Calibration - digital scale?

Hi there

I was just wondering if anyone has used a digital calibration for their machines, similar to this one.


On at least one occasion, a user put a scale on their wasteboard, then tested how much pressure was necessary to make the belt skip a tooth — I thought that was an interesting technique to validate belt tension.

Over on the other side of the house (Inventables/X-Carve) a fair number of folks use luggage/fish scales to evaluate belt tension.

eh? I thought it told you how far the machine moved, not the force required?


My apologies, I completely misunderstood — in my defense, I picked Korean rather than Spanish when offered a language choice at the DLI-FLC.

If the device is accurate, it would be an interesting alternative to a dial indicator.

You’re a robot, admit it.

For that price it’s almost worth getting anyway…

save a couple more $ by going for a 150mm version.

With this in mind I should be able to calibrate my machine without using the circle square method? Whats the verdict @WillAdams

I have a similar DRO setup for my mini lathe and also considered the same for my XXL at one point. Then I realized that I could read “Machine Position” in CM4 as well as position relative to zero, so I forgot about adding the actual scales. TouchDRO is an Android app that connects via Bluetooth to the scales on for my lathe, so the output is on a small tablet. It appears to be pretty cool, however I bought the kit ages ago and have yet to install it(too busy playing SO3). Could easily be setup to run on an SO3 if you buy/cut to size the correct length scales.


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@cgallery some days, it would be easier.

@Luke — it would allow you to calibrate your machine’s movement in an idealized fashion divorced from the effects of cutting forces — I think it would be useful, but I still think for the best and most accurate calibration nothing beats a diamond-circle-square cut in the material one wishes to work in.

I think I will order one. Interesting. I never considered the point that you have made - the circle/square test should be done in the material you work with. I get the logic but between MDF and aluminium there would be a very different result I’d bet?

There seems to be some difference IME, mostly endmill deflection, but I’m terrible about using long, skinny endmills.

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I have ordered a 150mm one. I will see how I get on

I figured that to do an accurate calibration I would need to establish two points as far apart as possible and measure them very accurately. Although I am very happy with the accuracy of my 8" digital calipers i felt that I wanted to measure two points further apart.

I was debating the purchase of a 12" digital caliper when I realized I had a 36" iGaging scale on the shelf waiting to be installed on my lathe.

I used some magnets and clamps to jury rig the scale in place and it worked awesome.

Nice thing is that you don’t have to wonder if the error you are correcting is belt stretch or bit diameter.

My concern about the scales listed is that they are only 6" or 8", which is about the same size as a cheap digital caliper. I am not sure if they would be more accurate or faster than using a caliper.

If you don’t have a digital caliper then I would recommend the iGaging EZ Cal IP54. Build quality is excellent and the display is huge; even I can read it without my glasses. I have been using one for a couple of years and am delighted every time I pick it up.


wonderful, I can’t wait to get mine - something to do whilst waiting for CM to get sorted :smiley:

I stuck a dial indicator on a magnetic base, and used that against two points on the ends of the bed placed using a 1/2 inch “Standard”, and then a 10" “Standard” - and it worked quite nicely. The 1/2 inch standard got things calibrated close enough that the 10" was just a couple counts/mm of refinement. End result though was “pretty darn accurate” without needing a really long measuring tool. Temperature seems to have a fairly large effect on the belt stretch, so if your like me with the machine in my garage where it’s sometimes 30, sometimes 90, and more diligent than me, you’d calibrate a lot more often. (And for the curious, no, I don’t have a 10" micrometer, so I’m not really sure where my 10" Standard came from)

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