How to set up a dial bore gauge against bearing?

Hello,

I got small bore gauge (18-35 mm or so).Tried to set it with a micrometer. Fiddly at it's best and even tought I don't need exact reading (mike bearing, lock the mike and use it to set the gauge) I don't feel overly confident with it.

Is there a method or design to use a bearing as gauge block to set a bore gauge? Some kind of self made fixture?

Actually was thinking of this kind of combo, but its pain to clear it from customs:

Bore Setter

If I just could "clamp" a bearing and use it's OD to set the dial bore gauge, without too much complications. I did came up with a plan of making sort of clamp, using ground rods as guides, but this is not very unique need, therefore I'm missing something obivious or someone has allready come up with tested design.

Or is it just a matter of putting mike into a stand and use mike?

Pekka

Edited By David Clark 1 on 14/05/2012 12:08:10

Pekka,

I looked at the setting gauge you mentioned; it occured to me that you could achieve the same result using a conventional height gauge on a surface plate. With my gauges at least, the base of the scriber is at the gauged height. The only disadvantage would be the need to hold the height gauge down while adjusting the bore gauge; a lead weight might be useful.

David

Pekka,

If you don't have a height gauge, which is what I set my larger ones up with, just like the expensive bit of kit you are contemplating, then for smaller ones, like yours, I do set up with a micrometer.

It can get a bit fiddly with a mic, but that is the standard procedure for smaller bore gauges.

With a mic, all I do is set the lowest size of the gauge, and lock the mic up. Then move the probes between the two mic faces until it shows the lowest reading, then set the zero on the dial. Job done, you are ready to measure the bore.

John

It might help if you held the mike in a home made clamp/stand - perhaps made of wood so you don't damage the mike. That woulod leave both hands free to manage the bore gauge.

Thank you all,

I tried a mike and dial bore gauge against bearing and fitting needle bearing ring. I think I got hang on it, but I'm missing a lot of experience and confidence. Didn't have such luck with telecopic gauge, alot of feel and there must be certain technique involved.

I have a surface plate, but not any reasonable height measurement equpment. As David explained, there is certain amount force involved, mine has "centering" clips with surpricing strong spring. I think this would be my plan "B".

John, thank you. If mike works for you, I know that it should be good enough for me too. Need some more practice. Sorry, I don't get this part of your text "With a mic, all I do is set the lowest size of the gauge, and lock the mic up."

I think it's same drill I'm practising (please point out if I'm doing something less than gracefull way):

1) Mike out outer diameter of the bearing.

2) Lock mike carefully, when I'm happy with the feel with bearing race.

3) Raid the box of bore gauge anvills to get decent reading (measurement range is 3 mm).

4) "Zero" in reading of the dial. I noticed that it pays off to actualy clamp the mike and bezel...once the gauge slipped out of mike and my zero was off imediatelly.

On practice run I had set/checked before mike with 25.00 gage, mike reading come reassuring close to 28.00 mm. I think that actual reading errot here does not matter, because the same mike is used to set the bore gauge.

Now there is one detail, I have been wondering: What is acepted way of setting the bore gauge dial to account for a fit?

My first instict would be to deside the fit and account it zeroing the dial, when checking bore. "Zero" would be my goal and my target would be to limit my actions + or - side of it.

Then again, it might be easier to set bore gauge to zero and keep mental record how many division more or less relative to zero I'm aiming at. There are tolerance clips, but at closer fit things get crowded.

I'll be practising some more today, and I'm thinkking of building a simple clamp for the mike.

Pekka

When I need to produce a small accurate bore with a boring bar I usually find it best to make a plug gauge first with a lead diameter 0.002 smaller than the rest of it.The smaller diameter gives a good idea of how close I am to the finished size . Just thought I'd mension it as a useful tip to beginners!