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  1. #1
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    Default Vintage MEM Electrics

    Last year I was lucky enough to be offerred a Wadkin PK dimension saw (albeit a somewhat abused, well used, and a little neglected).

    When I bought it the electric isolating switch had been removed leaving half a PDL switchbox...

    Mem1a.jpg

    In order to test it and get it running I bought a front cover for the PDL box and mounted a 3-phase isolating switch on the front.
    Mem1b.jpg

    But the switch looks so out of place that I'd like to replace it with something more in "period" (the saw was manufactured in 1945)

    Mem1c.jpg

    So I've managed to acquire a Memrex 3-phase, cast iron clad, switch.

    Mem2.jpg Mem4.jpg

    The internal contact blocks look almost identical to the internals of the 3-phase, pressed steel clad, switch, on my 1928 bandsaw.

    Mem3.jpg Mem5.jpg

    I was wondering if anybody here is familiar with Mem electrical boxes, and can estimate the era of these two electrical boxes?

    The bandsaw was relocated in 1987, and I believe the orange conduit dates to that period. I believe the pressed steel switch boxes pre-date that move, but are not likely to be the original electrics of 1929. I would guess maybe the 1960s?

    MEM Co Ltd
    Reddings Lane
    Birmingham
    England

    Cheers, Vann.
    Gatherer of rusty planes tools...

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  3. #2
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    Default

    Check out the ads on Graces Guide some of them may be the correct one MEM Co

  4. #3
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    Default

    My bro worked for MEM here in Sydney in the early 80s.
    They had a manufacturing plant at Artarmon and were the import agents for Makita power tools.
    He's not on the net and is 800 k up the coast but I am going up that way for a wedding in early April so will pick his brains.
    When they shut down he scrounged me a lifetime supply of starters and fuse links etc.
    He also rewired my workshop, replacing the fabric covered wiring in steel conduit with modern wiring.
    Even so we installed a main kill switch next to the door and when leaving it all goes off.
    That switch is definitely pre 1960 and quite possibly prewar.
    H.
    Jimcracks for the rich and/or wealthy. (aka GKB '88)

  5. #4
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    Default

    Quote Originally Posted by Pac man View Post
    Check out the ads on Graces Guide some of them may be the correct one MEM Co
    D'oh, I should have checked Grace's Guide. Thanks.

    While none of the adverts there is for the Memrex range of switches, the switch shown in the July 1938 advert, is similar to the cast iron one I have. And the switches growing on trees, in the April 1946 advert, are the exact same style. So that reinforces clear out's opinion that it may be second world war era. That makes it perfect for my 1945 PK saw .

    None of the adverts (the most recent of which is 1964) show a pressed metal box for a switch - which suggests my guess of 1960s, for my bandsaw Mem switch, may be a bit early. Clear out (Henry), I would appreciate it if your bro is able to throw some more light on the subject. I look forward to your return in April (I too have a brother who doesn't use the net).

    Cheers, Vann.
    Gatherer of rusty planes tools...

  6. #5
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    Default Isolating Switches - Pt 1

    This post has been moved here from another thread. It doubles up on some of the info previously posted here (but also sums up those posts)
    Quote Originally Posted by jgforsberg View Post
    post up what you got Vann...
    My 1928 Preston bandsaw came with a MEM isolating switch in a pressed sheetmetal box.

    Mem3.jpg Mem5.jpg

    This design seems to date from the late 1960s or early 1970s. The orange conduit in the pictures was fitted in 1987, and the switch predates the conduit. So I'd estimate the isolating switch was a late 1970s or early 1980s upgrade to the electrics on the saw.

    The internal contact blocks look almost identical to the internals of this MEMREX cast-iron clad, switch (which is destined for my 1945 Wadkin PK - to replace a modern isolating switch).

    Mem2.jpg Mem4.jpg

    The internal contact blocks also look the same as those in this MEMREX switch.

    1695c.jpg 1695a.jpg

    Though I don't have a clue what the other gear in this box does, nor why there appears to have been only one fuse and two thermal cut-outs (for 3 phases).

    1695f.jpg

    The writing on the thermal cut-out says:
    REQ'D FUSE NOT OVER
    30A 600V
    50A 440V
    75A 250V
    4.0A 600V


    And Yes, I'm very aware that the white fluffy stuff is almost certainly asbestos. I've carefully package up the larger bits and vacuumed up any remaining particals.

    1695e.jpg Box cleaned, vacuumed, and washed.

    MEM and MEMREX are brands of Midland Electric Manufacturing Co. Ltd of:
    Reddings Lane
    Birmingham
    England

    This advert, found on Graces Guide (UK) shows the same style of cast-iron box, and dates to 1946. Another advert showing this style dates to 1938.

    1946-MEM.jpg

    It is likely that the switch with thermal cut-outs was installed ~1929.

    Cheers, Vann.[/QUOTE]
    Gatherer of rusty planes tools...

  7. #6
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    Default Isolating Switches - Pt 2

    From the scruffy box, with dirt and surface rust (and an open 'knock-out') the isolating switch has been cleaned, derusted, plugged, and painted.

    1970d.jpg

    The painting isn't that great, close up. Brush marks are very visible. But from a distance it looks much better, and it's now sealed against sawdust ingress, and rust.

    1970b.jpg 1970c.jpg During strip down, with the ceramic covers (arc chutes?) removed.

