Thread ID Please

[8ob]

I would like to fit these small 4 pin plugs to some Nema motors ,I need to open up and tap the gland holes in the plastic caps but am a bit stumped on thread identification. OD of thread is 15.5 or .6" in old money and the thread is 1mm pitch or 24tpi. Cant find any reference in the Zeus book, anyone?



Bob

 

[Seadog]

The closest I can suggest is 5/8" UNS, which is 24tpi - https://www.tracytools.com/5-8-x-24-tpi

 

[awemawson]

Could be BSB 5/8 which is 26 tpi :

https://www.motalia.com/Html/Charts/bsb_chart.html

 

[Hitch]

I was going to suggest 5/8" unef

 

[Seadog]

It's coarser than 1mm so 24tpi sounds about right. Do you not have an imperial thread gauge, Bob?

 

[rtbcomp]

I have some of these connectors. Measuring the thread with an imperial thread gauge gives 25 tpi, measuring with a metric gauge gives a pitch of 1mm. OD 15.7 to 15.8 mm, 0.609" OD about 5/8"

I'd go with a 16mm OD x 1, sticking to metric sizes.

 

[rtbcomp]

https://www.ebay.co.uk/p/16mm-X-1-Metric-HSS-Right-Hand-Tap-M16-X-1-0mm-Pitch/519516547

 

[Rig Pig]

Might be PG?

 

[bricol]

I would have said PG - but the 24tpi would seem to rule that out - closest on diameter is PG9, but 18tpi

 

[brightspark]

is that metal plug size the same thread as the plastic stuffing gland above ??

 

[8ob]

Thanks for the response guys ,there are threads mentioned here I never knew existed. @rtbcomp I have a few of these so measured them and the largest is 15.5mm, I have ordered one of those 16mm taps but I think its going to be way sloppy. @Seadog I have checked against the imperial guages and its sits better at 25tpi than 24 but I eleiminated it because there seems to be nothing around that diameter with that thread pitch. . @brightspark the gland thread is a lot coarser than the 4 pin plug thread, its a tad smaller so I was hoping to over thread it with the correct tap if one exists.

Bob

 

[rtbcomp]

On mine the nut's a sloppy fit on the male threads anyway.

 

[Tom O]

Have a look here.
https://www.gewinde-normen.de/en/index.html

 

[Johnnybravo]

With electrical connectors and gizmos, the industry seems to be a law unto themselves.With it being a casting,it could be they didn't allow for the 1-2% shrinkage of the part. Have just finished making some nuts for some inductive pickups. Would be lost without a cnc lathe as I couldn't find anybody that stocks M8x0.5 taps.

 

[8ob]

Have a look here.
https://www.gewinde-normen.de/en/index.html

Not in there Tom but that link is by far the most comprehensive I have ever come across, I have saved it . I will start to print off pages and laminate them to keep for workshop use

With electrical connectors and gizmos, the industry seems to be a law unto themselves.With it being a casting,it could be they didn't allow for the 1-2% shrinkage of the part. Have just finished making some nuts for some inductive pickups. Would be lost without a cnc lathe as I couldn't find anybody that stocks M8x0.5 taps.

I think you are right Johny, I have ordered the m16 tapered tap so if I am careful I should be able to go just deep enough to get a reasonably tight fit. Failing that the socket will get gagged in jollop and screwed in

Thanks you all for your input

Bob

 

[Anguz]

you could always fill them with sika.... and worry about getting back in there when you need to

 

[rtbcomp]

Have you had any luck with this?

 

[8ob]

Have you had any luck with this?

Ordered the tap RT but its not here yet, will report back when it turns up.

Bob

 

[8ob]

Tap was in the mailbox @rtbcomp . Anyway threaded the plastic no problem and the plug screws in ok. Tried the tap in one of the backnuts and it removes material . Next job is to workout how to connect those wires to the plug and screw them into the new thread without getting them all tangled/twisted up.

Bob

 

[rtbcomp]

When soldering small connectors like this I fill the solder buckets with solder, strip, twist & tin the conductors and then trim the tinned ends to length. Re-melt the solder in the bucket and push the tinned end of the wire in. Hold it rock steady while the solder sets. I find it useful to connect the plug & socket together so the pins don't move if the heat softens the plastic.

Before screwing the connector in the plastic housing, turn it anti-clockwise to twist the wires together, they will untwist as you screw the connector in (clockwise).