Measuring tooling

[nicko17]

I'm new to this forum , i wasn't sure where to post this.

I'm looking at buying a magnetic base + indicator and something to measure precise I.D . I asked a fellow machinist on his thoughts and he said i shouldn't buy a cheap magnetic base because they always have problems with turning on/off , and the nobs break. For the indicator he said any would work since the cheap ones are just as good. My local tooling place has a STM indicator for about 25$ that seems good. I wasn't sure on a magnetic base , i'm wanting one that pivots at the base , i have found a few not to sure if they are any good though.

As for I.D , i was thinking of getting a micrometer for 0.2-1.2" holes , then possibly the next size for 1-2" holes. Then get a dial/digital bore gauge for 2-6" . I have used the I.D micrometers before , but i have never used a bore gauge. I'm wondering if they are very useful/accurate. I have seen dial ones on ebay for 50$ , probably pretty cheap. Local supply has the X-Tender digital one for 230$.

I'm looking for suggestions on what to get , thanks.

[jerseyTom]

How precise do you need your measurement to be? Within 0.001-0.002"? Within Around 0.0005"? 0.0001-0.0002" ?

[Geof]

Bore gauges can be very precise but they could be overkill if you are working to tolerances in the +/-0.001" region and they can be tedious to use because their range of measurement on each setting is not large.

Telescopic gauges can sometimes be the best initial choice because they can be used for a larger range, they can be less expensive because the actual measuring instrument is an outside micrometer. A possible disadvantage is that you have to develop a proper technique and feel to use them reliably; which is not a bad thing as it does instill careful work habits.

This wiki explains them both. http://en.wikipedia.org/wiki/Bore_gauge

[nicko17]

Originally Posted by jerseyTom How precise do you need your measurement to be? Within 0.001-0.002"? Within Around 0.0005"? 0.0001-0.0002" ?

It depends on the job , usually i have been just using a digital Verney to measure I.D 's . I want something that is more precise than that. 0.0005" (half a thou) would be good.

Bore gauges can be very precise but they could be overkill if you are working to tolerances in the +/-0.001" region and they can be tedious to use because their range of measurement on each setting is not large. Telescopic gauges can sometimes be the best initial choice because they can be used for a larger range, they can be less expensive because the actual measuring instrument is an outside micrometer. A possible disadvantage is that you have to develop a proper technique and feel to use them reliably; which is not a bad thing as it does instill careful work habits. This wiki explains them both. http://en.wikipedia.org/wiki/Bore_gauge

You might be right , cause it would take time to set up plus you would have to have a ring to set it exc...

I have seen Telescoping gauges , never used them thought. I always thought it would be hard to get an accurate reading with them , cause like you said if its not right its not going to work.

[Mcgyver]

Originally Posted by nicko17 usually i have been just using a digital Verney to measure I.D 's . .

you said you're a machinist but you don’t have telescoping gages and small hold gages and mics?

to start with, get yourself some external mics, small hole gages and telescoping gages. A mag base doesn’t come into measure ID, you'd use it to set an ID (or OD) running true in the 4 jaw for example. As Geof said, indicators are only useful for measure ID if you have a bore gage; leave that for later.

you can do almost as good a job as the dial bore gage by making stepped plug gages and measuring with a tenths micrometer. Not for production but good for a one of where you need a good fit.

Our timing is off, i just sold (cheap) some extra gages.....my preference is not to buy SPI or other offshore junk, buy quality brands usd. I saw a Helio mic (german stuff that makes Starrett and Mit look a little scruffy) sell recently for $14. Why buy the cheesy stuff when you can have the worlds best for the same money?

[JimPAC]

Where do you live nicko17? I'm here in Wichita KS and a person can find the best quality inspection gear for pawn shop prices. 6000 laid off aircraft workers = lots of pawn shop goodies.

I have to say Mcgyver's plug idea is good. While you make your go / nogo you can practice up on your measurement ability.

Study your machinist handbook (Bible) and follow the chapter on measurement! Any good machinist can do what a dial bore gauge can do by using their worn out old mic.s and hole gauges / with a known standard of course.

Develop your skill and improve your craft. Don't worry about any statements about being a Machinist!
They have been gone for a while now.

[nicko17]

Originally Posted by Mcgyver you said you're a machinist but you don’t have telescoping gages and small hold gages and mics? to start with, get yourself some external mics, small hole gages and telescoping gages. A mag base doesn’t come into measure ID, you'd use it to set an ID (or OD) running true in the 4 jaw for example. As Geof said, indicators are only useful for measure ID if you have a bore gage; leave that for later. you can do almost as good a job as the dial bore gage by making stepped plug gages and measuring with a tenths micrometer. Not for production but good for a one of where you need a good fit. Our timing is off, i just sold (cheap) some extra gages.....my preference is not to buy SPI or other offshore junk, buy quality brands usd. I saw a Helio mic (german stuff that makes Starrett and Mit look a little scruffy) sell recently for $14. Why buy the cheesy stuff when you can have the worlds best for the same money?

First off , i just started working as a machinist in the industry. I'm only 18 right now , just finished high school. I do have some tools of my own O.D mics/verneys , others i have borrowed or the schools. Also the mag base has nothing to do with measuring I.D , i need one for setting up on lathe.

Where do you live nicko17? I'm here in Wichita KS and a person can find the best quality inspection gear for pawn shop prices. 6000 laid off aircraft workers = lots of pawn shop goodies. I have to say Mcgyver's plug idea is good. While you make your go / nogo you can practice up on your measurement ability. Study your machinist handbook (Bible) and follow the chapter on measurement! Any good machinist can do what a dial bore gauge can do by using their worn out old mic.s and hole gauges / with a known standard of course. Develop your skill and improve your craft. Don't worry about any statements about being a Machinist! They have been gone for a while now.

I'm in Ontario Canada. We have alot of laid off people here too , thats a good idea actually. I have been checking out the classifieds for tools.

[Mcgyver]

hey, the 'machinist' stuff was because you said 'fellow machinists' so it was confusing when you were asking newbie Q's...being a machinist takes years and an apprenticeship and those that are don't appreciate those that aren't using the handle. I'm sure you meant no harm and it didn't bother me - I'm not a machinists either btw, so not my axe to grind, just giving you the heads up.......great deals on fleabay and the classifieds these days for sure, good luck with it

[Geof]

Originally Posted by Mcgyver ......being a machinist takes years and an apprenticeship and those that are don't appreciate those that aren't using the handle......

We will be magnanimous and forgive him.

[Mcgyver]

Geof, I am always very forgiving. I expect the same from others, I have a lot to be forgiven for (hope things are good out west).

[nicko17]

Originally Posted by Mcgyver hey, the 'machinist' stuff was because you said 'fellow machinists' so it was confusing when you were asking newbie Q's...being a machinist takes years and an apprenticeship and those that are don't appreciate those that aren't using the handle. I'm sure you meant no harm and it didn't bother me - I'm not a machinists either btw, so not my axe to grind, just giving you the heads up.......great deals on fleabay and the classifieds these days for sure, good luck with it

Ahh sorry , i didn't mean it in that way. I was just talking about someone i know who is a machinist. I'm only starting out in the industry area , i'm at the bottom , i get treated like it too.

Back on topic , i'm going to keep looking around for tools i need. Thanks for all the suggestions.

[Geof]

Don't let us scare you off.

The resource you have available here is too valuable to ignore just because some old, or not-so-old-, farts banter back and forth and take digs at you. Don't be afraid to ask questions and don't be afraid to question the answers you get and ask for clarification when needed.

And don't get upset if we hijack your threads, just pull us back on track occasionally. Life is serious but not all the time.