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Multi-Purpose Bore Gauge?

projectnut

Stainless
Joined
Mar 4, 2006
Location
Wisconsin
As the title states I'm wondering if some of my Imperial bore gauges can also be used to accurately measure metric bores.
Last weekend I picked up 3 Takachiho Seiki bore gauges. Unlike my other bore gauges where the measuring head is integral to the tool these use an independent dial indicator. These like the others were designed for imperial measurements. That being said I was wondering if by interchanging the current imperial indicator with a metric indicator they could be used to measure metric bores. I realize I'd need to set them up using metric master ring gauges rather than imperial ones, but by making those changes I would think they should be capable of accurately measuring metric bores.

I realize the probes are in imperial lengths, but with the multitude included in each set I would think there would be some that would easily work in the metric world. Has anyone ventured down this path before, and if so, what were your results?
 

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Yes.
Size is size, whether it's imperial or metric. Set the gage to the size you want it to read and zero the dial. You don't need an imperial dial although that would help because it wouldn't tend confuse the user when adjusting the size of the bore but if you're cutting the bore to a zero on the dial then who cares if it's a metric dial or an imperial one.
 
All of my dial-type Mitutoyo and similar bore gages came with standard AGD dial indicators, so they are quite interchangeable with similar travel standard indicators, whatever the dial graduations or manufacturer. If you are using only one gage at a time, you only need one metric indicator to share on any of your gages. Or you could just use an electronic digital indicator and switch it to inches or mm as you wish.

Larry
 
They will work fine either way. The usual way is to convert the metric dimension to imperial. If you don't want to do that just get metric indicators and change the sizes on the table that shows which extension to use.
 
Yes, the dial indicator is only reading the movement of the probe, 1:1. What you set the zero at and whether you read that movement in inch or metric is completely up to you.
 
Thanks for your responses, everyone. I currently have 2 metric indicators that measure in .005mm increments and 2 that measure in .01mm increments. They all fit the "new to me" bore gauges. It looks like I'll have to find a few of the more common size metric ring gauges.

As one who grew up and worked with the imperial system on a daily basis, I've somewhat avoided metrics. However, with the use of imperial measurements declining, and the rise of metrics this old dog finally has to learn some new tricks. The mills and lathes all have imperial/metric readouts, so I'm set there. The Bridgeport even came with both metric and imperial dials from the factory. I used them for years before I finally went to a DRO. The DRO is much easier to read and more accurate.
Most of my measuring tools are still imperial and making the conversion either in my head or with a calculator is getting to be a PITA.
 
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Not necessarily. You can use a jig and have jo-block stackups to get your size
Yeah, I gave up hunting for appropriately sized ring gauges for each anvil in my bore gage boxes. (If I did production, I would buy the precise gauges needed without a 2nd thought, but I do mostly one-offs.) I finally bought a bore gage setting kit. Frankly all you need is a set of gage blocks and a couple of gage block accessory flats, but the setting kit adds a bit of convenience and I don't have to keep getting out the "real" gage block set.
 
For the time being I think I'll use the gauge blocks as suggested by Mtndew. In all probability the gauges will only be used a few times a year. When I went looking for ring gauges, I was a bit surprised at the prices. Most vendors are charging more for a single ring gauge than I paid for all 3 bore gauges.

I even took a look at what was available on eBay. In some cases, the prices seemed more reasonable, but I wasn't willing to guess at what I might need then wade through 22,000 postings.
 
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Yeah, I gave up hunting for appropriately sized ring gauges for each anvil in my bore gage boxes. (If I did production, I would buy the precise gauges needed without a 2nd thought, but I do mostly one-offs.) I finally bought a bore gage setting kit. Frankly all you need is a set of gage blocks and a couple of gage block accessory flats, but the setting kit adds a bit of convenience and I don't have to keep getting out the "real" gage block set.

Not necessarily. You can use a jig and have jo-block stackups to get your size.

What does this tool/jig look like - would someone please post an image or two or a link. Thanks.
 
My well used bore gage doesn't measure the same on a ring vs a block stack its about .0007 larger on a ring

If you ever needed to go (there) a ring is my first choice
 
My well used bore gage doesn't measure the same on a ring vs a block stack its about .0007 larger on a ring

If you ever needed to go (there) a ring is my first choice

That should not be possible unless you have a problem with your bore gage, like a probe with a small flat worn on it or poor centering. Generally those errors should cause it to read smaller on a ring gage though, not larger. Very odd. Are you just popping the bore gage into a fixture to use the gage block stack or are you canting and turning the gage to find the minimum on the dial?

Next question I'd have is do you trust the ring gage? And what about the gage blocks?
 
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Not gravity it's constant in vertical use.

Yes I know to scan for the small or large measurements when setting/reading a gage

My setting (fixture) is a old Ford/Johansen accessory set and the blocks are mostly old doall the only calibration I've done on them is to compare several stacks of the same height and I didn't see anything wrong except the 4" block is about .00005 short according to my Marr .00002 indicator.

My best guess is it's the lack of spring pressure from the centering feet when using the block stack as there is no surface for the feet to push on unlike the setting tool shown above
 








 
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