Faceting machine head assembly.

[Faceting Frank]

Found some code that will change the millis delay time using a potentiometer and another one using an encoder. That way I could dial out any screen display flutter to suit the lap speed. Way over my head as to how I could incorporate it into my code, so won’t bother with that idea. Have your code on displaying an average angle put where I think it should be RC, but // out at the moment. Busy wiring up the control box with my other esp32 board, screen etc.
Will get that working with the encoder next to the PC before fitting it all, hopefully It will be working on my machine next week. Have a spare push button wired into it for the 90deg reset, which Toms code does not have and must be set by changing line 29 of his code.

[Alaskan]

Frank... has 'lap flutter' been identified as a percentage of 'lap' versus Lap Plate clearances of the machine to motor?

Have you been able to look at 'flutter' of the platen and guess at a value... probably a dumb question?

Would an otherwise imperceptible clearance at the interface of the platen-nut to the master/lap hole cause this flutter and is there a material that might fill that clearance?

I know... toothpaste. 🤦‍♂️

Awesome accuracy work you are doing with Arduino!

[Faceting Frank]

All my laps produce flutter Alaskan which shows up on the dial gauge, some worse than others. My cutting laps are the type with diamond bonded to thin metal with a sticky back that glues to a 10mm thick ally lap. Not a perfect fit, but I find them better than the none sticky back type that just sit on the lap as you tighten the nut, some of them are not perfectly flat and the flutter is terrible.
The platen is not perfect and I have a bit of brass shim on it to cancel that out, the laps are marked on the side, so they go on the same way each time. For some reason the flutter differs if they are put on in a different position. So, by trial and error with a new lap I find out which is the best way to fit it.
None of this movement is major, about 0.03mm on the dial gauge with my 1200 lap, but I like to use the dial gauge as a stop and do that by looking at the top of the needle stroke. You can’t do that with a flickering number. What Rough Creations has done to solve that is to print on the screen the average reading of every 7 times the encoder sends info. I think that is what’s happening. So, any flutter on the screen is only 1/7th of what it would have been.

My ideas are all theory, because I have not fitted it to my machine yet. The dial out the flutter to suit the lap speed is now dead. My next crazy idea is to alter the delay time in the loop of the program to suit a particular lap speed. The loop is the working part of the program, it goes round and round and, in this case, gets info from the encoder and prints it on the screen as an angle. The current delay in the loop is 100ms a tenth of a second is = to 600rpm. So, at 600rpm the flutter should be minimal, maybe?

[Alaskan]

I have one 10mm cutter with a stickyback 600 grit the rest are steel/Diamond plasma sprayed by the look of them. When stickyback are worn out/used up - how do you remove them from the master?

I've a couple copper laps and a Batlap but my go to polishing laps are Corian 10mm which are similar to the aluminum master laps in dimensions & size (8").

I see flutter on my dial indicator in a value of ~ 20-30 hundredths if carefully preforming a round for girdles from 2500 grit on a master to start polishing wi Corian at 3000 grit.

Right now I'm getting an unusual frosty surface along the cylinder length with areas of polished lab created zircon on my Corian with 3000 Diamond/saxophone oil slurry which is not normal.

Today I'll try slowing down from 50% to 30% lap speed and look for a change. Your description of marking laps with marksalot makes a point I'll start tinkering with.

thank you for the in depth look at your work - the materials I cut are eBay and probably junk but always surprises me with sometimes good or bad outcomes ~ 50/50.

[Alaskan]

I'm having a problem finding my way around here and not seeing this in 'recent comments' - after replying with thanks - ?

Replying to Faceting Frank's reply of yesterday?

[Faceting Frank]

Got your email Alaskan, have no problem talking about laps etc. If you want to look at older posts, you will see page numbers at the top and bottom of the current page.
From memory I removed the sticky back laps by putting them in hot water first to soften the glue, but then they still took some forcing off with a thin metal blade. Tried one of those magnetic laps to put the none sticky diamond laps on. Great difficulty changing the laps, so put oil on it to make it easier and found the flutter was terrible.
There is a company here in OZ, gemcuts.com.au, that sell precut pieces of synthetic rough, mostly Cubic Zirconia at great prices. There should be similar retailers in your part of the world. Cubic Zirconia will produce a brilliant cut stone without any hassle. Finishing off with a 1200 cutting lap, then 3000 diamond on a BATT lap and 60k diamond on a BATT lap. I use baby oil, but any light oil will do. The only hassle with the above is keeping the 3000 diamond off everything, machine, hands etc. or eventually it will find its way onto the 60k lap.

[Alaskan]

Thanks Frank... solid gold information - I'm going to look at gemcuts.com.au  - cheers!

[Faceting Frank]

Got the enclosure wired up and working next to the PC, still waiting for my tube of liquid insulation from eBay to paint on exposed wires. Come up with the idea of securing other connections to the board and screen, by gluing a strip of plastic to the push in connectors. That way they become an entire push on plug.
Didn’t bother setting up a remote reset button, just cut a hole in the bottom of the box for my finger.
Still working on setting the 90deg with a push button. Have the button, LED light code installed to make them both work. Just the actual code that goes with it to make that happen. At the moment it seems to be changing the number on line 29 of Tom’s code to set the 90deg position on the encoder.

[RoughCreations]

Looking good. Another option for connecting wires to screens and the like is the use of Dupont connectors and a hand Crimper. They are cheaply available from Ebay as a complete set, see below.

RC

[MakkyBrown]

And they are fiddly to crimp nicely  but at least using the connectors, you can use copper wire as many of the ebay/aliexpress jumper wires are made of steel, test with a magnet.

[Faceting Frank]

Not sure if the crimped connectors would work in this situation. I was not going to glue the DuPont cables to the screen or board, but to each other to create a multi pin plug. Not with plastic glue either so I can't get them apart, but with quick grip. Already tested this and it works well, individually the cables are a pain as they easily come out. But as a group they are a firm fit.

[Faceting Frank]

Got the encoder fitted and working, calibrating it to 90deg took just a couple of minutes. Just temporary wiring from the box to the encoder at the moment. Ordered some 50cm long Dupont cables, that’s more than long enough to go from the encoder to the box. The box being fitted to the top of the light post, which is fitted to the mast base.
Looking forward to cutting my first stone with it.

[Alaskan]

Excellent,  Frank - encouraging as I'm too old to spend months experimenting - will you be able to repeat this experiment using your program and hardware assembled?

The results being tested... how are you checking for a 'golden master lap' to digital readouts?

[Faceting Frank]

I am going to start a new thread shortly on how I put this together Alaskan. With acknowledgment of the help I’ve had from both MakkyBrown and RoughCreations, as well as the YouTube vids worth looking at. I will also post my code, which is based on Tom Herbst code version 1 which you can download from his website facetingbook.com.
I spent a couple of hours cutting the girdle of a new stone yesterday using my 320 grit lap at full speed.  That lap runs out at 0.1mm on the outer edge, which is where you have to cut a girdle. To my surprise there was no flutter on the screen and it was easy to use it as a stop, cutting to an exact 90.00 angle.

[RoughCreations]

Congratulations Frank on getting it all sorted, and up and running - you have done a top job there. Testament to your impressive technical and trouble-shooting skills.
The best thing is, if you don't like some aspect, you can just update your code, add a new component like a screen or extra knob. You're in control.

RC