Thread gauging tips and tricks

[Zoeper]

Does anyone have any tricks of how to guage threads without fancy tools or go/no-go guages?

 

I've heard of the 3bar/wire method, but wondered if anyone uses it and if it's practical to do on the floor while cutting to make adjustments.

 

Is there an equivalent method for female threads?

 

What kind of tolarances do you use, and how much must you allow for when a part is going to be plated?

 

Any input much appreciated.

Thnx

Pieter

[Mike@Dive Lab Inc.]

you can try thread mics, easier than 3 wire

 

when it comes to plating there is many variables, depending on the desired thickness and type of plating and the tolerance of the threads

[Guest]

If you don't have access to thread mics or gages then I would say open the Machinery's Handbook get the thread sizes and tolerances and make the gaging you need.

 

If you're working for yourself or some small projects that'll work fine. If however, you are doing work for a customer then in most cases that just won't cut it.

 

As far as plating goes, I don't know that there is anykind of standard it depends on what the build-up of the plating is called for, then you adjust your sizes accordingly to per side build up.

[Zoeper]

OK I hear you on the ease of use, but the $300 Mic does not fall within budget. i have to use what i have available (an outside mic)

By the way.. how does the thread mic work? Does it measure in the bottom of the valey or against the sides like the wires?

p

[Zoeper]

John,

I checked out Machinary's Handbook, but my world is metric Any ideas of where to find the relavant tables for metric threads?

When you say that this method won't cut it in the real world, do you mean the cumbersome nature of it or a lack of acuracy?

[Guest]

quote:

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where to find the relavant tables for metric threads

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They are in there, look a liitle deeper

 

Lack of reliability, most customers want to know the gages you are using are calibrated to a standard.

[crazy^millman]

They make tips for Micrometer's so you do not have to get the Thread mic's. I have the thread mic's up to 4" with anvils and I have the tips for my 5" and 6" micrometers.

 

HTH

[Tim Simmermon]

+1 to John

 

unless you are a hobbyist, invest in thread inspection equipment. Pitch mics are your best bet for OD work. They measure the pitch diameter of the thread.

 

You've already invested in machines and Mastercam, why sel yourself short on the inspection end of it?

 

Search the internet for the Thread sizes. There is also software available to calculate the max, min and pitch dia of any thread.

[Zoeper]

Tim,

I've invested in two mic's.

I'm using MC at uni, and i use a machine that they left for dead in the basement.

Don't get me wrong.. i would love to get every tool in the catalog that is soggy with drewl by now, its just not happening tomorrow - or the day after...

[Tim Simmermon]

Well eventually you'll build a library of inspection tools, don't worry. You can try wires, they are cheaper than a mic. Try ebay for some tools. Used inspection tools isn't always the best but it will help you get started. The other option is to get a mating part from your customer. Start out large and then gradually reduce the offset until your customers part goes on smoothly.

[htm01]

http://www1.mscdirect.com/CGI/N2DRVSH

this is a cheaper way out than thread mics

[Mike@Dive Lab Inc.]

getting back to the plating, you will want to talk to the plating shop first. You will want to make sure they can hold a tolerance on the plating thickness also repeatability.They should be able to give you pointers on allowances. We do lots of plated threaded parts and it will all come down to the plater and their process. I have a full list of thread plating allowances for the majority of standard threads. I don't remember where I got it, but I'll do some research and see if I can find out.

 

Mike

[Zoeper]

Tried the link but get

"The MSC Part Number that you entered could not be located"

p

[htm01]

http://www1.mscdirect.com/CGI/NNSRIT?PMPXN...&PMT4NO=4332029

try this one

[Kevangel]

I also use thread triangles(similar to 3 wires)

[Zoeper]

Thanx for that link.

ordered a set.

any ideas about internal threads

[htm01]

plug gage either buy http://www1.mscdirect.com/CGI/NNSRIT?PMPXN...&PMT4NO=4337723

or make your own

[Zoeper]

I'll make my own as soon as i get my thread triangles!

[Zoeper]

sorry, hit he button twice - cant delete either

[DavidB]

Download this pricess software!! MEconsultant

 

Password: swiss

[ARP]

I know this sounds like a cop-out but depending on the size of the thread, can you just get the correct screw or nut so you have a reference point at least.

[Tim Simmermon]

We do that with some threads. We'll check with a pitch mic then double check with a nut. We use a nut or a customers mating part.

[Hymen]

Plating on threads is a bit trickier than just allowing for plate thickness. It is usually a bit thinner on threads than yur dia. If you actually draw it up and offset plate thickness it's nowhere near what you really get! especially with hard ano!

Just something that always comes up for me.