Max's Build - a comedy of errors.

Max Metz
Posts: 240
Joined: Sun May 20, 2012 11:55 am

Max's Build - a comedy of errors.

Post by Max Metz » Mon Aug 27, 2012 6:07 pm

A few days after the full kit arrived, I began my build, taping the holes in the end of the Makerslide seemed a good place to start.

Using wd40 and tapping a little bit, then re lubricating and cleaning the tap before continuing seemed to be going well.

Half way through tapping the tap shattered, breaking off in the hole - worse as the tap broke the jagged end hit the v rail leaving a dent right at the top. There was a little bit of the tap protruding out of the end Makerslide hole but every time I tried to grip it the brittle metal of the tap would just crumble away. Finally I ground down around the extrusion hole, down about 5mm, without damaging the surrounding end flat surface, then there was enough of the tap to grip with pointy nose pliers and out it screwed.

The dint was right on the top of the v rail, I remembered the wheels run either side so I used a very fine cushioned emery board to remove and smooth the tiny edges of the dint and the v wheels seemed to slide over the section cleanly without dipping down - that was a relief.

I then used my own tap which was tool steel and finished the job. This time though I tapped deeper, around 15mm as I noticed the extra depth needed on the hole that I ground down seemed much stronger.

I attached the end plates to the x axis Makerslide, fitted the top v-wheels and single idler to both outsides, screwed my stand offs to a motor - alas I overdid one and it snapped off in the hole! No worries as the top motor only uses 3 motor holes to secure it - I'll have to be much more gentle from here on with the brass standoffs, I should have known that to begin with.

Next came the threaded shaft running across the x axis to drive the y axis with 2 belts and one motor. The bearings fitted well into the motor plates after removing the tiny burs on the stainless steel, the Teflon tape took up the slack in the centre 5mm hole before tightening the bolts on the inside. Trouble came when the pulley worm screws where unhappy with the threaded rod, a nut either side of the pulleys solved that and filing down the nuts to half their thickness allowed the assembly within the available space.

After full installation of the drive shaft assembly I stood back and admired how it looked, gave it a few turns and was feeling pretty pleased with myself. My self gratification came a little premature, the 5mm shaft didn't have enough rigidity to hold the bearings against the plate revealing a little gap opening up on one side as I played with it and worse - the pulleys flexed with the shaft as the bearings acted as node points. I though of adding an outside bearing flange - no, adding a new bearing flange on the outside may hold the bearings secure but it would not help the nodal flex problem.

I disassembled the shaft and re attached the motor to one side - I would need another motor on the other side or to build a separate pulley assembly with its own shaft on the other side, each pulley having its own own shaft , those shafts and not the pulleys themselves would then be connected to the threaded rod in the middle. Ironically, it occurred to me that the simplest way to do this was with two motors, one connected electrically while the other one had everything removed inside bar the motor shaft and bearings. Oh well.

I contacted motor factory in China and they have agreed to supply and ship me a second identical y axis motor to power the pulley on the other side.

Next came the making of the aluminium spacers to extend the travel in the x and y axis - making little 3mm thick spacers 20x40mm with accurate holes that align with those in the Makerslide proved a real challenge with a hacksaw, metal file and drill. After some practice and quite a bit of time I got there and installed the same. Instead of making the spacers 5mm total each end of the x axis and 9mm each end of the y axis I made them all 9mm - 3 pieces of 3mm aluminium each. I then cut and drilled 8x 10mm square 4mm spacers for the v-wheels on the motor plates - making the difference 5mm as planned but increasing the X axis travel the full 18mm total, while still being able to line up the Makerslide end bolts within the tolerance of the horizontal holes in the thick end plates which had dictated the 5mm maximum x axis spacer width originally.

When I went to buy the make a bracket, the holes were not on a 20mm grid as specified; they were 20mm one way, 25mm the other - lucky I noticed. It will be just as easy to make some custom brackets out of aluminium for the rest of the build.

So then, next up I'll buy some more threaded rod, nuts, washers and aluminium for the belt/optical sensor brackets and make those.

Best regards. :D

edwardrford
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Re: Max's Build - a comedy of errors.

Post by edwardrford » Mon Aug 27, 2012 6:50 pm

That's fantastic Max. I know you had a lot of obstacles to overcome first, but it sounds like you're getting there. Plus, considering how much of a departure from the 'stock' design your machine is (going to be), I find it amazing that you've come this far so quickly.

