How to use a Blake Coaxial Indicator

I need to use a Blake coaxial indicator to line up my spindle centerline with 4 holes in a transmission case. The holes are 3/8-16 and need to be bored out and then Heli Coils put in. The case is aluminum. Any tips on using the coaxial indicator would be appreciated. Thanks, Steve

Reply to
Sierevello
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I'd just insert a 5/16" drill bit or blank in the spindle and line move the part around until the bit goes down the hole with no effort at all. Tighten up the setup and away you go.

Pete Stanaitis

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Reply to
Pete & sheri

It won't do a very good job inside a threaded hole, and the feeler will pop into and out of the threads as it rotates.

What I would suggest doing is making a piece of steel on the lathe which is large enough to not drop through on one end (say 3/8" or

1/2"), and on the other side is turned to a diameter which just barely slips into the threaded holes. (Turn both diameters in a single chucking, so you know that they are concentric.) Then, use the Blake to monitor the OD of the upper end to check concentricity. That way, you have a smooth surface to read.

Good Luck, DoN.

Reply to
DoN. Nichols

Screw a clean bolt into a hole, leaving its smooth shaft outside. Then dial in that shaft using the Blake as normal. - GWE

Reply to
Grant Erwin

Not a good idea if he's after precision. A lot of bolts I've seen don't have the threads all that concentirc with the body of the bolt.

Doug White

Reply to
Doug White

A special-turned toolmakers button would do here. Simply turn the shank so it *just* barely drops into the threaded hole (so it picks up the tap drill diameter) and leave a larger section to indicate off of. I'd make it out of brass.

Jim

Reply to
jim rozen

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