Chess Pieces - Pawn

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Chess Pieces - Pawn

Post by halftonner » Fri 09 Feb , 2018 18:34 pm

Decided to have another play at making the chess pieces from the original Orac instruction book ... but I now remember why I gave up with this ...

I'm running an Orac via Mach3 control, and I have 'transposed' (hand typed) the pawn piece as close as you can be from the written crib sheet from the Orac Manual into Mach3 version of G-Code. I worked out the coding and how to do the subroutines (old orac name 'Do xxx ' end 'do' etc) - and the visual representation on Mach 3 mimics nicely the drawing in the Orac brochure ... but the cut depths seem very scary as do the feed speeds.... scary enough to stall the motor on the lathe and cause me to 'whack the big red stop button'!!!

Surely the original Orac manual values are right??

Has anyone had a similar experience (or has anyone copied the official chess piece onto an Orac and made one successfully?
Yes I know I could put the outline of the chess piece into CAD and let the PC work it out for me, but half of the intended fun was hoping to see the lathe make a chess piece as it would have been when used back when it was released.

G-Code; if someone wants to try it on their machine: (Though I suggest free air cutting first!!!):

My tooling is set up as follows:
T0101 (tool 1) = 'copy tool 56deg tip (Orac manual = tool 2)
T0303 (tool 3) = 'R-H Turning tool 56deg tip (Orac manual = tool 1)
T0505 (tool 5) = 'L-H Turning tool 56deg tip (Orac manual = tool 4)

Parting off is (well would be if I got that far) by hand with a saw as I haven't yet set up the parting tool in the tool changer..

Mach3 is running in Radius mode, units of measurement = mm...

Code: Select all

G18 G21 G50 G80 G90 G94 (written in radius mode) (G90=Absoloute, G91=incrimental)
(Bar stock size 25.4mm x 70mm - mild steel)

G01 X15 Z5

M03 S1500 G04 P5

F1000 X-2 Z-4
M98 P1 Q4
F1000 X-0.5 Z0.2
M98 P2 Q4
F1000 X-0.98
M98 P3 Q3
F1000 Z-4.8
M98 P4 Q2

F1000 X3.4 Z-0.8
F100  X4.51 Z-4.6
F1000 X3.4 Z-0.8
F1000 X2.3
F100  X4.3 Z-3.5
F1000 X2.3 Z-0.8
F1000 X0 Z-0.85
F80   G02 X4.54 Z-5.39 R-4.44
F100  G01 X3.7 Z-9.7
F1000 X4.6 Z-6
F100  X2.8 Z-9.5
F100  X6.1 Z-11.5
F100  X6.1 Z-12.7
F60   X5.1 Z-14.4
F100  X5.1 Z-25
F1000 X5.1 Z-14.4
F100  X4.1 Z-16.3
F100  X4.1 Z-22.5
F1000 X4.1 Z-16.3
F100  X3.2 Z-18
F80   X3.6 Z-22.5
F200  X4.7 Z-22.5
F100  X4.7 Z-24.5
F100  X9.2 Z-32.5
F1000 X10 Z0
F1000 X0 Z-0.5
F30   X0 Z-1.05
F100  G02 X4.34 Z-5.39 R-4.34
F100  G02 X4 Z-6.5 R-2
F100  G01 X2.5 Z-9.5
F100  X5.8 Z-11.5
F80   G02 X5.8 Z-12.5 R-2
F100  G01 X3 Z-18
S1000 G04 P5
F100  X3.5 Z-22.5
F200  X4.15 Z-22.5
F100  X4.5 Z-22.85
F100  X4.5 Z-24.5
F100  X8.9 Z-32.3
F100  X9 Z-32.6
F100  X9 Z-39
F1000 X10 Z-39
F1200 X15 Z5

F1200 X10 Z-33.5
F100  X9 Z-33.5
F25   X8.3 Z-33.5
S1000 G04 P5
F900  X10 Z-33.5
F1200 X15 Z5

F1200 X10 Z-15
F900  X5.1 Z-15
F80   X5.1 Z-12.4
F1000 X5.1 Z-15
F1000 X4.1 Z-17
F80   X4.1 Z-12.4
F1000 X4.1 Z-17
F100  X3.2 Z-18.5
F60   X2.7 Z-12.4
F1000 X3.2 Z-18.5
F60   X3 Z-18
F100  X2.5 Z-12.4
F400  X10 Z-12.4
F1200 X30 Z5
F1200 X10 Z-36.6
F80   X7.5 Z-36.6
F1200 X10
F1200 X15 Z5


F1000 Z-0.5
F80   X-13
F1000 X13

F1000 X-0.83
F100  Z-39
F1000 Z39

F100  Z-29.8
F1000 Z29.8
F1000 X-1 Z1.6

F100  Z-10.1
F1000 Z10.1
F1000 X-0.75 Z0.5
pawn orac.txt
g-code as a .txt file ready to run in Mach3 on an Orac
(1.74 KiB) Downloaded 140 times

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Re: Chess Pieces - Pawn

Post by TDIPower » Sat 10 Feb , 2018 13:08 pm

Hi, Not on the ORAC (although I remember one of those stuck in the corner of the workshop at school as a kid in the mid 80s). I can only confirm I have had issues.

