VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Alemite thread size for 1930

I removed the Alemite fittting on the front spring shackle and the threads were bad. I need to run a thread chaser in the shackle hole to clean them up. What size are the threads for a 1930 Model AD special sedan? The factory must have used another size in 1930 because it is not 1/4 NPT" or 1/8 NPT". I checked the old posts and did not find this information.

The fittings on my 29 spring shackles are 1/8" NPT. Your 30 has a slightly different configuration but should be the same size grease fitting unless it is an after market part that had something different

I suggest carefully measuring one of the good Alemite fittings from another part of the car to see what the thread is.

Measure outside diameter and get the threads per inch. Then, you'll know what the damaged one is supposed to be.

My '27 and '28 trucks have 1/8 NPT for the grease fittings. A couple of the Alemite fittings were damaged, but since the fitting was brass (the fitting was all boogered up - I suspect it was cross-threaded), the steel female threads on the truck were okay. They just needed to be chased with a tap.

I put some grease in the flutes of the tap to capture the brass shavings so they would not end up in the truck.

Let us know what you find.

Cheers, Dean

I was comparing my larger Alemite fitting with a
1/4-28 taper thread (SAE) fitting that I found
which wasn't on the car but is quite a bit smaller.
Perplexing because I never learned about pipe threads.

The diameter of my Alemite fitting is just a hair over
3/8" and I measured the threads to be 27/inch
with a slight taper so that should mean my fittings
are 1/8 NPT after all. I found a 1/8 NPT tap. Applying the grease to
to capture the metal pieces sounds like a good idea and I will
try it.

I am still a little confused about the difference between
NPT and NPTF.

Thanks for all the help.

Hello squeaky,
The two most common taper pipe threads used in the United States are NPT and NPTF. Applications range from electrical conduits and hand railings to high-pressure pipe lines that carry gas or caustic fluids. NPT threads are for mechanical or low-pressure air or fluid applications and require the use of sealing compounds like Teflon tape, to provide the seal. When the application is more critical, and the sealing compound may fail due to high heat or pressure, NPTF Dryseal threads are used. This mechanical seal is produced by the mating and slight crushing of the threads when a wrench is applied to tighten the fittings. This is copied from an online source. I think the F may stand for 'fuel'.

The "F" is for fine thread.

Thanks for all the info. I love this hobby and when I get enough experience I hope to help others.

The "F" stands for "Fuel", not "Fine Thread". See below for the various types:


NPT: National pipe taper. American National Standard Taper Pipe Thread. Tapered for sealing, often without any thread sealant; for connections in nearly every type of service.

NPS: National pipe straight. American National Standard Straight Pipe Thread. For rigidity; sealable only with sealant; sometimes male straight enclosed by female tapered for low-pressure sealing.

NPSC: National pipe straight…coupling. American National Standard Straight Pipe Thread for Couplings. For general couplings.

NPSF: National pipe straight…fuel. Dryseal USA (American) Standard Fuel Internal Straight Pipe Thread. Internal only, straight.

NPSH: National pipe straight…hose. American National Standard Straight Pipe Thread for hose couplings.

NPSI: National pipe straight…intermediate. Dryseal USA (American) Standard Intermediate Internal Straight Pipe Thread. Similar to NPSF but slightly larger; internal only, straight.

NPSL: National pipe straight…locknut. American National Standard Straight Pipe Thread for loose-fitting mechanical joints with locknuts.

NPSM: National pipe straight…mechanical. American National Standard Straight Pipe Thread for free-fitting mechanical joints for various rigid mechanical uses.

NPTF: National pipe taper…fuel. Dryseal USA (American) Standard Taper Pipe Thread. For dryseal connections in nearly every type of service, especially fuel connections.

NPTR: National pipe taper…railing. American National Standard Taper Pipe Thread for railing joints.

PTF-SAE SHORT: Pipe taper, fuel, SAE, short. Dryseal SAE Short Taper Pipe Thread. Named after SAE International; similar to NPTF but one turn shorter.

Wow, a ton of good info. Thanks Mr. Dog!

Dean

You are welcome!

In trying to restore as close as reasonably possible to original, how important is it to have alemite instead of zerk grease fittings? Right now my '32 has both, but the zerks were probably added over the years.

If you are going to have your car judged then you will need to install the original Alemite fittings.

I have some of the originals but not all. Available from Filling Station? Are they same as original?

No. They have a hex at the base of the fitting but that can be turned down on a lathe and then the fitting can be re-plated.

If you buy the 90 degree ones and remove the fitting from the base you have them without the hex. Check it out. It will cost you more but you will have correct fittings. Easier and cheaper then modifying and re-plating. You need a couple of 90s anyway and also at least two 30 or 45 degree for the front axle spindle. Not sure which right now.

UPDATE: Further to this I don't see the 90 degree with the plain fitting on their website anymore? You would probably need to contact them to see if they still offer it.
If you are going the route of turning them down and re-plating I have 18 new plain brass ones that would be a good candidate for that. PM me if interested.
The ones with the hex were used on Dodge Brothers in the 1920s so they are period correct but not what Chev used. I also have two lots of 20 of the nickel plated with the hex in case you just want to use them as are.

Thanks for the info and the offer. I will check with Filling Station to see what they have, and then decide what I am going to do. I guess if I use them with the hex, then I might as well just put zerks in because it won't be original anyway.

Even with the hex, they are far more cooler looking than the ugly zerks

Not sure if the zerk grease guns can handle the 600 weight oil used in most of the fittings. Might leak? I put some batches of used alemites on E-bay earlier.

The Zerk fittings are definitely ugly looking on the earlier vintage Chevrolets.

Cabboy: Prices on your alemite fittings?

Just completed rear end re-assembly There are grease fittings at each wheel bearing. I have packed the bearings with grease. Was 600W oil originally used here also?

There is actually a grease cup in the back of the axle housing on each side and not a grease fitting.

OK Thanks JD. Any source for these? Also, might there be a lubrication chart or diagram for a 1932 Chev chassis?

Try Gary Wallace for the grease cups. There is a lubrication chart in the Owner's Manual.

Thanks. Found the chart. Looks like most points call for SAE 160 oil. Grease cups at rear wheel bearings and water pump and distributor.
Do I need a special alemite gun? Is there a light enough cartridge grease available?