I need a threaded plug to fill a threaded hole. It's approximately 3/4" in diameter and I believe it's got 18 threads per inch. No idea how else to describe it or size it. I've scoured the internets and can't really find any good info. They all start with NPT pipe size, which is based on sched. 40 pipe, which doesn't really apply here. I need a chart with the thread pitch diameter!
Are the threads tapered? You know, conical.
What are you trying to fill?
Could you get a thread pitch gauge from sears?: pictures here
Then measure the diameter vs pitch and order via internet or lowes accordingly?
I may be reaching, but I was guessing by your profile picture that you might be trying to do this: http://www.banzai-racing.com/S4_omp_bop_install.htm
914Driver wrote: Are the threads tapered? You know, conical.
Yeah, maybe not tapered. I think it might be M22 x 1.5 metric.
Calipers, thread pitch gauge, chart of thread sizes major/minor diameters. Then to to (GRM advertiser) Pegasus and order the plug you need. Don't forget the washer thingie.
The real fun comes when you finally figure out you're dealing with BSP or BSPT. (British Standard Pipe/Tapered). And did you guys know that a Toyota 4AGE fuel pressure sender or idiot light sender, the part that screws into the block, is BSPT?
Do you have a dial caliper?
What makes you think it's metric? What's the application?
M22 = 22 divided by 25.4 = .866
7/8" = .875 Very close, easy to cross up.
Dan
Okay. The following is purely hypothetical, but let's say someone wanted to plug the holes in an old AIR manifold with threaded plugs. Peak-to-peak on the threads is 1.5 mm or 18 TPI. The hex head is 7/8", Pitch diameter is just about exactly 3/4".
Hungary Bill wrote: What are you trying to fill? Could you get a thread pitch gauge from sears?: pictures here Then measure the diameter vs pitch and order via internet or lowes accordingly? I may be reaching, but I was guessing by your profile picture that you might be trying to do this: http://www.banzai-racing.com/S4_omp_bop_install.htm
If so he's looking for M10x12.5 20mm long.
I plugged a mitsu G54B manifold (non jet valve, non HLA head install) with a Canadian quarter once. Unscrewed the pipe fitting, dropped in the quarter and screwed the fitting back in with some copper silicone on the threads. there was a step in the manifold hole where the fitting screwed in. Seemed to work.
Maybe you could blank the hole off in a similar way?
Dr. Hess wrote: Calipers, thread pitch gauge, chart of thread sizes major/minor diameters. Then to to (GRM advertiser) Pegasus and order the plug you need. Don't forget the washer thingie. The real fun comes when you finally figure out you're dealing with BSP or BSPT. (British Standard Pipe/Tapered). And did you guys know that a Toyota 4AGE fuel pressure sender or idiot light sender, the part that screws into the block, is BSPT?
Japanese manufacturers use BSPT for their pipe threads. So it's not surprising to come across these on Japanese cars.
If I wanted to know if a thread was metric or not, I'd start with a pitch gauge. It'll either be an exact match or it won't. Once you know if you're dealing with metric or not, getting the diameter is pretty easy.
Is it a bolt or a screw? 
SVreX wrote: Is it a bolt or a screw?
Nearly had an aneurism when I saw this typed 
Edit-
I understand its a joke, but I typically do the resupply for all of our stainless fasteners, and the question gets so annoying. In my description of what I am looking for, it will become pretty clear if it is a bolt or a screw by the type of head on it. But they still ask anyways, just to piss me off. I'm going to go cry in my corner now 
Yeah, it's not Japanese. It pertains to my other vehicle, a spectacularly straight and rust-free 1985 Chevy C30 Dooley.
akamcfly wrote: I plugged a mitsu G54B manifold (non jet valve, non HLA head install) with a Canadian quarter once. Unscrewed the pipe fitting, dropped in the quarter and screwed the fitting back in with some copper silicone on the threads. there was a step in the manifold hole where the fitting screwed in. Seemed to work. Maybe you could blank the hole off in a similar way?
I don't think that's going to work. I got 6 of them out with a 6-point socket and a 1/2" drive breaker bar about 18" long. It wasn't easy. Two of them I rounded off. With a 6-point socket. Thankfully, I was able to get them out with a pipe wrench. So some of the fittings no longer resemble fittings.
Hungary Bill wrote: What are you trying to fill?
I expected a lot more racy comments or jokes after this.......
I'm gonna go out on a limb here and say it's 5/8"-18 Inverted Flare.
I tried the same thing that you are doing once and grabbed a 3/8" trans line that had IF fittings. The fittings threaded into the manifold and tightened up.
It's worth a shot.
M22 X 1.5 or 7/8 - 18? The only way to ensure a nice fit (these aren't interchagable) is to retap the hole with a larger known thread and plug accordingly. Go up 1/8".
Plan B: Turn something close and TIG it into location, bench smartly and it won't look like a plug.
Dan
In reply to HiTempguy:
Maybe you've missed something. Where you been?
Well, it's not metric. It falls between 1.5 and 1.25 on the thread pitch gage I have. If I match the thread to a bolt and literally count an inch of threads on the bolt, I come up with 18 TPI. So let's call it 3/4 x 18. Not dead sure on the diameter, it could be a tad bigger than that. I guess I'll hit Lowe's and the local parts stores and see what I can turn up.
Edit: Hey, somebody go to my garage and vote up my truck. It's getting no love, man.
Happy?
Needs flames.
In reply to 914Driver:
Yes, thank you! 
Flames, you say?
pete240z wrote:Hungary Bill wrote: What are you trying to fill?I expected a lot more racy comments or jokes after this.......
Me too 
I went to the local auto parts store and asked for a 1/2" pipe tap.
The guy sighed like I was an idiot, and asked if I wanted fine thread or coarse thread. I said "pipe thread."
He went out back, and returned with a 1/2" UNF, a 1/2" UNC, in both taper and plug, and one pipe tap.
"I'll take this pipe tap, thanks."
Generally I just drag said object into the hardware store and try everything in the aisle till I find the right one. I have a feeling your part may not be that portable....
914Driver wrote: Happy? Needs flames.
Subtle, like "Was that thing flamed?" kind of flames. It's gloss black right? Use gloss with a satin agent in it to do some flame out lines. Or Black Pearleacent tastefully headed aft, put a lick or two on the hips too.
Hey, that's just me, but I have enough going on here .....
Dan
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