Garrard Super Motor. Reinventing the wheel............

Discussions on Talking Machines of British or European Manufacture
gramophoneshane
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Re: Garrard Super Motor. Reinventing the wheel............

Post by gramophoneshane »

I'm just curious what original colour/s velvet others have on their turntables?

Mine has a teal blue which I imagine has faded from a stronger medium blue.
Unfortunately I can't photograph it because it's still packed away.

Did they all come in blue or was there a choice of colours available?
I guess a colour change may have happened when the modified 2nd version was made?

It seems a shame to have such a good motor packed away doing nothing, so I'm seriously thinking about building something so I can play my 20" Pathés.
Does anyone know whether these motors will reach 120rpm, or approximately what the high end speed of these motors might be?

I was thinking I could possibly move the governor along its axis to get a bit more grunt out of it, but that may risk the governor balls striking something it shouldn't.
Again that's something I'll have to look at once I pull it out.

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emgcr
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Re: Garrard Super Motor. Reinventing the wheel............

Post by emgcr »

Hello Shane,

Interesting questions and I am not sure about the original colour of the velvets but I have seen blue and brown on Garrard turntables. The excellence in design of these turntables is the ease in which the velvet can be replaced---cut oversize without the need for high precision and then tucked into the external rail forming a perfect circle---much easier than HMV !

Regarding the maximum motor speed : In standard form, I do not think you would easily be able to achieve 120 rpm. I have just fired my laser tacho' at the edge of a record with reflective white spot added and found that the maximum speed available is 103 rpm with the plunger speed control pin fully depressed (later all-internal oil-feed model). There is very little space available to move the governor assembly along its axis thus realistically, in order to increase speed, stronger leaf-springs would be necessary so that the weights would reach a similar centifugal diameter at higher revolutions. A case of trial and error I feel.

The other question is whether the Garrard double main drive coil-springs (2 x 1" width) would produce enough torque to drive the heavy 20 inch discs ? The single Pathé Concert mainspring has a width of 45mm (1.77") and is pretty robust in section. My guess is that they might just work but records could require hand-spinning to start where the load is greatest. The Pathé design includes a clever initial mechanical accelerator. An interesting experiment. Let us know how you get on !

anchorman
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Re: Garrard Super Motor. Reinventing the wheel............

Post by anchorman »

Graham,

do you still have any of the rubber washers you had made up? The washer on my pump seems good, but it wouldn't hurt to have a spare!

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emgcr
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Re: Garrard Super Motor. Reinventing the wheel............

Post by emgcr »

Jon, I do but only very limited quantity. Try yours first please---if in trouble I can help.

anchorman
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Re: Garrard Super Motor. Reinventing the wheel............

Post by anchorman »

My external piping, and how I removed it. There is a fair bit of crusty stuff all over the bottom of the pump, but it cleans up easily enough. I’ll either use some Teflon pipe dope or a drop of blue loctite to help seal the threads upon reassembly.

The leather washer seems supple and undamaged, most likely whatever oil was used did not acidify terribly as it oxidized with age.
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anchorman
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Re: Garrard Super Motor. Reinventing the wheel............

Post by anchorman »

to anyone wondering whether they have enough oil in the motor, if you remove the chromed top plate, it reveals the spot where the oil goes when it is pumped up from the sump. winding the crank will cause oil to squirt out if all is functioning properly. if oil does not come out, you either have a damaged pump, clogged pipe, or not enough oil.

anchorman
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Re: Garrard Super Motor. Reinventing the wheel............

Post by anchorman »

Graham,

I’ve got everything cleaned up nicely, and found two more things that probably need attention. These are the washers either side of the mainspring barrel, between the barrel and the two gears on the bottom there looks to be a square rubber washer, but it is hard as a rock. If you recommend leaving it, I will likely do so, but it should be easy enough to source a new buna-n oil resistant washer of the appropriate size.

The top side gasket has four layers of felt, two between the gear and a little metal cup, and two more in the cup.

Do you (or anyone else have opinions about how hard the rubber washer should be, and also about the density of the felt used on the upper washers? I can source good quality wool felt in various densities/hardnesses from a local industrial supply. Cutting it to size is a trivial job using a laser cutter, so I can happily make some to share with others when I make mine. I’m wondering if all of the layers of felt are actually supposed to be in the cup/ring. I am definitely not the first person to have ever opened this motor, so I’m not sure how they were intended to be installed originally - I can only go off of how they were placed when I took this bit of the spring barrel apart.
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emgcr
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Re: Garrard Super Motor. Reinventing the wheel............

Post by emgcr »

Jon, As you say, one tends to find many different situations when opening one of these motors due to varying opinions as to how things should be done ! The bottom spring barrel washer is usually made from hard (fibre) material due to it needing to be used in a thrust capacity. There is sometimes also a slip ring (or two) incorporated. The top one(s) are there mainly to try to stop ingress of oil which can leach out spring grease if present in too great a quantity.

anchorman
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Re: Garrard Super Motor. Reinventing the wheel............

Post by anchorman »

emgcr wrote: Fri Oct 16, 2015 9:41 am Here is a schematic drawing of the Super Motor.

Click on image to enlarge.
Any chance we could get you to post this schematic again? I'm hoping it might give a little bit of insight into the order of installation, and number of felt washers that are required on top of the spring barrel. And it would, of course, just be interesting to see, regardless.

anchorman
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Re: Garrard Super Motor. Reinventing the wheel............

Post by anchorman »

I'm also looking for information on the threads used throughout. HMV in the UK apparently used the standard threads from the USA on many if not all motors and parts. Are the fasteners on these motors british standard or something else?

The winding crank threads are also eluding me at the moment. My motor came without a crank, so all I've got is the internal threads to go by. They're close to ⅜" threads, but the pitch is not UNC ⅜-16. The minor diameter of the female threads is about .335", which is compatible with any number of ⅜" male threads. Did the British make their winding handles with whit worth standard 55° thread form? Or are they the American standard 60°?

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