[Jet user]

hi all , thanks in advance for your help. i have a jet jmd-18pf mill and jet 9x20 lathe . both have served me well for 10 or so years my problem is with the start stop switch on the mill . sometimes when you start the machine it shuts back down when you release the start switch . it used to only do it once in a while but recently it has been doing it alot . you have to hit stop and back to start again to get it to stay running . sometimes several times in a row. it is such a pain . i know the obvious thing would be to check the wiring then if wiring is secure buy a new switch or restore switch if possible . but before i tear into it , i wanted to know first if there is any issues with these switches on the jet machines and if any one has had similar problems . and if i need to get a switch which kind would be best and most importantly what would the specs of this switch be so i can search for a switch with granger etc. i dont mind relocating switch or mounting a control housing on the machine. what would you guys do ??? i dont think i want to pay alot for an exact replacement switch from jet if it is a lower quality switch. especially if i can get a higher quality setup for the same dollars . thanks again bill

[Al_The_Man]

Many of these ROC lathes do not use a standard hardwired latch in for the run relay, but when you push the button it physically pushes the relay armature over to engage the latch contact, if you have this type, it is best to replace it with a common stop start circuit and relay.
Either way, it sounds like you have a bad latching contact on the start relay.
You need to look for a small contactor with 2 contact for the motor and one as a retaining (latching) contact.
Al.

[pete from TN]

MSC in Atlanta? They have some parts for the RF31 style mill drill as they carried it. They may have a switch or something that would work. Another option is to get rid of the electronics althogether and buy a three phase motor and vfd and run the machine at infinitely variable speed that way... JMHO but lastly, take the switch off and go to an electronics supply store and ask them to find a suitable replacement... peace

Pete

[Jet user]

thanks guys , i appreciate the info . i took the switch out from the front panel and checked that all the connections were tight . then i tried the switch again and it works perfect now . i think just moving it around freed up the locking mechanism . now it stays right in when you push it every time. if it acts up again i will just install a new switch. but for now i can save a few bucks.

[Al_The_Man]

Is it the armature push in type as I mentioned?
If so, I am not sure if you can buy these in N.A.?
Even so, If it is this type and does eventually fail, I would convert to the standard stop-start 2 P.B. circuit.
Al.