I have the starturn 5 which is also DOS based, I did OK turning the test piece OK after typing it all up from the manual. My problem has come from buying the latest quickturn software, I was aware that the threading code it generates would be incompatible so figured I could learn that part.
I CAD up some test pieces from the DOS manual but when I ran it I thought it was going to blow itself to bits! nearly stalled the motor and had me hitting the E-Stop
I had put in all the dims for the cutters on the ATC, the material spec etc and even generated codes for different machines from the Microturn (very small machine) to big machines. Looking through the code it was trying to take 2mm cuts off steel and despite having all the dims for the cutters inputted was going to cause major damage by trying to part off a piece of to large dia. I had hoped that although the piece was to large for my parting tool it would just part as much as it could then stop (this is what it does for drilling/boring, only goes to the depth of flutes).

I spent ages looking through all the files and machine settings but found life was passing me by again so left it. I'm about due to return to getting it running. I had considered changing over to Mach3 as I would have liked to move from DOS but figured after years of working with Denfords milling software that the turning software would be more straightforward for me. Alas denford don't seem to produce manuals/instructions of the same quality for turning as they have done for the milling.

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Re: Chess Pieces - Pawn

Post by Lone_Ranger » Mon 12 Feb , 2018 17:58 pm

Hmmm, sounds a little like the possibility of some confusion here regarding the use of "Radius" and "Diameter" modes, also the feeds seem to be quite OK, F100mm/minute is quite slow, the F1000 moves should be rapids between cuts ? ?

I had an Orac that I sold last year and that was on all the original hardware and software, it appeared to work in "Diameter" mode as when setting the tools and the stock at the end of a program the only value input was the actual Diameter of the stock.

So to remove say 2mm off a 30mm bar to get a 28mm bar the size of the bar was input ie 30mm and then to get a depth of cut of 0.5mm the program had to have 2 repeats ( Do Loop in Denford speak), this would have the X axis actually move 0.5mm into the material, which meant that in actual fact 1mm was taken off the bar diameter.
I have only ever ran any Lathe in Diameter mode, most Lathe controllers are usually defaulted to Diameter, much easier as usually the numbers on the screen are the actual Diameter of the material, eg Fanuc etc.

If you are generating code in "Radius" mode then the DOC will be double so this could be where the issues are, I never had a problem with my Orac and the person I sold it to is local and I know is still running it on the original hardware and software without any problems. Just for interest, it had the original PC containing both the old Milling and Turning software so a program could be written on the PC and then uploaded to the Orac control via the good old RS232 Serial cable.
Programs could also be saved to the PC which was great because the old Tape system was never very good :) :)

If you are all already familiar with all of the above then my apologies, if not then I hope it helps a little :) :)


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Re: Chess Pieces - Pawn

Post by halftonner » Mon 12 Feb , 2018 20:12 pm

Ta for that Rob ... I normally work in diameter too (Its a heck of a lot easier :) ) - however, the way the "demo chess set" is written in the Orac manual is in radius mode (so I turn the settings on the machine to run in radius mode) ... what it then means is its a 0.5mm deep cut (or 1mm off the stock) on each pass - at the spindle speed and the tool feed rate it is seemingly scary! ... maybe it's just me not being brave enough, but I'm sure something doesn't seem right to me - especially as when I last ran the program the tool dug into the material so hard it stalled the spindle and bent the metal stock! :shock:

Yes I could have written the feed rate of 1000mm/min as rapid traverse (G00) ... but I was trying to be faithful to the orac listing

Maybe I might be best to CAD the chess piece myself and then work out my own listing to make the piece :(

(If I set the machine to run diameter mode on this listing then the chess piece will come out very skinny :) )

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Re: Chess Pieces - Pawn

Post by halftonner » Tue 13 Feb , 2018 18:37 pm

Woooo ... had another go today with making the chess piece, and I found if I added a few extra lines of code so that the cuts were half as deep as originally specified and slowed the feed speed down a tiny touch, I have had success ... (though I couldn't do the reverse cuts as I've knocked off the tip of the tool and haven't got a spare atm)

I think I know why that helps (chip load etc), but I also know that there is a fine balance between cutting the material and just rubbing on the surface...

But I'm far happier :)

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