1/2 - 12 tap

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whateg0
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1/2 - 12 tap

Post by whateg0 » Mon Jun 25, 2018 2:22 am

I am making some knobs for a drill press. The handle shafts are there, but the knobs are missing. I measured the threads as 1/2"-12, which I find as a UNS size and also a Whitworth thread, but whatever. Looking on Ebay, I found several labeled 1/2 1/32 12, or some variation of that. I don't think the seller really knows what they are. What did that indicate? I'm not planning to buy one of those, but I'm curious.

Dave

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Re: 1/2 - 12 tap

Post by Harold_V » Mon Jun 25, 2018 3:33 am

The designation makes no sense to me, but I may not understand all there is to know.
Does the listing provide a picture?

H
Wise people talk because they have something to say. Fools talk because they have to say something.

chucketn
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Re: 1/2 - 12 tap

Post by chucketn » Mon Jun 25, 2018 8:38 am

whateg0 wrote:
Mon Jun 25, 2018 2:22 am
I measured the threads as 1/2"-12, which I find as a UNS size ...
Dave
I looked through my taps to see if I had one. No luck. I have several 1/2-13 (UNC) and 1/2-20 (UNF). They seem to be more common in the US. I would change the thread to 1/2-20. I would gladly loan you one...

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GlennW
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Re: 1/2 - 12 tap

Post by GlennW » Mon Jun 25, 2018 8:54 am

That is interesting...
Tap.jpg
I quickly rooted through my "Seventh Edition American Machinists Handbook", but nothing jumped out at me.

There were some locomotive and boiler taps that were 12 TPI, but they were tapered threads.

Didn't have much time to noodle with it right now though.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

whateg0
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Re: 1/2 - 12 tap

Post by whateg0 » Mon Jun 25, 2018 9:31 am

GlennW wrote:
Mon Jun 25, 2018 8:54 am
That is interesting...

Tap.jpg

I quickly rooted through my "Seventh Edition American Machinists Handbook", but nothing jumped out at me.

There were some locomotive and boiler taps that were 12 TPI, but they were tapered threads.

Didn't have much time to noodle with it right now though.
I wonder if that is the "1/32" is the amount of taper? I didn't see anything in my quick glance in Machinery's Handbook. It might be there somewhere, though.

whateg0
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Re: 1/2 - 12 tap

Post by whateg0 » Mon Jun 25, 2018 9:33 am

chucketn wrote:
Mon Jun 25, 2018 8:38 am
whateg0 wrote:
Mon Jun 25, 2018 2:22 am
I measured the threads as 1/2"-12, which I find as a UNS size ...
Dave
I looked through my taps to see if I had one. No luck. I have several 1/2-13 (UNC) and 1/2-20 (UNF). They seem to be more common in the US. I would change the thread to 1/2-20. I would gladly loan you one...
I've thought about it. 1/2-13 would be a piece of cake. Thanks for the offer, but I have all the NC and NF taps up to 1/2", well, from #2-50 up, anyway.

I could turn the outside thread for the shaft. It's not my machine, though, so I was trying to keep from making extra parts un-necessarily. That sounds like an odd thing for me to say!

Dave

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Re: 1/2 - 12 tap

Post by whateg0 » Mon Jun 25, 2018 9:35 am

Harold_V wrote:
Mon Jun 25, 2018 3:33 am
The designation makes no sense to me, but I may not understand all there is to know.
Does the listing provide a picture?

H
Glenn posted the only pic I saw that showed the stamping on the tap itself. The other descriptions weren't really helpful. I think the description of the tap Glenn posted a pic of did say something about a taper, but I had initially thought it was just a tapered tap, not a tap for a tapered thread. I might have been wrong in that.

Dave

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Frank Ford
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Re: 1/2 - 12 tap

Post by Frank Ford » Mon Jun 25, 2018 9:55 am

Victor Machinery, home of myriad tap sizes, lists a 1/2-12plug tap for $11.80

https://www.victornet.com/detail/TAST-1/2-12.html
Cheers,

Frank Ford

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GlennW
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Re: 1/2 - 12 tap

Post by GlennW » Mon Jun 25, 2018 10:10 am

The 12 TPI tapered taps I mentioned were described as 3/4" and 1-1/4" .taper per foot, so I didn't see any obvious correlation between that and the "1/32".

1/2"-12 used to be a fairly common thread a long time ago, but is pretty much obsolete these days.

Taps certainly aren't rare as many suppliers still sell them.
Glenn

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whateg0
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Re: 1/2 - 12 tap

Post by whateg0 » Mon Jun 25, 2018 10:14 am

Frank, I found one online last night and ordered it. I suppose since these knobs are being turned from Delrin, I could just grind a tool real quick. It only needs to last a couple of parts and being plastic, a chunk of 4142 would be just fine.

Glean, thanks. So, I guess that 1/32 thing still is a mystery. Seems they are a real thing as the ones I saw were from different manufacturers. I wonder if Greenfield customer service knows and would answer the question.

Dave

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GlennW
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Re: 1/2 - 12 tap

Post by GlennW » Mon Jun 25, 2018 10:38 am

whateg0 wrote:
Mon Jun 25, 2018 10:14 am
I wonder if Greenfield customer service knows and would answer the question.
Just make sure you ask to speak to the person that has worked there the longest!

I bought a piece of equipment that wasn't too old and called the manufacturer to ask a question about it. A woman answered and knew all about it and went on to tell me that is isn't made any more and what other models would use similar parts if I needed any.

I called back a couple of months later and spoke to someone else, and he told me they had never manufactured anything like that and that there was nobody there that would know anything about it...
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

whateg0
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Re: 1/2 - 12 tap

Post by whateg0 » Mon Jun 25, 2018 11:34 am

I ran into that last week! I emailed IR to find out the differences in a 2475 pump and the pump used on the FGT10 compressor. I have both and was trying to decide whether to fix the newer pump that needs a new rod bearing and probably new rods, or use the older but working FGT10's pump. From what I've read online, they have the same bore and stroke, but very different rpm ranges and of course, cfm. Somebody called me back and said he didn't know what pump was on the FGT10 but it was really old and the 2475 is newer. Yeah, I already knew one was older and one is newer. What are the technical differences? If they have the same bore and stroke, why the different specs elsewhere? He had no idea, but would be happy to sell me something. Not helpful at all.

I guess I see the same thing where I work. I've been here 19 years and know something about most of the models we've built in that time. I also know some about the stuff that's older than that. And if it's something I don't know, I'll try to find the answer for the customer. Other guys here will just say they don't know, have a nice day.

We had a customer call about one of our products and the guy who knows that box was out that day. So, another of the support guys answered the phone. Didn't know anything about that model, but told the customer it needed "part A". I overheard that part and asked if he was sure because older models used "part B". How old was the unit? The guy told me he didn't know and if the customer ordered the wrong part, he'd figure it out when he got it. WTF???? I found out who it was and called the customer back. He told me he didn't order it because it didn't sound like the right part and was glad I called him back to confirm that. Since we don't have the correct part, I walked him through how to get the thing working again using stuff that is available, and he was grateful. Maybe I'm just old.

Dave

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