View Full Version : Carb Spigot Threads

12-29-2006, 05:56 PM
My repo carb spigot nuts for my '52 Chief seem to be a tad tight. Got one on OK, but can only get the other to go about 2/3 of a turn. (No, it is not cross threaded).The old ones go on just fine. I've tried to deburr the nut threads,wire brush them with a Dremel, wire brush the cast iron spigot threads and have made liberal use of Tapmagic, but seem to be stuck. Anybody got any ideas? I'm thinking maybe I'll just buy a few more and hopefully get one that fits better.

T. Cotten
12-29-2006, 09:30 PM

Please inform the vendor of your sticky one of your concern, as they will want to know! Most likely you will receive another.

If you intend to buy another set, then I suggest http://www.jerrygreersengineering.com/
I have gone through a couple of dozen of theirs without a problem, and the cad is immaculate.


12-30-2006, 09:03 AM
Thanks, Cotten. I will have to go through mt records to see who I bought them from.

T. Cotten
12-30-2006, 09:36 AM

Please note above that I suggested informing the vendor, not the forum!

Vendors need to know when there might be a problem with a run of parts; It happens to the best of them.


12-30-2006, 09:53 AM
I agree with Cotten, but ????, with some manufacturers, poor quality is the norm. With this type of shady vendor, we the consumer, are intentionally, the testing zone, for product quality control. Paps

T. Cotten
12-30-2006, 10:11 AM

If the vendor refuses to make good on a problem, then that's 'news'.

Otherwise, I have encountered a great variety of Chief manifold nuts as part of my reconditioning service, and the inside diameter can vary from vendor to vendor just as the conformity and finish. The worst were black oxide that take a 2" wrench, but most were serviceable.
Many vendors are middlemen, and might not be aware unless we notify them. And the vendor might not be on this forum to defend himself.


12-30-2006, 10:39 AM
Again I agree with you. Notice, I have not mentioned any particular vendor ? I only refrain from naming any because they either can't, or they refuse, to fess up, when such an accusation is made. Overall, vendors and consumers get the raw end of the deal. The shady manufacturers are whom I speak of. They know whom they are. Vendors are part of that quality control system I spoke of. Just as the end user, the vendor gets bitten too. It is so refreshing when a vendor tells me that he can supply several different manufactured parts. It is even more refreshing when he tells me which ones to avoid. How did he learn this knowledge ? The hard way ! Sure.........the shady manufacturer [notice the term "shady Manufacturer"] excepted a return on the faulty parts [the vendor or consumer paid the return shipping] but the next batch was just as faulty. Thank goodness for the vendor section here on this forum. At least there you can get a better idea of where not to buy and where it is safe to buy. I got this topic off in the wrong direction and I appologize. Darn faulty replacement parts do that to me ! Paps

T. Cotten
12-30-2006, 07:21 PM
Paps has described a nasty circle that we all fall into occasionally,.... and comparing notes among us is certainly the only way to protect ourselves, and improve our 'lot', whether we are providers, or consumers, or both..

So let us be patient rather than vindictive.

There are no well-defined boundaries between 'manufacturer' and 'distributor' and 'vendor', or often even the 'consumer'.

I'm a micro-'vendor', yet I commission 'manufacturers' (often outside of the vintage motorcycle world) to make 'lots' of parts, and often I am bitten even before they reach me or the 'consumer'. It is often only as a 'consumer' myself do I find the faults,...or at least I hope to, before I get chewed out for them.

The worst aspect of this viscious circle is when a 'lot' (meaning a 'batch') of imperfect parts must be sold off before corrected ones will be made.
Even the best of manufacturers/distributors/vendors follow this pattern: A major manufacturer recently started producing carburetor venturies,...but spec'd them after badly shrunken originals! Even though they were quickly alerted,....their shelves must be emptied before we can expect ones machined to a proper airtight fit.

My point of view is that we should absolutely compare notes on products, but slinging mud at the providers won't help our needs in the long run.


01-01-2007, 11:09 AM
Swall, You may be able to get the threads to work out with some fine lapping compound. A few repeated applications and a little patience will usually prevail.

01-01-2007, 11:51 AM
If it sounded like I was slinging mud, then let that mud cover the targets, neck deep. The solution to inferior replacement parts is a simple one. As in heavy industry, a single part is ran, inspected, tested, and proven. If defects are found in that part, such as machining, casting flaws, locational specs, cosmetics, etc., those defects are addressed before a second single part is ran. This procedure is repeated over and over again until the part manufacturing process is completely corrected. Once the bugs are all worked out in the manufacturing, a full run of parts can be ran. Even with CNC machining, only so many parts can be safely manufactured within specs before machine offsets need recalibrated. This means specific periodic inspections of so many parts during a run. My discription was brief but it does describe what true quality control is. My point is.........inferior parts should never make it to the shelf. The number of inferior parts should be minimal, not complete lots. The few should be scrapped at their origin, not at their originally intended end destination. Referencing heavy industry once again..... I have been privaleged over my time, in manufacturing very large ticket components and other expensive parts and equipment for this industry. Some of these orders took more than a year to fill. Throughout that time period, the customer would send inspectors to our facility and they would spot inspect selected parts and components, long before they left our facility, for any possible defects or deviations from the blueprints supplied. Extremes maybe ? Not when the cash was in the hundreds of millions ! Down scaled, this can be accomplished with bike parts as well. The end result is quality replacement parts. The buck stops at the actual manufacturer but that same buck stops at the suppliers who continually place orders with the same manufacturers who do not implement a sound quality control procedure. It is a given, with these vintage machines, that many of their components need to go through a fitting process. The givens are engine bearings and the like, but, not all the other bolt on parts should need fitting or total reshaping etc.. If the vehicle manufacturers of WWII had supplied the quality of parts that are supplied today, they would have never gotten assembled in time for actual use. How many WLAs were assembled by any one motor pool in any given day, during that time ? Because of inferior, or non existent, quality controls, such as we seem to have today, those very same motor pools could not have assembled even one WLA in a day. And ? What about aircraft, trucks, firearms, ships, jeeps, etc.. ? If the quality controls of yesterday were adequate, though primative to todays so called superiorities, in which to allow for a smooth and rapid assembly of reliable vehicles, many of which still run and operate to this day, then why is it that many of todays replacement parts are not manufactured to at least a small degree of those primitive ancestors ? Answer......simple quality controls ! Grant it....some duplications are difficult due to a lack of originals to clone from, but....the vast majority are available. Bottom line is.....the retailer and consumer should not be the testing grounds, let alone the quality controls. Anyone for a maiden voyage flight on this new fleet of untested or proven jumbo jets ? ;) Paps

03-03-2007, 04:30 PM
Well, I bought one from Jerry Greer and it was still too tight, so I sent it back. Upgraded my lathe tooling (always a good thing) and bought a $60 threading tool from Enco and made a mandrel with the 24 TPI. Put valve grinding compound on the mandrel and ran the nut on and lapped it. After about 7 iterations over two evenings, it went on the cylinder spigot just fine.

03-03-2007, 04:34 PM
Bought one from Jerry Greer and it was also too tight. Sent it back. Decided to upgrade my lathe tooling and bought a $60 threading tool from Enco. Made a 24 TPI mandrel, applied valve grinding compound, ran the nut on and lapped it. After about 10 iterations, it screwed on to the spigot just fine.