Tips of the Trade

whydontu

I Tried, It Broke
Premium Member
Those pesky aluminum bits in the file teeth? Your nice sharp carbide scriber pops them out in one pass, just run it along the tooth gullet. Maybe even sharpens the file at the same time?
 

thestelster

Ultra Member
Premium Member
Often I have to dial in a finished part in the 4-jaw chuck. But if I was to use the standard dial indicator tip, it will leave a mark all the way around the part. I could pull back the indicator spindle, but that's a PITA. So I remove the indicator tip, and screw in a piece of Q-tip shaft. It's soft enough not to mar the finish, but also hard enough that there's very little give and gives reliable readings.
 

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Susquatch

Ultra Member
Moderator
Premium Member
Often I have to dial in a finished part in the 4-jaw chuck.

I've never really appreciated using a plunge style dial indicator for this kind of job EVEN when the surface isn't sensitive to marking. I almost always use a lever type dial test indicator for this task. They have only a tiny fraction of the force and the ball is usually replaceable with bigger or smaller ones. For centering, the exact deflection doesn't matter but the best way to use them is still to drag them along a tangent line from the part's OD. I've never experienced a part getting marked using an indicator that way. But I suppose it's still possible that it might mark something like polished aluminium.

Truth is that I didn't even own a regular plunge test indicator till 30 years ago or so.
 

Susquatch

Ultra Member
Moderator
Premium Member
For most work, you don't need one like this, but this is my goto dial test indicator. It's a well made very sensitive indicator that can even be reversed (although I have never had to).

For you, one of its many features that you will love is its barrel size. It will fit down inside the chamber of a 308 or 6BR to dial in a throat.


I sometimes use mine with a longer needle to reach further down a bore. This reduces the precision of the indicator but they are so sensitive that you can still dial in your work below a tenth by looking for tiny movement between the scale marks. According to Long Island Indicator Repair, the Tip Thread on the Mitutoyo and Interapid is 1.7mm-0.35 (Starrett is 4-48). But I see conflicting info all over the interweb. If anyone has better info, I'd love to hear about it. My tip selection includes:
- 1.7" (43mm) w 1.4 mm ball
- 2.75" w 0.75mm ball
- 1.2" w 2mm ball
- 0.6" w 0.4mm ball
- 0.6" w 2mm ball
- 0.6" w 3mm ball

Contact Points for Dial Test Indicator 2mm Carbide Ball Tips 44.5mm Long M1.6 Thread Mitutoyo 136013 https://a.co/d/5x0Y9Dc

Note the above link says M1.6, not 1.7. But I have one of these and it fits.... Go figure!
 
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