Thread: noDRO free calculator

Few years ago I have acquired Sieg MJ9526 lathe/mill 3-in-1 machine.
I had no time to play with it until now. I just had an opportunity to
give it a try, as I needed to fabricate some custom connectors for
laser cooling. Soon I found it quite confusing to mentally translate
required travel distances to the amount of rotation of the handwheel
expressed in turns and steps.

To solve the problem, I have cobbled up small utility to do just that.
It takes the distance as input and displays number of turns and steps
necessary to move it there.

Since I had to cut some tapers, it also calculate taper angles and
length.

Also it attempt to address some shortcomings of this particular
machine.

Screenshot and software (as a zip file) attached.

It works well for me, so in hope that it may be useful for someone
else I am providing it here for download.

It is free, small, whole program consist of a single file 176kb in size.
It should run on any version of windows, dont need setup, does not
write anything to registry. The only other file it creates is a text log
file, for convenience of having record of performed calculations.

Since it was written for Sieg MJ9526, it can be used without any
change for Sieg C6 / X2 / Grizzly G0516 / AL-60 / Harbor Freight,
and similar. If you know of any other model that is compatatible
please let me know. If you would like to have it working with other
let me know too.

I have no background in metalworking, English is not my native
language, and I am not able to think in imperial units, so please let
me know if anything looks or behaves oddly, or simply does not make
sense. Feedbacks, comments, suggestions, are welcome.

Enjoy.



noDRO.zip

One important thing I should probably mention is that I have arbitrarily
applied compensation factor (.975) to carriage movement.

I have measured accuracy on all travel axis, and found that while all
other were more or less correct - carriage distance measured on dial
consistently lead to negative error (dial = 400mm, travel = 390mm) in
both directions.

Said correction is based on assumption that all machines based on
Sieg MJ9526 use same type of the leadscrew. I would appreciate
any feedback to prove my assumption wrong, or to confirm that
it really is the case.

Originally Posted by pjw

...
Said correction is based on assumption that all machines based on
Sieg MJ9526 use same type of the leadscrew. I would appreciate
any feedback to prove my assumption wrong, or to confirm that
it really is the case.

Though your approach is a clever way of solving a problem it suffers more inaccuracy than what most forum members will tolerate. You will find more response from the Chaski forums or other forums that use use light equipment. This forum seeks the nearest .0001" rather than the nearest 1/32". Best of luck.

Originally Posted by RDL

Though your approach is a clever way of solving a problem it suffers more inaccuracy than what most forum members will tolerate. You will find more response from the Chaski forums or other forums that use use light equipment. This forum seeks the nearest .0001" rather than the nearest 1/32". Best of luck.

RDL I would be very surprised if more that 5% of the Forum members routinely seek to machine to within .0001 or 2.5 microns! Perhaps you meant .001"?

Ah! Well, chasing tenths does not mean you catch them.

Thank you for your heads up, and for the tip about Chaski forums.
I will certainly follow your advice.

Regarding accuracy, I should probably point that out from the very
beginning that this utility was meant to not replace measurements
but only to complement it.

Taken my lack of experience in this field, I am likely missing something
obvious, so any pointers will be gratefully accepted.

The way I am normally using it, is that once I have reading giving me
required number of turns and steps - I progress my work to something
like one step before - then measure the workpiece, then progress the
cut, and re-measure, as needed.

Getting answer of number of turns and steps up front, gives me little
more confidence that I will not 'overshoot' the cut and ruin the
workpiece.

Talking about numbers. For Sieg MJ9526 (admittedly the only machine
I know), handwheels for the lathe have the following dials:

Carriage - 1div = 0.5mm or 0.0197" (40 div/turn)
Crossfeed - 1div = 0.025mm or 0.00098" (80 div/turn)
Compound - 1 div = 0.025mm or 0.00098" (40 div/turn)

While carriage resolution sucks comparing to others - it is still quite
easy for me to "eyeball" half or even third of it, which would give
0.25mm (0.00985") or 0.16mm (0.00656") - it is still a bit less than
1/32" or 0.794mm. For other dials, getting 0.001" accuracy seems
achievable quite easily.

I never had a need to go below 0.2mm accuracy, but if I had to -
would I need another, more expensive machine to do so ?

Originally Posted by pjw

Thank you for your heads up, and for the tip about Chaski forums.
I will certainly follow your advice. ...
I never had a need to go below 0.2mm accuracy, but if I had to -
would I need another, more expensive machine to do so ?

It is possible to do useful things within those tolerances but you will find the the lack of accuracy to be bad for your language especially when you are fitting parts within each other. Interference fits is another game as well. You can improve the accuracy by measuring the last several mm with clamped on indicators reading the movement of your Compound.

Other forums that are popular with Sieg owners:
Home Model Engine Machinist
SiegM2andGrizzlyG0516 : Sieg C6, M2, and Grizzly G0615
MadModder - Index

9x20Lathe Yahoo Group, which is targetted at the more generic, slightly smaller lathe, but has lots of discussions, much of it applicable to general lathe work on this hobby level lathe