    1970e.jpg The 'knife switches' are plated, and are in good condition. They were merely cleaned with Jif.

    1970a.jpg Reassembled, showing broken ceramic cover.

    As seen above, one of the ceramic covers was broken. I was going to use a cover from the "thermal cutout" switch, but they're not interchangable . There have been minor design changes over the years.

    Cheers, Vann.
    Gatherer of rusty planes tools...

  8. #7
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    Default Disassembling the MEMREX Switch

    Quote Originally Posted by Vann View Post
    Last year I was lucky enough to be offerred a Wadkin PK dimension saw (albeit a somewhat abused, well used, and a little neglected).

    When I bought it the electric isolating switch had been removed leaving half a PDL switchbox...

    Mem1a.jpg

    In order to test it and get it running I bought a front cover for the PDL box and mounted a 3-phase isolating switch on the front.
    Mem1b.jpg

    But the switch looks so out of place that I'd like to replace it with something more in "period" (the saw was manufactured in 1945)

    Mem1c.jpg

    So I've managed to acquire a Memrex 3-phase, cast iron clad, switch.

    Mem2.jpg Mem4.jpg
    Now that my Preston bandsaw is usable (not completed, but usable) it's time to get my Wadkin PK saw reassembled. Starting with a more respectable isolating switch - the MEM switch mentioned above.

    First I removed the lid by tapping out the hinge-pin.

    aMEMlid.jpg The box has been repainted light grey, but inside the original darker grey (not black) is visible.

    Then I removed the ceramic contact blocks - revealing what is most likely asbestos. This I carefully scrapped off and double bagged, then I scrubbed the whole box and all the parts in soapy water to get rid of any traces.

    aMEMbase1.jpg

    The bottom ceramic piece (contact block) screws into the cast iron base. the top ceramic piece (arc chute) screws into the head of the lower screw.

    aMEMceram2.jpg aMEMceram1.jpg

    Then I removed the switch bar. This locates on a spring cam mechanism at one end, and is removed by removing the pivot screw at the other end.

    aMEMbar1.jpg aMEMbar2.jpg

    Cheers, Vann.
    Attached Images Attached Images
    Gatherer of rusty planes tools...

  9. #8
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    Default The Switch Bar

    Upon inspection, some of the switch bar knife contacts were badly out of shape.

    aMEMbar4.jpg

    First I marked the location of each knife contact with a marker pen.

    aMEMbar3.jpg

    Then I loosened each knife contact and slid them off the bar.

    aMEMbar7.jpg

    Each bent knife contact was straightened.

    aMEMbar5.jpg aMEMbar6.jpg

    Then lightly abraded and refitted to the bar.

    aMEMbar8.jpg

    I won't refit it to the cast box until I've repainted the box.

    Cheers, Vann.
    Gatherer of rusty planes tools...

  10. #9
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    Default

    In case anybody is wondering, and stumble across this thread:
    Quote Originally Posted by Vann View Post
    ...I was wondering if anybody here is familiar with Mem electrical boxes, and can estimate the era of these two electrical boxes?...
    I recently purchased 3 MEM cattledogs from the UK, for not too much money (£10).

    s-l1600.jpg


    The newest dates to 1962, while the others are 1955 and 1937.

    The cast iron clad switch is in the 1937 catalogue* but not the 1955 version.

    Mem4.jpg

    * this catalogue only shows the internals of each switch. At some point MEM changed from smooth fronts on their isolating switches to the more decorative version.

    1695c.jpg Mem2.jpg Smooth front (left) & decorative front (right).

    The smooth front isolating switch was originally black ("jet black" according to the catalogue) and I believe it dates to ~1929 (it came off a machine installed in 1929). The decorative front isolator was originally grey, and I guestimate it's post WW2 (it is said there was so much "battleship grey" paint left over at the end of WW2 that nearly everything got painted that colour - probably just urban legend ).

    It would seem that MEM cast iron clad switches went from plain black front, to decorative black front, to decorative grey front - before being replaced by a more modern looking cast box in the 1955 catalogue (possibly die-cast aluminium) and then the pressed steel clad switches - with almost identical internals.

    The pressed steel box isolator isnít in the 1955 catalogue, but appears in the 1962 version


    1970a.jpg

    Quote Originally Posted by Vann View Post
    D'oh, I should have checked Grace's Guide...

    ...None of the adverts (the most recent of which is 1964) show a pressed metal box for a switch - which suggests my guess of 1960s, for my bandsaw Mem switch, may be a bit early. Clear out (Henry)...
    I had already identified that these pressed steel boxes were around in 1963, as I found this photo taken that year.

    Pattern Shop Safety Record - V4.jpg

    And if you look in the bottom right-hand corner (under the bandsaw table) you can see a Crabtree contactor and the MEM pressed steel isolator - both looking in new condition in 1963, on this 1929 Preston bandsaw. That is the very same MEM isolator as shown in the previous photo.

    aSwPres.jpg aPresElect2.jpg The same two electrical items before and during refurb - since I purchased the saw three years ago.

    Pretty cool I reckon, having a photo of my own bandsaw, taken 56 years ago .

    Cheers, Vann.
    Attached Images Attached Images
    Last edited by Vann; 17th May 2019 at 11:49 AM. Reason: More info added.
    Gatherer of rusty planes tools...

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