New Machine Build- Sort of - Upgraded my JGRO

[uspl]

Hi all

Had a very satisfying day today; I managed to triple the speed of my JGRO for a total spend of $240.

I visited MP Sinclair P/L in North Coburg and got three lengths of 1/2" 8tpi ACME and six nuts to suit for $200. Next stop was Naismith Engineering in Northcote to collect $40 worth of Lovejoy couplers.

Last stop was the local $2 shop for some plastic chopping boards

That done, I returned to my secret lair.....................

JGRO Mk1.0 went to work and made the plates you see in the photos. The chopping board became two plates to create a housing for the ACME nuts.
The new plate is bolted to the base of the gantry, added some candle grease and some CRC 5-56 and zero backlash with silky smooth travel was the result.

The Lovejoy made quick work of fitting the thread to the existing motor mount.

A bit of tuning in Mach3 and I am now getting almost 1000mm per minute from the X axis. Y Axis is tomorrow.

Cheers

David

[DeadTom]

Nice idea but you had better have your backlash set (appears to be no adjustment) before you mount the assembly to the gantries.
Tom

[uspl]

Originally Posted by DeadTom Nice idea but you had better have your backlash set (appears to be no adjustment) before you mount the assembly to the gantries. Tom

Hi Tom, thanks for looking.

I found that by adjusting the nuts 1/8 of a turn at a time them assembling the plate I got to the point of no discernible backlash. It was trial and error of course but the machine screws are quick to add/remove and it only took half a dozen goes to get it right without having too much tension and hence friction.

Although there is no adjustment once assembled, there is nothing to work loose and go out of whack either

BTW, For those in Melbourne looking for engineering support, Matt at Sinclairs is a dream find. Imagine your best vision of a 1950's engineering shop, every lathe, press, drill and sundry machine you can think of accompanied by rack after rack of tube, flat, section & rod in brass, steel and aluminium. Now add Matt, a guy in his late sixties or maybe seventies who is engineer, toolmaker and designer. We spent 30 minutes discussing all sorts of options for getting DIY CNC just right and he was happy to take the time. A really nice guy who could pretty much supply or make pretty much anything you might need in that line of kit.

Cheers

David

[DeadTom]

Very good David, the name of the game is DIY and that means anything goes.
Good luck and keep us posted as to your progress,
Tom

PS - Matt sounds like a real good person to know

[uspl]

Hi

DIY indeed.

I found an alternative that seems to work well, though it may have been more good luck than good management.

I had a section of 25mm x 100mm HDPE left over from my original build so I decided to try making a nut from it.

First I drilled a hole 1/4" in diameter through the slab as a pilot hole. The I drilled exactly 1/2" in diameter about 10mm into the plastic. The final drill was 12mm all the way through, so slightly undersized for the AMCE thread. I put a short length of ACME in my electric drill and spun it for a few minutes in the larger hole.

The result was very quickly a very hot piece of threaded rod, hot enough to sizzle and smoke when I sprayed the threads with CRC. I placed the rod in the vise and slowly pressed down and turned the plastic block by hand, forcing it onto the rod while keeping it as flat and straight as possible. It was surprisingly easy to do and soon the rod had cut all the way through making a thread as it went. Back to the electric drill setup and some lubricant, back and forth through the block a few times.

A final trim up on the drop saw and I have a perfect fitting HDPE nut with no slop and plenty of fixing area for the gantry to mount on. I'm sure I was lucky keeping the nut square as it cut the thread but the original 10mm deep hole seemed to be enough to act as a guide.

I love this stuff !!

Cheers

David