Thread: Large Hole Measurment

This is something I've had lying around for months ever since I read in here problems some were having measuring large holes.

It is something most should be able to make or "know someone that knows someone"

Take it as an idea as it can be changed depending on who would want one. it looks so simple I wouldn't be surprised if it didn't already exist but I've never seen one similar in my life.

http://www.f-m-s.dk/Large%20Hole%20Measurement.pdf

If anyone decides to have a go I'm sure we'd all like to see pictures.

Happy machining

Gordon

I have a device that fits a dial test indicator. It will measure holes from 0.5" up to 7.5". It's only real use is to compare a known ID to another ID.

I don't do a lot of large holes, but I usually reach for an inside mic to measure with.

Originally Posted by crashtestdummy

I have a device that fits a dial test indicator. It will measure holes from 0.5" up to 7.5". It's only real use is to compare a known ID to another ID.
I don't do a lot of large holes, but I usually reach for an inside mic to measure with.

That's the best adaptation of this kind of device that I've seen. It can be used for direct measurements both inside and outside by setting with a stack of gage blocks. You'll need to be sure that both of the contacts do not have flats on them. Flats can interfere with accurate readings.

Gene

You guys have never seen a Mueller Gage?

Mueller Gages Company - 2900 Series

A Mueller gage and a calibrated ring or disk is hard to beat. Dial bore gages are great too, but have a practical limit in diameter.

However, for the money, I don't think you can beat a tubular micrometer for large diameters. IMO, measuring small diameters is much harder.

http://www.use-enco.com/CGI/INSRIT?P...PMAKA=240-0035

Also, you really should be setting this thing with a gage block stack, not a height gage. Most height gages are only good for a few .001s.

You can also get ID blocks for use with gauge blocks. They won't do internal grooves like the Mueller Gage will.

Originally Posted by crashtestdummy
"I have a device that fits a dial test indicator. It will measure holes from 0.5" up to 7.5". It's only real use is to compare a known ID to another ID.
I don't do a lot of large holes, but I usually reach for an inside mic to measure with."

I looked at one of these awhile back to check the I.D.'s of some bores that were larger than our bore gages, but decided against it. The bores were 2" deep & I was concerned about checking for taper & bellmouth on the parts. Are longer extension tips available? I wound up building an indicator gage very similar to what Gordon posted in his link and used our jig grinder for the setting master. No pictures, though. (Sorry, Gordon)

Originally Posted by toolmaker35

Are longer extension tips available?

The tip on mine is just a machined set screw. It would be easy to make one longer, but the base is just aluminum, so there might be some flex issues with a longer tip.

Hi Gord,

It kind of looks like a dial bore gauge. They are made to measure up to 32"

http://www.mitutoyo.ca/files/c_section%20us-1001.pdf

I don't mean to dissuade you from making your own but I would think that making wheels on the bottom and having a rigid stick part would make it so you could move your tool in the bore to get a proper measurement. Not sure with your way that when you move your moving stick by hand would give you problems getting a proper size.

For deep bores on a lip I will quite often use a taper gauge

Gagemaker Catalog | Gagemaker Houston TX | Catalog, Holding, Left, Pages, Right | TDWIN Taper | API-Gauge | Gauges - Gagemaker Houston TX
page 24 of the general catalogue.

Mydrrin.

My OP was a suggestion. There's plenty of tools out there that can measure large diameters but mine should be easy to make and inexpensive.

There are also plenty of options for measuring small hole diameters and it's only a question of how much you are willing to pay and how accurate you need to be.

Hi Mydr

I've no intention of making one as I don't make anything with large holes. If you never have a problem measuring large holes then you are a lucky man

Gordon

The Sorenson Center-Mike was marketed for measuring holes or the distance between the walls of adjacent holes.

I've got one that uses a vernier to measure directly up to 7-1/2" and I've seen larger ones on Ebay. Mine came with a standard bar with two holes and a known distance between them




Mike

Originally Posted by Gordon B. Clarke

Hi Mydr

Good one Gord

{derisive response removed - trl}