rod bolt streeeetch gauge

rod · 09-22-2012, 10:22 PM

i am looking a two different fixtures. one from Proform looks like a piece of channel cut to width but is 10$ cheaper than the one from Jegs which has a nice built in handle [which would be nice because i am so shaky] and has a case. your thoughts, please
[ARP and some fancy tool place have them at 150$. which to me is pricy for a dial indicator and a piece of aluminum. so they are out]
also what type of wrench/socket set-up do you or can you use with this type of gauge?
thanks rod in AZ

Alan Roehrich · 09-22-2012, 10:43 PM

Rod, one of the most important things is the dial indicator, it needs to have a really strong spring, and the tip needs to have a small radius. The Proform piece is okay, but like all the inexpensive version, the dial indicator spring is weak.

I make sure mine repeats by taking it off and putting it back on several times, then use my regular socket for rod bolts on my torque wrench.

By the way, you can calculate the portion of a full turn needed to stretch a bolt correctly, using the number of turns per inch of the threads. If the bolt is 7/16" -20, for example, then it takes 20 turns to move an inch. So one turn is 0.050". That means 1/8 of a turn will give you about 0.006" of stretch. Use that to know about how far to turn the bolt to get the desired stretch, and to make sure the gauge is reading close to correct. If you had the bolt just seated, turned it 1/8 of a turn, and got 0.010" stretch, you know something is off.

Tom Goldman · 09-23-2012, 02:07 PM

Like Alan said the spring is the most important thing....without it consistant readings are impossible.
Some indicators have a external cap that can have a stiffer spring installed.
I prefer to use a point tip micrometer for rod bolts.
Altho it takes a little more time, the micrometer is more durable,and repeatable than the indicator...Most people just dont like having to read tenth's on a mic.,but I feel more comfortable with it than the dial.
You tend to develop a feel for a given bolts yeild relative to the ammount of pull and rotation you exert.

rod · 09-23-2012, 11:57 PM

thanks guys for your help. it is very hard to do things like this in this small town. anyone with a high dollar motor, bought it and knows nothings. the rest know even less.
rod in AZ.

Reed Granrt · 09-25-2012, 09:30 AM

Rod
What I have done to make it easier on pulling the nuts is purchase a good quality wrench and weld it onto a 24 inch long pipe. This way I can put the wrench on the bolt or nut, install the stretch gauge and pull the wrench and watch the stretch gauge as I pull it. This will keep you from removing the gauge so many times and is not as prone for mistakes. My pipe has one size of wrench on each end of the pipe that pretty well matches all sizes as there are most of the time only two size bolts or nuts. Also as you start the pull, you can make a fluid pull all the way to stretch and not pull and stop and measure. Good cheap county boy wrench, just looks crappy, like me.
reed

09-22-2012, 10:22 PM	#1
rod Member Join Date: Dec 2009 Location: Kingman, NW AZ. in the middle of the longest stretch of Route 66 Posts: 313 Likes: 0 Liked 20 Times in 15 Posts	rod bolt streeeetch gauge i am looking a two different fixtures. one from Proform looks like a piece of channel cut to width but is 10$ cheaper than the one from Jegs which has a nice built in handle [which would be nice because i am so shaky] and has a case. your thoughts, please [ARP and some fancy tool place have them at 150$. which to me is pricy for a dial indicator and a piece of aluminum. so they are out] also what type of wrench/socket set-up do you or can you use with this type of gauge? thanks rod in AZ

09-22-2012, 10:43 PM	#2
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,066 Likes: 1,487 Liked 1,630 Times in 378 Posts	Re: rod bolt streeeetch gauge Rod, one of the most important things is the dial indicator, it needs to have a really strong spring, and the tip needs to have a small radius. The Proform piece is okay, but like all the inexpensive version, the dial indicator spring is weak. I make sure mine repeats by taking it off and putting it back on several times, then use my regular socket for rod bolts on my torque wrench. By the way, you can calculate the portion of a full turn needed to stretch a bolt correctly, using the number of turns per inch of the threads. If the bolt is 7/16" -20, for example, then it takes 20 turns to move an inch. So one turn is 0.050". That means 1/8 of a turn will give you about 0.006" of stretch. Use that to know about how far to turn the bolt to get the desired stretch, and to make sure the gauge is reading close to correct. If you had the bolt just seated, turned it 1/8 of a turn, and got 0.010" stretch, you know something is off. __________________ Alan Roehrich 212A G/S Last edited by Alan Roehrich; 09-22-2012 at 10:53 PM.

09-23-2012, 02:07 PM	#3
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,468 Likes: 874 Liked 838 Times in 232 Posts	Re: rod bolt streeeetch gauge Like Alan said the spring is the most important thing....without it consistant readings are impossible. Some indicators have a external cap that can have a stiffer spring installed. I prefer to use a point tip micrometer for rod bolts. Altho it takes a little more time, the micrometer is more durable,and repeatable than the indicator...Most people just dont like having to read tenth's on a mic.,but I feel more comfortable with it than the dial. You tend to develop a feel for a given bolts yeild relative to the ammount of pull and rotation you exert. Attached Thumbnails __________________ Tom Goldman 1500 SG , 1506 STK

09-23-2012, 11:57 PM	#4
rod Member Join Date: Dec 2009 Location: Kingman, NW AZ. in the middle of the longest stretch of Route 66 Posts: 313 Likes: 0 Liked 20 Times in 15 Posts	Re: rod bolt streeeetch gauge thanks guys for your help. it is very hard to do things like this in this small town. anyone with a high dollar motor, bought it and knows nothings. the rest know even less. rod in AZ.

09-25-2012, 09:30 AM	#5
Reed Granrt Member Join Date: Jul 2011 Location: Murfreesboro, Tn Posts: 149 Likes: 0 Liked 1 Time in 1 Post	Re: rod bolt streeeetch gauge Rod What I have done to make it easier on pulling the nuts is purchase a good quality wrench and weld it onto a 24 inch long pipe. This way I can put the wrench on the bolt or nut, install the stretch gauge and pull the wrench and watch the stretch gauge as I pull it. This will keep you from removing the gauge so many times and is not as prone for mistakes. My pipe has one size of wrench on each end of the pipe that pretty well matches all sizes as there are most of the time only two size bolts or nuts. Also as you start the pull, you can make a fluid pull all the way to stretch and not pull and stop and measure. Good cheap county boy wrench, just looks crappy, like me. reed