Author Topic: Weeden No.1 and Similar Throttle Screw Thread (Read 682 times)

Weedensteam · « **on:** April 21, 2019, 12:28:48 pm »

I have been living under the assumption that they were #6-32 same as No.14 etc. but when I went to add a couple for the No. 7 that is listed in the Parts Drawer I discovered they are a larger diameter.

I have tried all the SAE, BA and Metric that I have on hand and nothing fits. It would appear to be about a #7-32 if such a thing existed.

Stoker · « **Reply #1 on:** April 21, 2019, 02:33:23 pm »

While I do not have a Weeden #7 to compare with, I do have a Machinery's Handbook for reference. But without even referencing that I can tell you that a #7 is pretty much never encountered in the Unified Thread system, and so the next larger from a 6-32 would be an 8-32 with a major diameter of about .164". I will point out that anything is possible if Weeden decided, for whatever reason, to use a proprietary thread, which was not at all uncommon back in the day. Otherwise it could just be a 6-32 from a badly worn die, or an undersized 8-32 at the limit of tolerance .... or beyond.

What is the maximum diameter you are getting from the male threads?

Weedensteam · « **Reply #2 on:** April 21, 2019, 08:44:46 pm »

I am getting confused, my wall chart list major diameter as 0.138

The weeden screws measure 0.137 for one and 0.142 for another sample

This is a stock 6-32 brass machine screw that a nut from another source fits on:

Weedensteam · « **Reply #3 on:** April 21, 2019, 08:57:03 pm »

Replying again because I have difficulties when photos involved.

The two Weeden screws would seem to be close to the spec on my chart, yet the brass screw stock I use and Allen screws I checked come out to the to the 0.133 reading.

A stock nut will not fit on the Weeden screws.

Stoker · « **Reply #4 on:** April 21, 2019, 09:16:05 pm »

A stock nut not fitting on the Weeden screws seem strange, as the nominal major diameter for a 6-32 male thread is .138", so that both of the dimensions that you list for the Weeden screws are within nominal tolerance for a 6-32 Unified Coarse Thread. Not surprised that a brass bolt of probably newer manufacture would be even smaller as it makes looser tolerances still work. From your description so far I would suspect the nut is under tolerance or has a burr or may even be a bit cross-threaded.

Are you sure those are threaded 6-32 and not 6-40 Unified Fine Thread?

Weedensteam · « **Reply #5 on:** April 21, 2019, 09:37:15 pm »

Found this chart, it lists 0.138 as max and 0.132 as minimum for major diameter for 6-32:

https://www.engineersedge.com/screw_threads_chart.htm

I have ordered a split adjustable die that I can open up to get the 0.138 diameter and will try that.

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Author Topic: Weeden No.1 and Similar Throttle Screw Thread (Read 682 times)

Weedensteam

Weeden No.1 and Similar Throttle Screw Thread

Stoker

Re: Weeden No.1 and Similar Throttle Screw Thread

Weedensteam

Re: Weeden No.1 and Similar Throttle Screw Thread

Weedensteam

Re: Weeden No.1 and Similar Throttle Screw Thread

Stoker

Re: Weeden No.1 and Similar Throttle Screw Thread

Weedensteam

Re: Weeden No.1 and Similar Throttle Screw Thread