Mitutoyo 513-504 usable contact point length

[TaperPin]

This little guy showed up and as small as the dial is, it still makes me smile - makes me want to pull barrels and check every chamber in the neighborhood

The standard contact point is rather short so the Mitutoyo 1.75” 136013 point was ordered that’s roughly 3x the length and 3x less resolution. Without magnifiers on it should be possible to see the needle wiggle.

It didn’t hit me until just now that a huge advantage of the Interapid with 5-1/2” extra long point is, reaching in just as far as the Mitutoyo without having to first rough cut a hole for the nose. That has probably been brought up a dozen times, but all my brain registered was $$$ and ignored the rest. The outfit this was purchased from sent along an Interapid catalog - probably not a coincidence.

So my question is, with diminishing returns between length and resolution, what’s the practical length for the Mitutoyo contact point? The 1.75” version that was ordered seems like a safe bet, but if someone is having good results with a longer one that could be worked into the budget as well.

Eventually I’ll end up with the Interapid, but with the Mitutoyo in hand the next weakest link is a headstock issue to sort out.

 

[jackieschmidt]

Since I pre drill and then single point bore my chambers before reaming, I am able to, (after pre drilling), reach in to the throat area with the stylus to indicate where the throat will form.

That little Mitutoyo is my indicator of choice.

 

[LVLAaron]

+1 to what Jackie said. I love that little indicator... can't beat it for the price.

The interapid though... is like a swiss watch.

Here's both in action.

 

[LVLAaron]

I have and usually use the longer 1.75 inch point on the Mity. I have good eyes and the indicator is still tight... Get both... dial a part in with the long tip, and then change the tip out, and see how you did.

 

[TaperPin]

Since I pre drill and then single point bore my chambers before reaming, I am able to, (after pre drilling), reach in to the throat area with the stylus to indicate where the throat will form.

That little Mitutoyo is my indicator of choice.

That’s the technique I had in mind. I‘m probably over thinking things.

 

[TaperPin]

+1 to what Jackie said. I love that little indicator... can't beat it for the price.

The interapid though... is like a swiss watch.

Here's both in action.

Good video - thanks for showing it. Feeling better about the 1.75” tip already.

Yes, the price is very affordable. On Amazon I was somewhat concerned about a counterfeit Mitutoyo since some counterfeit digital calipers are out there, but on eBay one of the sellers also has a business repairing and calibrating measuring equipment and it seemed safer than ordering from SunshineHappyDayz3456.