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I purchased the SM calipers a few weeks back to replace a broken set from Starrett (I think )... this is a 1/4” drill bit. Did I perhaps choose some setting with the SM ones that is adding a specific amount to the depth measurements or something?





I feel like I’m missing something obvious.

I know you can measure fret height with the notch, but I don’t think that’s what is happening here.

Brad


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I just noticed the depth rod sits at the top of the fret notch, so of course it is going to read weird. Do people zero this thing out each time reading depth?




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Yep, you have to zero it. No biggie as long as you don't forget to re-zero when you use the other end.

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Steve Smith
"Music is what feelings sound like"

Got it. OK, will commit it to memory.

Luckily I caught it, I was 100% sure the tuner bushing hole wasn’t deep enough just by eye. So I guess I can see 0.070 discrepancies in a hole. Such a useful skill.

Thanks, Steve.


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Just one of them things. It took me a while but I managed to train myself to verify the zero on calipers every time I pick them up.

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Steve Smith
"Music is what feelings sound like"

Only ever had one which doesn't need rezeroed.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Yes.


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Unfortunately, most makers will tell you this is an incorrect method of using the calipers. And old machinists don't bother doing that anyway because to get a true reading you need take the measurement from at least 2 frets at the same time. Which is why I use a depth gauge....
https://images.carid.com/starrett/products/449az-3r.jpg

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"Act your age, not your shoe size" - Prince

That would get sent back so fast in my shop.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

I have run into the stewmac difference between the rod and the caliper and have almost got burned. Luckily for me the error was enough for my eyes to see. I figured it had some handy purpose involving zeroing out fret height that I did not quite get. I do not use it anymore.

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http://www.Harvestmoonguitars.com

I (and probably most everyone here) have been using my calipers to measure fret height (and other stuff) for years. As most everyone knows, the problem with getting an accurate measurement that way is that the caliper must be perpendicular to the fretboard. I don't find that to be an issue but I have, on occasion, put a small square next to the caliper for what I thought were more critical measurements (not frets).

It appears that StewMac has tried to make it more foolproof assuming you have the caliper re-zeroed. I will stick with my standard 6" Mitutoyo.

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Steve Smith
"Music is what feelings sound like"

Oh, I see what they did. You zero the depth measurement against a flat surface, and then measure the fret height as a negative number. By having the depth stick able to retract "below zero", you can hold the notched end of the main bar against the fretboard with the fret in the notch and end of the depth stick against the top of the fret, guaranteeing that it's perfectly perpendicular to the fretboard surface. Terrible as a general purpose caliper, but for this particular task it's a clever solution.

Although in that closeup photo it doesn't look like the end of the depth stick is ground square, which would make it useless for anything. But you could grind it square yourself easily enough, since it's not synchronized to the other two measurements anyway.

Yes, an interesting approach which might cause as many problems as it solves. And I agree, doesn't look square.

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Steve Smith
"Music is what feelings sound like"

I'm just glad I know what to do. For a minute there I was questioning my life choices up to that point. I could not for the life of me figure out why the two measurements were different.

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