimat mill/drill set-up and reconfiguring it as a lathe. All I had to make the holes were wood cutting spade bits so that was what I used.

The first problem I encountered was the fact that I could not 'swing' the larger of the blocks in the 4-jaw chuck as the corners of the block fouled on the bed. After some head scratching and pondering I wondered just how much I would have to remove from the corners to get it to 'swing'. Out came the Exacto knife and I started to pare small amounts off one corner until it cleared the bed. As it turned out I only needed to remove 1/8" at 45° so the corners of the four larger blocks got a quick trim and away we went!

The next problem to raise it's head was the fact that the Unimat just didn't have the power to cope with a 1-1/4" spade bit straight into the nylon. This meant that I had to work my way up in size but it also meant that after the first hole was drilled there would be nothing to guide the spade bit. I also placed a variable speed controller in the line so that I could slow the Unimat down as the slowest available belt speed was way too high for the spade bits. As it turned out the spade bits ran nice and true and didn't really need the point to centre themselves in a rigid lathe set-up. The finish was very good, almost glass like, and I was impressed with the way they cut nylon. It took a while to machine all the holes with having to go up in steps of every other size but I got there in the end. It helped that the smaller blocks only needed a 1" hole too.

Once the large holes were done I had to reconfigure the Unimat to mill/drill mode again so that I could drill and tap the adjustment screw holes. After the large holes this was a breeze and only took half a day to drill and tap all 48 holes.

I have attached a few photos and have more of the various set-ups if anyone is interested in seeing what I had to do to make these parts.

If things go according to plan I should be starting on the woodwork next weekend as my buddies woodshop is finally free (he has had an active project going on and wanted that out of the way first). More updates as they are available!

Larry

[The Wizard]

Hi folks,

Sorry it's been so long since my last update but shortly after my last post I ran into health problems, financial problems and car problems (all in the same week!) These set the CNC project back quite a bit and then I had some 'must do' projects that had to be finished before Christmas. At least I did manage to get over to my buddies place to get the MDF boards ripped to size.

Since the New Year I have been going at the CNC project full tilt again and I am starting to make real progress (albeit slow). I am hampered somewhat by a lack of decent machinery and I am pushing my tiny Unimat DB200 to the edge and beyond with this project. I am having to make 9-10 cuts for grooves that could be cut in one pass with a decent router table (with micro adjustable fence) and the right size cutter.

I finished the last of the 'critical' grooves this evening and started drilling holes for the numerous bolts. With a bit of luck the majority of the Z and Y axis components should be ready to assemble tomorrow.

Over the holiday period the connector parts arrived for my wiring and I have already made up the 'unbilical' cables that will run between the control box and the machine and made mounting plates for the 'uni-lock' connectors. Now I just have to find a suitable switch to use as an E-stop and a 12V DPDT relay and the wiring side will be sorted as far as parts are concerned.

I will post more photos as the job progresses (there hasn't been that much to photograph recently...lol).

Larry

[MIKE JEFFERS]

like the spinney spinney photo (drill swarf etc)
living i canadia as you do its probably 12 feet of snow outside best get on then
like the uni mat
regards
mike

[The Wizard]

like the spinney spinney photo (drill swarf etc)
living i canadia as you do its probably 12 feet of snow outside best get on then
like the uni mat
regards
mike

Thanks Mike.

Although I am in Canada I am an ex-pat and have been here 12 years now. Thankfully we haven't seen 12 feet of snow this year but we have had snow on the ground almost continuously since just before Christmas and it is finally disappearing now.

As far as the machine is concerned........I have been busy as a beaver over the winter cutting and painting the wood parts and assembling the major components. Tonight we finally got the rails and gantry mounted on the bed and roughly lined up and tomorrow we will fine tune it and start on the Y axis.

I haven't posted any more photos recently as I felt everyone on here had seen enough photos of wood parts and drying paint but I will post more after we get the main assemblies mounted tomorrow.

Watch this space

Larry