On a realated note: Each time I read one of these build logs, the smile on my face gets bigger. The title of your build log made me smile even more. I'm sure it's somewhere in the google group archive, but I'll re-tell the story fo posterity's sake:

In the beginning of the rewards fulfillment part of the project, I set about assembly 6 machines simultaneously [btw: I know that batch assembly is a *rule* breaker for any lean fanatics out there!]. The reason for the pre-assembly was an extra diligent way to make sure I was packing all of the components! Well, one thing led to another and I had half completed all 6 of the units. I stood back and cracked celebratory beverage of the Ale variety. How proud I was at myself.

Wait... something looked wierd... damn it! I had assembled all of the motor mounts in the same orientation.. so for half of the motor mounts I needed to remove all of the v-wheels and put them on the other side of the mount... OK, not a huge deal. I spent the time and re-worked them.

The next evening I ran out of M5x30 SHCS...

The next evening I ran out of M5x10 SHCS...

The next evening I realized I needed stepper motor cable...

I finally had the 6 units completed! Here they are
shapeoko_6_pack.jpg
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Then I needed to disassemble all of the units and flat pack them in their USPS boxes. Done!
Then I needed to print a label. Done!
Then I scheduled a pickup from the post office. Done!
Then they picked up the packages. Hooray!
Then all of the packages were back on my doorstep the next day... wait... what?!

Seems that you need to add *postage* to the labels... not just print labels off and expect them to ship for free...doh!

In the end, all of the units shipped. However, all but 1 of them was 100% complete.. i had forgotten something in 5/6! Pathetic that I had spent the time to pre-assemble and test the machines only to simply forget to put an item in to the package...many follow up shipments were required.

It makes me laugh now, but at the time I was not laughing. At all.

Anyway, I suppose my point is that it's all part of the *fun*. At least I hope it is :-)

-Edward
Shapeoko 1 #0 - a couple of upgrades.
Shapeoko 2 #0 - a couple of upgrades.
Shapeoko 3 #2 - Stock

Max Metz
Posts: 240
Joined: Sun May 20, 2012 11:55 am

Re: Max's Build - a comedy of errors.

Post by Max Metz » Tue Aug 28, 2012 3:14 am

Thanks Edward.

Your encouragement is much appreciated, if nothing else the moral of the build so far has been one of learning some extra patience, standing back and just whittling away at the task - as my father would say, "...quietly as she goes."

As I read your story, its a wonder you didn't loose it, thought you never let it beat you - just kept going until the machines, their assembly and dispatch was top notch; which is a testament to your high standards and staying power.

Yes, I am enjoying the build very much, despite the test of patience, all that drawing is a huge advantage and it's is fulfilling to see known pieces going together in a familiar way - rather like a Mechano set for those of us that never grew up, a welcome return to play. lol

Best regards mate. :D

dointhangs
Posts: 179
Joined: Tue Jun 05, 2012 7:31 pm

Re: Max's Build - a comedy of errors.

Post by dointhangs » Tue Aug 28, 2012 4:07 am

I'm tapping some makerslide tonight to extend my x-axis and your tapping story here has me absolutely walking on eggshells!! very nervous haha! I am intrigued by your description of the ideas to run both axes with one motor although it sounds like it didnt work out so well and then you describe some interesting bracket ideas I hope to see pics of someday. Cheers on being very brave with this project...
Shapeoko #298, dual drive upgrade, acme z axis, open bed endplates and a slightly larger ("expanded desktop") work area!

Max Metz
Posts: 240
Joined: Sun May 20, 2012 11:55 am

Re: Max's Build - a comedy of errors.

Post by Max Metz » Wed Aug 29, 2012 12:11 am

lol dointhangs.

I think I was just unlucky with the tap, it could happen with any brand, just a small inconsistency in the brittle tap metal - my guess is you will be fine.

As for the shaft powering both sides of the Y axis, I had to pull up quite firmly on the threaded rod shaft to see the gap open up between the flanged bearing and the left side motor plate, so it was not immediately obvious. Anyway it was worth a try, the extra motor should be on its way from China today or tomorrow.

Most importantly, thanks for the encouragement mate, very much appreciated - enjoy the day. Best regards. :D

cvoinescu
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Re: Max's Build - a comedy of errors.

Post by cvoinescu » Wed Aug 29, 2012 8:17 am

Max, I don't have a clear mental picture of how your shaft is set up, so I am probably wrong on this, but from your last comment it seems that the flanges of the bearings are on the inside of the Y plates. What would happen if you flipped the bearings so that the flanges were on the outside of the Y plates? Then flexing the shaft would pull the bearing in, not out, and it may help make the shaft stiffer.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

Max Metz
Posts: 240
Joined: Sun May 20, 2012 11:55 am

Re: Max's Build - a comedy of errors.

Post by Max Metz » Thu Aug 30, 2012 12:27 am

You are probably right cvoinescu.

