I wasn't sure where to post this but I this is the forum I frequent the most. Also, this will be used for the all motor build I am doing so, here we go...

I was looking at stretch gauges online and was a little put off by the price. They seemed to be a very simple device but they cost around $60 for the cheapest. I decided to try my hand at making one myself. All I used was an old micrometer ($5 at a flea market), a dial indicator (Used the $10 one from Harbor), a spring, and a few nuts and bolts. I am going to ditch the harbor freight indicator and use the federal that I have. The Harbor freight indicator does not have very smooth movement it kind of jumps a little.



To build it all I did was...

• Cut the spindle off of the micrometer then drill out the rest of the material so the indicator could slide in.

• Then I drilled and tapped a hole for a set screw to hold the indicator in place.

• I used a spring to give it the added resistance it needed to keep its weight from affecting the reading. To hold the spring in place I used a washer between the tip of the indicator and the shank (not sure if that is the right term).



• On the other end I drilled a hole through the opposite side of the anvil then used a hammer and center punch to tap out the tip. (They are next to impossible to drill through)

• I then tapped that hole so that a bolt could be threaded into it.

• I found an appropriate sized bolt and sharpened it to a point on a bench grinder. (A little grinding of the micrometer was neccesary for the bolt head to fit.)



That's about it. Assemble it as shown above. Don't tighten the set screw too much because it will affect the reading of the dial indicator.

 

Very nice job.

 

Very creative!
Doesnt the dial indicator need to go to .0001" to be accurate enough?
Cant really see the indicator face that well...
nice job none the less!

 

Yes you are correct. Bolt stretch specs are usually given in ten thous. of an inch. The Federal gauge I'm going to use measures down to 5 ten thous. of an inch. The funny thing is the ARP gauge I got to use before was only in 5 thous. of an inch. Thanks for your input!

BTW: I'm also working on a DIY ring filer.

 

Good job thinking outside the box but, it looks to big to fit on the rod when its in a block. Have you checked for clearance?

 

Unfortunately I cant check the clearance on a block at the moment. My block is still at the shop having sleeves installed. I think it will be a tight fit and will probably have to sit at a 45* angle to the cranks centerline. You can see here in this picture there is a good deal of room between the rods and the block itself. Worse comes to worse I'll just have to take some material off of the micrometer.

EDIT: I think the pictures make it look bigger as well.