Longer stem for indicator

[3strucking]

My model is the 513-504, the model # is wrong in my op. I would like a longer contact point to reach inside a barrel without having to pre drill the chamber.

 

[GeneT45]

My model is the 513-504, the model # is wrong in my op. I would like a longer contact point to reach inside a barrel without having to pre drill the chamber.

That indicator with 2" tip from Long Island Indicators is exactly what I use to reach into a nascent barrel chamber and indicate the throat area. Depending on caliber you will probably still have to pre-bore or pre-drill as 2" won't get you to the throat by itself - you need to get some of the indicator body in there. I advocate boring at a taper matching your reamer body (but smaller, of course) - at that point you can dispense with bushings and the reamer can be held rigidly.

GsT

 

[IamNotImportant]

I have a Mitutoyo 513-403 indicator and I need a longer stem for it. I would like one that is 2” in length or close to it. I see some listed on Amazon, are they worth a try?

Mitutoyo 513-415-10H Dial Test Indicator 1.0mm Range, 0.01mm Graduation *SHOWROOM*

Item Description Range: 1.0mm Graduation: 0.01mm Dial Reading: 0-50-0 Basic set- H Set (additional stem) Performs easy and accurate measurement of narrow or recessed areas, plus inside and outside diameters that dial indicators cannot access No-clutch structure for automatic reversal of...

shop.idealprec.com

I know that it is "MM", but this is what i believe in the lines of what you are looking for yes?

 

[3strucking]

Mitutoyo 513-415-10H Dial Test Indicator 1.0mm Range, 0.01mm Graduation *SHOWROOM*

Item Description Range: 1.0mm Graduation: 0.01mm Dial Reading: 0-50-0 Basic set- H Set (additional stem) Performs easy and accurate measurement of narrow or recessed areas, plus inside and outside diameters that dial indicators cannot access No-clutch structure for automatic reversal of...

shop.idealprec.com

I know that it is "MM", but this is what i believe in the lines of what you are looking for yes?

I like the indicator I have, I just want a longer stylus. I will check with Long Island for the stylus.

 

[3strucking]

That indicator with 2" tip from Long Island Indicators is exactly what I use to reach into a nascent barrel chamber and indicate the throat area. Depending on caliber you will probably still have to pre-bore or pre-drill as 2" won't get you to the throat by itself - you need to get some of the indicator body in there. I advocate boring at a taper matching your reamer body (but smaller, of course) - at that point you can dispense with bushings and the reamer can be held rigidly.

GsT

I am new to chambering so I figured for my first one, I would let the reamer do all the cutting. I like the idea of removing the majority of material by boring and may try that.

 

[davidpbest]

I like the indicator I have, I just want a longer stylus. I will check with Long Island for the stylus.

The Mitutoyo 513-504 is calibrated for absolute reading accuracy with a tip that is exactly 0.60" long as illustrated in the extract from the Mitutoyo catalog page 16 shown below. I reiterate that if you put a longer probe on this indicator, it will no longer read accurately in an absolute sense. See the admonition from page 19 from the same Mitutoyo catalog. This is true for all brands of test indicators, not just Mitutoyo. If you want a test indicator with a longer probe that will accurately display absolute distances, you're going to need a different indicator, not just a longer probe.

 

[GeneT45]

The Mitutoyo 513-504 is calibrated for absolute reading accuracy with a tip that is exactly 0.60" long as illustrated in the extract from the Mitutoyo catalog page 16 shown below. I reiterate that if you put a longer probe on this indicator, it will no longer read accurately in an absolute sense. See the admonition from page 19 from the same Mitutoyo catalog. This is true for all brands of test indicators, not just Mitutoyo. If you want a test indicator with a longer probe that will accurately display absolute distances, you're going to need a different indicator, not just a longer probe.


View attachment 428508

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The '504 (and longer tip) are widely used for this purpose in large part because of its thin body which allows it to be partially inserted into the nascent chamber. The (reduced) resolution is still ample for the task.

GsT

 

[Liljoebrshooter]

For dialing in a barrel the resolution doesn't mean much. You just need to be as close to zero as possible.
And yes I have chambered a few barrels.
Joe

 

[ChazzC]

Interesting: I was surprised that Mitutoyo would use this method to remove the contact point, so I checked my DTI's (I have 8 that are functional and one that was dropped - thus the extras) and on all of them (with the exception of a $15 one), including the 513-118, there are flats on the contact point to facilitate using the supplied wrench to remove the point:






@3strucking How about making your own extension so you can read inside the bore with the contact point you already have? Taps & dies are available on Amazon, so all you need is some 3/32" (-ish: my contact point is 0.086"/2.18mm Ø) rod and a #54 (1.40mm) or #55 (1.32mm) drill bit, depending on the material (could be brass since the load would be small and any deflection would be minimal, but you can get 0.085" & 0.088" drill rod from McMaster). Per LMS's Tap & Clearance Drill Calculator:

 

[xr650rRider]

Gordy Gritters book lists MSCDirect part number 99046633 for a 2.675" tip and part number 06445464 for a 1.5" tip. Those are for a Mitutoyo 513-504 which he also lists the part number as 06249411. He says it comes with a 0.7" tip and I think mine did as well. We'll use the 0.6 tip in calculation below.

Link for 2.675" tip

It becomes less sensitive with longer tip and for the Mititoyo being .0001" indicator with .0002" accuracy, it becomes the ratio of 2.675/0.6 * .0002" or .00089" accuracy. The reading between tick marks would become approximately .00045". The springs are setup for the shorter tip, so you can't even say it's accurate to that level. But your using the indicator as a comparator, one land vs another. When it is bouncing in same spot from one groove to the next, you can't technically say it's exactly 0 or .0001" but everyone does.

I have the MItutoyo 513-504 and the longer tip but I use it with original tip as .0001" indicator. I much prefer the Interapid 312B-15 which is a .0005" indicator with .0005" accuracy and comes with a 2.675" tip. The Interapid has a larger face and it's easier to interpolate between the tick marks and you can truly dial in a barrel so that it indicates the groove to exact same spot all the way around.

**** update ******
This link on Mitutoyo website and scroll down to 513-504 lists the default contact tip as 18.7mm or 0.7362" in length.