How to do this dial indicator measurement?

[discotwo]

Attached screenshot from the manual I am working on. Steps 25-30

The purpose of this measurement is to get the difference in height between the gage block (LRT-41-014/3) and the bearing track. I have the special tools, but I do not have the DTI gauge L-bracket thats pictured. I have a regular magnetic base stand and indicator.

I understand the concept of zeroing the gauge on the block, but in order to get the measurement on the bearing track, I have to move the dial indicator. How do you do this without losing accuracy? From the manual, I'm assuming they loosen the bolt that holds the L-bracket to the pillar, and then 'swing it over'. I can't find any indicator stand that works like this, i.e. allows you to move the stand on the x-axis, as opposed to moving the part being measured.

Do I need another stand to do this? If so.... which one? I've searched Mcmaster and other sites but coming up blank.

 

[larry_g]

Your magnetic stand should do the job for you IF the reference surface it is fixed to is flat and coplaner to the bearing your measuring. I have also in measurements like this set a strait edge across the gauge block and used feeler gauges to measure the gap, If the bearing is to be lower than the gauge surface. Just how accurate do you have to be? a couple a thou or 10 thou?

lg
no neat sig line

 

[discotwo]

That's a good idea with the feeler gauges. I need to be accurate to 2 thou in order to choose the right shim.

Attached picture of the stand I have. Ordered it yesterday so I haven't tried it out yet. My concern is if I loosen the clamp to move the indicator horizontally, the indicator can also move vertically and throw off my measurements?

 

[larry_g]

You don't loosen any of the snugs. You release the magnet and gently slide the base around till the probe is in the correct position and reset the magnet to ON. You may be able to do it without turning on the magnet, just hold it down with hand pressure.

If you watch this at about the 9 minute mark you can see how to slide an indicator/base around on a surface to determine the change in another. In your case the housing is the base you slide along and the bearing is the unknown.

lg
no neat sig line

 

[matt_i]

You could fabricate that in the shop. It doesn't need to be super-precise, just solid...and...have match-marks so the tube doesn't rotate relative to the arm.

Consider the case where you have a 5 degree slope on the top end of the tube. It will measure the same theoretical reading as long as the arm is clocked in the same position relative to the tube.

Also consider cases where the L-bracket is bent at 87 degrees. Once again, as long as it is oriented in the same clocking to the arm, it will read the same position as its swung thru a circle about the center bolt.

Its roughly analogous to tramming the head on a milling machine, which is using an arm-mounted DTI to sweep out a circle on the mill's table as the spindle is rotated by hand. When the indicator reads the same all over the spindle axis is square/perpendicular to the table. Bottom line is the part that connects the spindle to the DTI can be egg shaped out-of-round, bent to a funny angle, the only requirement is that its solid (without deflection of the structure) and doesn't slip in the chuck....

I wouldn't worry about zeroing the indicator on the gage block, just note its reading and compare with the bearing track.

 

[Qrazy]

You don't loosen any of the snugs. You release the magnet and gently slide the base around till the probe is in the correct position and reset the magnet to ON. You may be able to do it without turning on the magnet, just hold it down with hand pressure.

If you watch this at about the 9 minute mark you can see how to slide an indicator/base around on a surface to determine the change in another. In your case the housing is the base you slide along and the bearing is the unknown.

lg
no neat sig line

As in the 9 minute mark, a small surface gage should do the trick. Make sure the surface is clean and take your time.

 

[joe49]

Make 2 gauge blocks maybe .010 longer than the needed height. Place straight edge across blocks and use feeler gauge to measure. The rest is math.

 

[Capt Chrysler]

What are you working on?

As I can't see the photo very well on my phone.

Capt. Chrysler

 

[discotwo]

@ Capt: It's a LT230 transfer case for a Land rover discovery 2. I'm rebuilding it with a center diff lock, taller gears, new bearings.

Thanks everyone. Making progress. Attached a photo. Since the transfer case is aluminum, I couldn't use the magnetic base, but I got lucky and the bolt holes in the housing matched the indicator pole (M8), but this means that I moved the indicator arm to get the readings.

Original shim was 0.105 inches
According to my calculations the new shim should be 0.084 inches.

Hmm, most of the components are being re-used, but I suppose new bearings and one gear could account for the decrease? If anything I'd have thought the shim size would go up though.

I got about the same measurement doing the feeler gauge and straight edge.

I'm going to keep measuring and see what I get

 

[larry_g]

@ . Since the transfer case is aluminum, I couldn't use the magnetic base, but I got lucky and the bolt holes in the housing matched the indicator pole (M8), but this means that I moved the indicator arm to get the readings.

I would suggest that you us the mag base and just hold the base against the case by hand.

lg
no neat sig line

 

[APEowner]

I would suggest that you us the mag base and just hold the base against the case by hand.

lg
no neat sig line

I'd connect the mag base to a 123 block or something similar and hold that to the case by hand.

 

[discotwo]

I would suggest that you us the mag base and just hold the base against the case by hand.

lg
no neat sig line

Good point, I did this. Worked out well. All assembled, and no play in the center differential.

Made a quick video for my friends on the land rover forums