Ready Steady Eddy

[cncJim]

Thanks for the explanations eddy. Machine is looking great!

[EddyCurrent]

Without a doubt the Z axis is the hardest part, progress so far.

I used a bandsaw to cut the profiles and then a static belt sander to clean up the profiles, internals cleaned using files. The motor mount consists of two 6mm plates which are glued and screwed together, the motor adjustment slot and slotted holes were cut using a drill, files, flapdisc.
The backplate where the ball screw is attached was 'milled' using my overhead pneumatic pin router and hand guiding the aluminium plate against a straight edge that was gradually moved across half a cutter width at a time.
The cutter was a standard cheap 2 flute 6mm dia. TCT router bit running at 9000 rpm and it worked great, only clogging if my depth of cut exceeded 0.5mm, I had a good jet of air blowing on it and just cutting dry.

[fvfdrums]

Looking good :)

[njhussey]

Looking good, like the look of lots of shiny aluminium. My build has stalled...

[EddyCurrent]

Looking good, like the look of lots of shiny aluminium.

But it's knocking my pan in all the swarf and chippings underfoot, that's why I stick to wood

My build has stalled...

Not good, but it sounds like you have a lot going on just now.

[EddyCurrent]

I did a daft thing yesterday and tried to knee jerk my out of it but I knew it was no good and laid awake from 6am this morning thinking what to do, anyway it's back on track now.

I thought it would be a good idea to mill two grooves for the Z axis rails to sit in, maybe 0.5mm deep so using my wood router I set about it with a 6mm cutter. After installing the rails and sliding the assembly into the bearing blocks it was tight, noisy, juddering. So further investigation revealed the two grooves were not flat and the rails were leaning outward a bit, now this is where the knee jerk bit started, I put epoxy putty on the back of two of the bearing blocks and bolted it back up, it was better but not perfect. Anyway after thinking about it this morning I decided to route the grooves again but this time using one large cutter and it worked great, it took two goes to skim it but the results are so good there is virtually no resistance when sliding the front plate along. It meant though that I needed 1mm shims under the bearing blocks due to the extra depth I had to take out of the rail grooves but that worked out fine. There is a slight gap each side of the rails due to the grooves being slightly wider however I will run a bit of epoxy into those gaps and that should keep the rails nicely in place.
I'll have to divert onto another bit now as I'm waiting for the Z axis ball nut to arrive from China.

Extra hole in rail = broken tap in orignal.


clamps are to stop front plate dropping out of the bearings and loosing my balls.

[njhussey]

Looking good there , nice to see it all coming together.

[EddyCurrent]

Compound brackets for ball screw FK12 / FF12 type bearings, this is how I made them.
Clamp all parts of bracket together, position bearing block on brackets and clamp, drill 4 mounting holes in brackets using bearing block as a guide, disassemble bracket pieces and drill largest feasible hole in each piece, in my case about 19mm using a cone cutter (it's hard work and hardly cuts), bolt bearing block to a bracket piece with some spacers between, mount in lathe chuck, use boring bar to open hole out to final size, repeat for other bracket pieces.



Ball screw mounted to gantry, it was on and off so many times it could have put itself together in the end, this was due to adding shims here and there to get it working smoothly. I was forced to sup a can of Guinness to use the cut up tin for shims.

[Jonathan]

Wait, you have a lathe yet you were asking to buy a BK12 bearing block, instead of just making a better one. This makes no sense.

[EddyCurrent]

Wait, you have a lathe yet you were asking to buy a BK12 bearing block, instead of just making a better one. This makes no sense.

Edit: Previous ramblings removed.

I bought some sausage for breakfast but we have a mincer so why didn't I make some better ones, I got some logs delivered for my stove but I have a saw and an axe so why didn't I got into the wood and chop some better ones, I bought some cheap jogging trousers to wear in the shed but we have a sewing machine so why didn't I make some better ones, I bought some aluminium but I have a gas burner so why didn't I melt some empty Guinness cans to make a better billet ?

When I used to do peoples annual appraisals at work there was a criteria called 'Seeing Patterns', so do yourself a self assessment on this and there's your answer.