Oldsragger

Hello, i will make a tool to use when i will mounting a pulley on a steering servo pump, so i need a threaded rod in correctly size that will fit in a steering servo crank, i have tested a bolt that fit, but i don`t know what size it is..i can only see 8.8 on the head of this bolt on the picture...i use a tool to find the size..but i can`t understand it.. it just a number on 16. watch the picture..

So i need help to find what you U.S people call it, that i can order on ebay or something,cause i don`t know what size i should search for.

thanks


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RandyS

Hi, we will also need to know the diameter of the bolt.

Oldsragger

Ok i will try to find out.

joe_padavano

Your first problem is that "8.8" is the strength indicator, and that means that it's a METRIC bolt, not SAE. The thread gauge you are using is SAE and the "16" means 16 threads per inch. Most metric and SAE threads are very close in pitch, since both are driven by the loads. Get a metic pitch gauge for this bolt, or better yet, take the bolt to a hardware store, find a nut that fits on it, and buy the threaded rod that also fits this nut. By the way, you don't need threaded rod. Most rebuilt PS pumps with the press-on pulleys come with a longer bolt, nut, and washer that is used to reinstall the pulley.

By the way, metric threads are specified like M8-1.0, where M8 = the fastener diameter in mm and 1.0 = the thread pitch (distance from one thread peak to the next) also in mm. SAE threads are specified like 1/4-20, where 1/4 is the diameter in inches and 20 is the threads per inch (TPI). If you take 1 divided by TPI, you get pitch in inches. Multiply by 25.4 to get pitch in mm. In your case, the 16 threads per inch is a pitch of 1/16=0.0625 inches=1.59mm. That's probably a 1.5mm pitch in reality. It's probably an M10-1.5 thread, which is a standard metric coarse thread fastener.

Oldsragger

Ok thats a good beginning, i will try my metric tool then and see what i will find out,i will add a new pics. btw, this is the orginal bolt that fit in the steering servopump in front holes. when i order the new overhauled steeringpump i got non threaded rod,washer and nut :/ so thats why i must made one self.

Do you remember that bolt i install with a nut and washer in the small steering pump bracket in the side of the engine block? that was a M10 bolt, but that was to big for the crankshaft hole in the steering pump, so maybe its a M8.. or M9 ? i will try the metric tool first on the bolt.

Oldsragger

Ok im back, and now i have checked the bolt with the metric tool,but non of them does not fit :/ only the "16" blade from SAE tool, on top of the bolt it stand HB UNC 8.8 hmm ..but,i found a nut that fit,and can help me to see if the local store have something that fit..but i think they have only short bolts.. my plan was to order this type on ebay or something.. just have to find out the right size first.

http://www.ebay.com/itm/Stainless-St...item35c5e6471f

Here is some pics again


To the left: METRIC ,to the right SAE

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The metric 1.5 shows the nearest on the metric tool that almost fit.

IMG_20130917_233403_zps27d0d491.jpg

The diameter on bolt

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"BH 8.8 UNC"

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MDchanic

Could this be an '80s bastardized part-metric, part-American fastener from the bad old mix-and-match days?

That caliper reads 9.4mm, which is 0.370", which is just under 3/8", so 3/8-16 seems like a likely candidate here.

What size is the bolt head?

- Eric

Oldsragger

Oh ok,maybe that, hm i think it was 15mm bolt head,maybe 13mm, but i can check it tomorrow for sure.

MDchanic

During the 1970s, the US government tried to switch us over to the metric system.
Metric measurements were taught in the schools, and labels and signs were required to be in metric numbers as well as American.
There was supposed to be a date after which it was illegal to use American measurements, but before that could occur, there was a large backlash against the program, and by the early eighties, it had all been swept away (after all, metric measurements had been used by the *****, and were still used by the Communists).
Manufacturers are still required to list metric measurements on labels, but they are free to use the traditional system as well, and often when they try to go "all-metric" the customers refuse to buy the product (with the notable exception of the 2-liter soda bottles, I guess because 2 liters is more soda than 64 ounces).

Around when all of this was happening, the American auto makers began to switch from American to metric, but they were not able to make the change all at once, so there were many years (including my 1990 GMC pickup truck) when you could find both metric and American fasteners together on the same car, necessitating the use of two separate sets of tools for any job you might need to do.

A metric-head fastener with an American thread would make sense (by the twisted logic of the time), as it would allow you to use a metric wrench to remove it, but would avoid GM actually needing to change the thread of the pump that it made.

I have not had to work on a late-'70s-early-'80s car in many years, though (and I never want to again, if I can avoid it), so others could probably shed more light on this than I can.

- Eric

joe_padavano

Well, ya got me. The "8.8" is definitely a metric bolt strength marking (about equivalent to Grade 5). The UNC is definitely an SAE marking for Unified National Coarse thread. This fastener is confused.

Oldsragger

That was quite a story,i didn`t know that. but ok thanks for the tip anyway

Oldsragger

Hm ok, well i will try to search a little what the marked can have for me.

Iv got a nut that fit so i will try diffrent types.

rustyroger

The French are the ones to blame Eric, The 1789 revolution ushered in the metric standard.
No bad thing, up until then units of measurement depended on where you were, remember pecks, grains, roods, bushels, hundredweights etc?.
The metric system was simple, and a gram or a meter was the same wherever you were, and it could be checked against a standard kept in Paris.
Can't blame the Communists or ***** for that.

International travel would be a nightmare if different nations decided they wouldn't use the accepted latitude and longitude standard because of anti British sentiments.

None of this helps Seff of course. I think Joe has identified the problem.
I think he has identified the thread he needs, so get a fastener of the correct size and use a wrench that fits the head. It doesn't really matter if it's metric or unified, or even a Torx or Allen head unless it's for a numbers matching restoration.

Seff, I have a number of nuts and bolts from various mid '70s American cars, if you let me know exactly what you need and I have one I'll send it to you. My fee will be "Thank you" and a picture on this forum.

Roger.

MDchanic

To the average American, the French are even worse.



Funny you should mention that, because originally there were two competing latitude and longitude systems, one centered in Greenwich, and the other centered in Paris.

The English one won out, and the French one is now all but forgotten.

- Eric

TripDeuces

UNC stands for unified coarse, which is your thread type. What you have is a 3/8 x 16 SAE coarse thread bolt. I don't think that is 8.8 but rather 88. (No idea what that means) The fact that your thread count/pitch gauges only fit the '16' indicates this.

oldcutlass

You have 3/8-16 x (length from under the head to bolt end in inches) flange bolt.

Octania

Looks like this is settled.
I have all manner of stuff that would do what you need, and if the above guy does not work out, I can help.

One other possibility that might work, if you have a SAE & Metric tap & die set, would be to get a bolt that is close- M10-1.5 - and has enough threads for your purpose... and just re-thread the tip for oh 20mm or so, to the desired 3/8-16 NC - enough to enter and hold in the pump shaft. Then use the remainder of the bolt, with a mating M10 nut and washer, to force the pulley on. Use the strongest bolt you can find, like 12.9 grade. Avoid stainless steel- it is generally weaker than carbon steel, and tends to gall and seize, which is just more headaches.

Here is a GREAT summary of standard bolt grade markings:
http://www.boltdepot.com/fastener-in...ade-chart.aspx

Oldsragger

Ok thankyou very much for good help! i will try to find 3/8 - 16 x something in ok quality

Oldsragger

Have found what i need now, just have to find a big heavyduty washer or something,and weld the threaded little bolt in the center of the big, hope it`s long enought.

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