Bridgeport J Head power feed

[Roger Beere 1Participant @rogerbeere1]

Hi all.

The x axis power feed on my Bridgeport series 1 J head mill has packed up allowing only rapid feeds assuming this to be the potentiometer. The one fitted is a Colvern 1106/9S 50KK 8C03 which seems to no longer exist. I have a feeling that this is not the original component anyway due to the way it has been connected. Has anyone had to replace this component if so with what and where was it purchased. Any help would be appreciated. Roger.

[Roger Beere 1Participant @rogerbeere1]

[Clive FosterParticipant @clivefoster55965]

50 K ohm linear potentiometer for the Erskine feed control board. Get a decent quality one. Cheap carbon film £1 jobbies won't last. RS or Farnell do professional types for £5 or £6. Probably E-Bay and other sources too. Mine wears a mil-spec wirewound & cermet compound one which is way overkill (one of the perks of working for an MoD research establishment at that time).

Clive

[Roger Beere 1Participant @rogerbeere1]

Hi Clive. Do you have a reference number/ product number by any chance. Electrics are not my forte. Roger

[Clive FosterParticipant @clivefoster55965]

Roger

Just had a quick look through CPC, Farnell and RS Components sites and found a few likely candidates. List prices are of the order of £6.00 for most. Prolly £10 ish after VAT and postage. I tend to favour 1 watt rating "professional" level components for this sort of thing rather than the common hobby/ mature level £1 or less carbon film devices found all over E-Bay and from folk like Maplin. Power rating is certainly overkill but reliability and durability will be good.

CPC, **LINK**, part numbers RE 04556, RE 04600 and RE 04540 should all be fine although last one is lower power rating.

Farnell, **LINK**, part numbers 9609369 and 9609563 should be fine, again last one is lower power rating.

RS, **LINK**. , part numbers 851-7385, 522-5080, 743-5719, 410-227 should all work.

Sanity check. Looking for 1/4" (6.35 usually) diameter shaft, panel mount, 50 K ohm linear rating cermet or conductive plastic element. Probably best to verify that the threaded mounting bush is good fit in the hole provided. They do vary and I've not checked. A sloppy pot is a right PIA to use if it starts slipping.

Hope this helps.

Clive.

[Roger Beere 1Participant @rogerbeere1]

Thanks very much for your time Clive. Will get back to you with results. Regards. Roger

[Roger Beere 1Participant @rogerbeere1]

Hi all. Got a pot from the above link. Working perfectly. The original had 3/4 turn from zero to maximum, the new one has 14 turns. Finer tuning.

Roger

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