Ideas for 3d printed part to measure between motors?

Yep. In my case about 4.5-5mm.

@madgrizzle is your machine dialed in the way you want it? I think you had said not yet.

I need to get some time, like @blurfl said, run a test with the stock chain pitch and then my adjusted chain pitch. I have been rushing to put in a patio before my son’s b-day which has stolen much of my Maslow time.

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From motor to motor, I measure 3048mm, then subtract the 40.4mm to get 3007.6mm. Compare that to my chain measurement of 3003.43mm for a difference of about 4.17mm… Not too bad.

And that’s just measurement with a regular tape measurer, by myself (which was hard because of the width of the machine) I could have easily been off by a 1/16th or so. I couldn’t exactly pull it tight either since nobody was holding the other side

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Maybe I am wrong but, because that distance is so critical to all of the other maths for the calibration, it seems like those two better be within a few tenths of a mm. If not, then there is either an issue with the encoder steps (I doubt this) or the chain pitch is slightly different than 6.35mm.

As I mentioned, I looked up the length tolerances for the #25 roller chain and it was -0.0% / +0.15% so these would be within spec. Your results are actually very similar to mine, I calculate a chain pitch closer to 6.359mm based on your numbers.

This might be a measurement we need to take. The user could measure from outside to outside of the motors and do the automatic motor spacing measurement then internal to GC it could compute the proper chain pitch. I will defer to @bar and the other folks that came up with the calibration routine to confirm it is worth adding.

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I had suggested on github that a calibration factor be added that, in essence, changes the chain pitch based upon what Maslow measures and what a user manually measures. I didn’t get a response, but you can manually do it as you have been. Obviously, if the chain pitch under normal operating conditions is not exactly 6.35 mm, then results will be better using the correct value (as long as the “correct” value is used during calibration).

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Sorry, I don’t get around on GitHub much. So it sounds like you covered this and the work around is pretty straight forward. Maybe on a light coding week it can be added :grin:

different approach to the same problem: Calibration.

I believe that this is now supported under advanced settings.

I agree that we should make it a part of the calibration sequence, but let’s give everyone a chance to catch their breath. It seems like 1.11 is a nice stable build, and let’s enjoy it for at least a week before we rock the boat

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Looks awesome! And nearly done. And I feel your pain on time constraints as my Maslow time is also being taken up by a project for my progeny…

Hoping to do some fun details with the Maslow

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Oh man I can think of so many cool details to add with Maslow!

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Please, feel free to suggest. I have plans for gears to play with, a design for a rotating periscope (to look under the deck), some decorative ideas, etc., but I am always on the lookout for fun ideas to try.

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I have yet to get my Maslow up and running, but, unless I’m misunderstanding, it seems that you could 3D print a little “shelf” for a laser distance meter, that would hit an identical (but mirror image) shelf on the other side. Another advantage of this is that it could be used to get the top sprocket exactly at 12 o’clock with respect to the other sprocket. (getting the laser to hit the corresponding point on the other side would be very accurate alignment)

It would slide over the sprocket like a socket wrench over a nut. The left shelf would look like an “L” as you looked straight on, with the vertical at the centerline of the sproket. (right shelf would be a mirror image)

I have one of those laser distance measuring devices, and they are very accurate!

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how accurate? you would be looking to get an accurate measurement to ~0.001" and
you have to mount your marks at least that accurately, or you are wasting it.

how about 0.01 degree? see: Auto-Calibration Mods?

Earlier today I asked myself the same question. My Bosh acts like it’s accurate to 1mm… which perhaps isn’t good enough? I say ‘acts’ because when I put it on a solid surface and point it at a wall, it holds a reading, then when I slowly move it, it changes appropriately. I didn’t measure anything of a known length though… but I’ve used it to measure, marked with a tape measure, and things are usually perfect to within operator error. I can get you the model number later if you are curious.

take a look at https://www.youtube.com/watch?v=USa3HFLnrlk

with a metric tape measure, you should be able to get to .5mm, and possibly even
.25mm accuracy accuracy. It’s just a matter of what you measure against, and
measuring outside of motor to outside of motor seems pretty solid. measuing with
the laser would require you mounting some bracket one one side to bounce the
laser off of and on the other side line the laser up against something. I think
the variability in those too points is going to be worse than your accuracy.

If you have a laser, go ahead and use it, but we are primarily looking for what
we can do to get the motor-motor measurement more accurate for the
run-of-the-mill maslow user who doesn’t have a laser.

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You’d be positioning a laser dot onto a target just under 10 feet away. Doing an arc tan or arc sin approximation, I’m getting ~0.06 degrees. Assuming 1/8 inch in 10 feet… Tan-1(1/960)

lasers are like $3 now… nbd.

that’s why I linked a much more accurate chip, (in the video).

no idea if the claims are true, but it sure sounds like something we could take a look at if we worked out a method of calibration.

a $300 Leica laser is claiming an accuracy of 1/16" or about 1.6mm

we do substantially better than that with a tape measure.
https://lasers.leica-geosystems.com/disto/e7400x?c1=GAW_SE_NW&source=PLA_USA&cr2=USA__-__Leica____PLA&kw=788472&cr6=pla&cr7=c&gclid=EAIaIQobChMIoL6xopPF2gIVgf5kCh2SZggyEAYYBiABEgLFYfD_BwE

looking at granger https://www.grainger.com/category/distance-meters/distance-measuring-tools/measuring-and-layout-tools/tools/ecatalog/N-15y1
the accuracy ranges from 1/8 to 1/16"