My reservation is that the either way the shaft is either in compression, bearings held in on the inside or tension, bearings held in on the outside - both would likely cause the shaft to flex about two nodes central to the bearings. This is a sketch of what happens:
scan0001.jpg
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The tension and compression on the shaft needs to be balanced, there isn't enough guts (stiffness) in 5mm rod to do that and not enough room for a thicker rod. Its likely the best solution would be to go with the problem and design in the shaft as a flexible component with the two pulleys on two independent rigid shafts. The motor side is already on a rigid shaft, the motor shaft, the same needs to be done on the other side and then the two connected by the threaded rod which can then be flexing its heart out without undue effect.

I had to pull up quite firmly on the threaded rod to see the adverse effect with my initial set-up, though it seemed enough to be problematic. I may return to this shaft idea later, using the new motor for my 4th axis and making a rigid shaft assembly to replace it on that side of the y axis.

All the very best mate. :D

Max Metz
Posts: 240
Joined: Sun May 20, 2012 11:55 am

Re: Max's Build - a comedy of errors.

Post by Max Metz » Tue Sep 04, 2012 3:56 pm

After buying some 0.95mm galvanised steel sheet (300x600mm Bunnings), a set of aviation snips (3 for $9.90 Bunnings) and a small file set ($15 Bunnings) I set to work on the brackets - after some serious learning about working with sheet metal they are finished. I already had a Dremel with diamond bit, hacksaw, clamps and a vice.
+brackets 001.jpg
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I printed out a full size template of all the brackets and glued that sheet to the metal. Next, punched the hole centres and drilled a pilot hole followed by the full sized hole with a Metabo drill in a jig. Once that was done I hack sawed out the longer lengths (using the edge of a piece of wood as a guide) then used the aviation snips for shorter lengths making sure the scrap was the narrowest bit (so as not to unduly bend the brackets).

Using the small brittle metal files (8 shapes) I neatened up the flat brackets, the long enclosed holes were ground away with a diamond bit in a Dremel flexible shaft, again neatened up with the small files. The bends were done by drilling a small hole at either end of the bend, then this was made into an arrow with a v shapes small file - the bends were completed in a vice using a very small hammer, as planned the bends followed the line between the cut out arrow heads. Where two bent parts did not bend parallel as needed they were gently aligned using a small hammer and a punch.

Each plate was then labelled with tool steel letter punches - after that the 3 and 4mm bolts, nuts and washers were attached.

Finally the 4x 16mm mdf spacers for the front plate were cut and drilled, the edges bevelled, then micro waved for 30 seconds to remove excess moisture and given a coat of watered down Triton wood glue to seal against moisture and increase their dimensional stability.
MyBat Shapeoko mods 0015D 6A simple play.jpg
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This first drawing shows the brackets serve 4 purposes in the x and y axis - they stop the v wheels over running the Makerslide while the aluminium spacers increase the run by 9mm each end of x and y (229x229mm cutting area), hold the axis limit screws for the optical switches, hold the cable chain in place and finally they hold the belt ends in place and in tension. Other brackets hold the 6 optical switches and one lonely brackets holds the y axis drag chain horizontal (the whole drag chain length stays horizontal if one end is held so).

One bracket holds the 2 z axis optical switches centrally behind the z axis, these are activated by a small threaded pin perpendicular to and projecting from the rear of the z axis makerslide just behind the v rail.
MyBat Shapeoko mods 0015D 6A simple play 2.jpg
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The end plates on the x axis also allow 2 belt configurations, one of which only uses 1 pulley.

After a clumsy start I am starting to get the hang of this stuff. :D

Tom Smith
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Re: Max's Build - a comedy of errors.

Post by Tom Smith » Wed Sep 05, 2012 4:44 pm

I'm really looking forward to the photos of your implementations, Max, to see what your concepts look like in meatspace :)

Still waiting for delivery of some parts for my driveshaft modification, but will be sure to post some photos when I can.

Tom
_______________
ShapeOko1 191

Max Metz
Posts: 240
Joined: Sun May 20, 2012 11:55 am

Re: Max's Build - a comedy of errors.

Post by Max Metz » Wed Sep 05, 2012 6:02 pm

Thanks Tom.

My little X10 camera of choice for these things is currently winging its way back to me from the East of Australia following Fuji generously upgrading the sensor - when it arrives as an avid photographer I'll start snapping away. Actually I plan to use the Shapeoko as a focus camera rail as well as a cutting machine and scanner, perhaps my dslr will be too heavy, though the little x10 should be a doddle.

Its cool knowing that we are both in a similar time line with our cnc adventure.

All the best mate. :D

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