Need help--Depth Micrometer

[garthg]

I bought a new-to-me Starrett depth micrometer on ebay for use in re-shimming BMW motorcycle transmission bearings. I've never used a depth micrometer before.

Using it, zeroing it out and changing the depth rods seem obvious enough. But it came with some other parts the uses for which I have no idea. There are some small rods that look like nails, a spring, a set screw and another steel rod with a turned end. I don't know if these were for some specific purpose of the former owner, or if they're part of the micrometer set.

If anyone know, please advise. Thanks.

(Sorry for the giant phone pics, but the parts are very visible.)

 

[franzdom]

They are superfluous red herrings.

 

[DenisG]

I believe that the top knurled end cap unscrews to allow you to exchange the different depth rods provided in their sets.

 

[KMScott]

Your Depth Mic is a blade depth Mic but you know that, it is missing one blade since most come with three blades. 0 to 1 inch, 1 to 2 inch and 2 to 3 inch. The three pins ( Die Maker pins) and the rest of the stuff are not parts for your Depth mic. Some times older depth micrometers had small shims that nest against the shoulder to make up for small errors in rod lengths.

 

[garthg]

Your Depth Mic is a blade depth Mic but you know that, it is missing one blade since most come with three blades. 0 to 1 inch, 1 to 2 inch and 2 to 3 inch. The three pins ( Die Maker pins) and the rest of the stuff are not parts for your Depth mic. Some times older depth micrometers had small shims that nest against the shoulder to make up for small errors in rod lengths.

Thanks. I have all three rods. Just not shown in picture.

 

[davethorik]

I love depth mics I sort of have a problem. I have 4 sets. Lufkin 0-6, Lufkin 0-6 blade depth mics, Lufkin 0-3 with graduated 5" base, and Starrett 449 identical to yours.

The Starrett are my beaters but the Lufkin sets all have 4" or 5" bases, sometimes a narrow 2.5" base is nice. I got my 0-3 set for $20 but they're in rough shape. Plier marks. Worn threads, luckily there is an adjustment. The blade keeper doesn't work so the blades spin just like a regular depth mic unless you hold the blade still. Between these and the Lufkin blade depth mics I use them probably more than the rod style.

 

[garthg]

I love depth mics I sort of have a problem. I have 4 sets. Lufkin 0-6, Lufkin 0-6 blade depth mics, Lufkin 0-3 with graduated 5" base, and Starrett 449 identical to yours.

The Starrett are my beaters but the Lufkin sets all have 4" or 5" bases, sometimes a narrow 2.5" base is nice. I got my 0-3 set for $20 but they're in rough shape. Plier marks. Worn threads, luckily there is an adjustment. The blade keeper doesn't work so the blades spin just like a regular depth mic unless you hold the blade still. Between these and the Lufkin blade depth mics I use them probably more than the rod style.

Thanks. I didn't really know the difference, but I think the blade mic will be fine for my purposes. And I think it will be more than accurate enough for my purposes. I paid $23.

Also, since I'll be measuring differentials, it doesn't really matter for my purposes whether it zero's out accurately (although I think it does).

 

[ttpete]

Thanks. I didn't really know the difference, but I think the blade mic will be fine for my purposes. And I think it will be more than accurate enough for my purposes. I paid $23.

Also, since I'll be measuring differentials, it doesn't really matter for my purposes whether it zero's out accurately (although I think it does).

You might want to check the 2 and 3 inch rods. All it takes is a known good 123 block and a flat surface. They should be adjustable.

 

[garthg]

You might want to check the 2 and 3 inch rods. All it takes is a known good 123 block and a flat surface. They should be adjustable.

The rods are not individually adjustable, but the mic is. I do have the adjustment wrench.

Since I'm only going to be measuring the difference between bearing height and recess depth, I think the absolute number on the mic is not critical.

But thanks for your response.

 

[A_Pmech]

Those are likely shop brew rods to check a feature too small for the standard size rod.