Inspecting threads with double-lead Go, NoGo gages?

[Piper3T]

Hello,

I was wondering if somebody could help clear this up for me. I'm looking to purchase some ACME thread gages. Our prints do not state if it is single-lead or double-lead, but I am noticing a lot of gages I see are stated as double lead.

I assume our shop is going to make the parts single-lead since there is not a specific callout. Can I mix single lead parts with a double lead gage? Or vice versa?

The parts have become a standard product for us and we recently found our early run shop gages had worn beyond use. The volume of the product line has increased and makes purchasing gages a worthwhile expense, especially considering we sell these as spare parts.

Thank you

 

[Coadster32]

Short...no you cannot mix single and multiple lead gages/parts.

I am a bit confused on your question. You should already know what gages you have, especially if they are a standard product for your company. If not called out, gages would be single lead.

 

[Gordon B. Clarke]

Hello,

I was wondering if somebody could help clear this up for me. I'm looking to purchase some ACME thread gages. Our prints do not state if it is single-lead or double-lead, but I am noticing a lot of gages I see are stated as double lead.

I assume our shop is going to make the parts single-lead since there is not a specific callout. Can I mix single lead parts with a double lead gage? Or vice versa?

The parts have become a standard product for us and we recently found our early run shop gages had worn beyond use. The volume of the product line has increased and makes purchasing gages a worthwhile expense, especially considering we sell these as spare parts.

Thank you

What kind of "prints" do you have? Footprints?

Let me know EXACTLY what the "standard" thread or threads is or are and I'll tell you just about everything you need to know.

If you can't tell what you are wanting to make it's impossible to help. Single start and double start (any thread) are two very different things and are incompatible.

 

[Piper3T]

Our print just says 1/2-8 ACME-4G LEFT-HAND THD

The shop gages we were using were just in the tooling box. No marking besides the part number. Gages I see online, some say single lead, some say double lead.

 

[Coadster32]

Count the starts, leads, of thread on the face of the gage, and you'll know what you have.

 

[Gordon B. Clarke]

Our print just says 1/2-8 ACME-4G LEFT-HAND THD

The shop gages we were using were just in the tooling box. No marking besides the part number. Gages I see online, some say single lead, some say double lead.

I've got a strong feeling you know nothing about threads. Talk to someone in your company that does.

To order the gauge (plug or ring?) for the thread you mention then:

½"-8-ACME-4G-LH

You'd better get it right as it'll not only be expensive but almost certainly have to be made.

You can see below all the dimensions and tolerances for that particular thread.

 

[Gordon B. Clarke]

Something I'm sure should be cleared up. The gauges you are replacing, are they "home made" or bought? If bought what is on them should be correct.

How many gauges are you planning on buying? Both plug and ring?

If you could scan a couple of drawings (just the part stating the thread) this would help as probably most of us would know if the denomination was enough to make a correct purchase.

 

[Piper3T]

There's nothing else on the print related to the thread other than what I already posted.
I got the old shop made gages from the foreman, they are single lead. So we'll order or re-make as single lead.

Thanks.

 

[Gordon B. Clarke]

From the OP:
I was wondering if somebody could help clear this up for me. I'm looking to purchase some ACME thread gages. Our prints do not state if it is single-lead or double-lead, but I am noticing a lot of gages I see are stated as double lead.

I assume our shop is going to make the parts single-lead since there is not a specific callout. Can I mix single lead parts with a double lead gage? Or vice versa?

The parts have become a standard product for us and we recently found our early run shop gages had worn beyond use. The volume of the product line has increased and makes purchasing gages a worthwhile expense, especially considering we sell these as spare parts.

There's nothing else on the print related to the thread other than what I already posted.
I got the old shop made gages from the foreman, they are single lead. So we'll order or re-make as single lead.

Thanks.

Are you new to the job or is someone trying to get you fired?

I'm not trying to be impolite but I think you know very little about threads judging from the questions you ask. I'm also very much in doubt as to how many different ACME threads your company has. Only one or several? What you write certainly suggests several different.

The only sensible thing to do is to ask the designer to specify (and insist on a WRITTEN list) the threads necessary for buying/making gauges and then get the foreman to tell you which to order and which he thinks can be made in-house.

If any of the gauges are to be home made then you'll not only need to order the best raw material but also ask someone what you have to order to measure the home made gauges. If I was you I'd want as many bought gauges as possible assuming the parts are to be made to spec. You will though almost certainly run into higher prices than imagined plus, in several cases, lengthy delivery times.

Summation. As Purchase Manager your job is to buy what is necessary at the best price. It is not that you are have to figure out what should be bought and what can be made "in house". That'll bite you in the ass.

When you start buying it might be a good idea to also purchase ASME/ANSI B1.5 ACME SCREW THREADS and give it to whoever makes drawings.

I've never heard of this company but I can imagine they can give you an idea of price and delivery time when you know what to get. Making your own is not a good idea.

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