<html><head></head><body><div style="color:#000; background-color:#fff; font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:13px"><div id="yui_3_16_0_ym19_1_1464657142826_3660" dir="ltr">Switchcraft had several methods of making the 1/4" phone plug while I was working there. They mostly used the same tip part. This had the tip with a long, thin shaft that would run up inside the sleeve body and be swaged over to hold the parts together. The simplest used a phenolic washer to separate the tip and sleeve behind the tip and another between the two solder/screw terminals on the inside of the connector. With use, the swage would loosen and the connector would become intermittent. This was easy to tell because you could rotate the tip with your fingers. There was a paper tube that covered the tip shaft when it was slid inside the sleeve body. Phenolic isn't great for holding off the 1500 volts RMS that the IM-13 could withstand. Phenolic is porous and is easily contaminated with moisture and oil. For a while, Switchcraft used a black washer in place of the phenolic and then went to black injection molding. Injection molding was used for the long spacer as well. I believe the greater spacing was due to the use of the stereo sleeve without the ring parts installed. Switchcraft already had tooling for making these two sleeves, the mono and the stereo. At the time, all body parts were nickel plated brass. The electrical terminals were tin plated to ease soldering.</div><div id="yui_3_16_0_ym19_1_1464657142826_4469" dir="ltr">At the time Switchcraft was making mil spec 1/4" plugs using the injection molding process in either red or black for use on telephone switchboards and audio patchbays. You could buy them with either red or black handles or you could specify a particular color if you were buy in large quantities.</div><div dir="ltr">Al</div><div dir="ltr">WB9UVJ<br></div><div id="yui_3_16_0_ym19_1_1464657142826_3075"><span></span></div> <div class="qtdSeparateBR"><br><br></div><div style="display: block;" class="yahoo_quoted"> <div style="font-family: Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 13px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"><font face="Arial" size="2"> On Monday, May 30, 2016 11:00 AM, "heath-request@puck.nether.net" <heath-request@puck.nether.net> wrote:<br></font></div> <br><br> <div class="y_msg_container">Send Heath mailing list submissions to<br> <a ymailto="mailto:heath@puck.nether.net" href="mailto:heath@puck.nether.net">heath@puck.nether.net</a><br><br>To subscribe or unsubscribe via the World Wide Web, visit<br> <a href="https://puck.nether.net/mailman/listinfo/heath" target="_blank">https://puck.nether.net/mailman/listinfo/heath</a><br>or, via email, send a message with subject or body 'help' to<br> <a ymailto="mailto:heath-request@puck.nether.net" href="mailto:heath-request@puck.nether.net">heath-request@puck.nether.net</a><br><br>You can reach the person managing the list at<br> <a ymailto="mailto:heath-owner@puck.nether.net" href="mailto:heath-owner@puck.nether.net">heath-owner@puck.nether.net</a><br><br>When replying, please edit your Subject line so it is more specific<br>than "Re: Contents of Heath digest..."<br><br><br>Today's Topics:<br><br> 1. Phone plug for VTVMs and VOMs (<a ymailto="mailto:rgroh@swbell.net" href="mailto:rgroh@swbell.net">rgroh@swbell.net</a>)<br><br><br>----------------------------------------------------------------------<br><br>Message: 1<br>Date: Sun, 29 May 2016 17:09:41 +0000 (UTC)<br>From: <<a ymailto="mailto:rgroh@swbell.net" href="mailto:rgroh@swbell.net">rgroh@swbell.net</a>><br>To: Boatanchors3 List <<a ymailto="mailto:boatanchors@puck.nether.net" href="mailto:boatanchors@puck.nether.net">boatanchors@puck.nether.net</a>>, Heathkit<br> Listserve <<a ymailto="mailto:heath@puck.nether.net" href="mailto:heath@puck.nether.net">heath@puck.nether.net</a>><br>Subject: [Heath] Phone plug for VTVMs and VOMs<br>Message-ID:<br> <<a ymailto="mailto:1074166575.1268186.1464541781335.JavaMail.yahoo@mail.yahoo.com" href="mailto:1074166575.1268186.1464541781335.JavaMail.yahoo@mail.yahoo.com">1074166575.1268186.1464541781335.JavaMail.yahoo@mail.yahoo.com</a>><br>Content-Type: text/plain; charset="utf-8"<br><br>Lost the email but a month or so ago, someone was looking for a phone plug which had a somewhat wider band of insulation between the tip and body. This type of plug was used on probe's (where they plugged into a meter) to give a bit higher breakdown voltage. <br><br>I do have some of those so email me if you need one.<br>As an additional comment, I visually examined about 10 of those phone plugs - some with the narrow insulation band and some with the wider insulation band.? ALL of them seem to have (again just a visual inspection) identical lengths - from the base of the plug body to the tip of the plug.? The wider insulation does not make the probe longer.? <br><br>Bottom line: you don't need the special wider insulation version - the regular will work nicely .... unless of course it breaks over on high voltage. <br><br>73Bob, WA2CKY<br><br>-------------- next part --------------<br>An HTML attachment was scrubbed...<br>URL: <<a href="https://puck.nether.net/pipermail/heath/attachments/20160529/6be9a97a/attachment-0001.html" target="_blank">https://puck.nether.net/pipermail/heath/attachments/20160529/6be9a97a/attachment-0001.html</a>><br><br>------------------------------<br><br>Subject: Digest Footer<br><br>_______________________________________________<br>Heath mailing list<br><a ymailto="mailto:Heath@puck.nether.net" href="mailto:Heath@puck.nether.net">Heath@puck.nether.net</a><br><a href="https://puck.nether.net/mailman/listinfo/heath" target="_blank">https://puck.nether.net/mailman/listinfo/heath</a><br><br><br>------------------------------<br><br>End of Heath Digest, Vol 65, Issue 13<br>*************************************<br><br><br></div> </div> </div> </div></div></body></html>