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Old 3rd Jul 2005, 6:04 pm   #1
PaulR
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Default Brown felt and soft rubber

I am currently restoring an HMV radiogram. The woodworm in the top have eaten their way through the brown felt lining in places and I would like to replace it. Before I rip it all off, does anyone know of a source of suitable felt?

Also, the rubber suspension in the pickup has perished. I have replaced it with a bit cut from an elastic band, but it is somewhat too hard. Has anyone any suggestions as to a better source of suspension rubber?

Thanks

Paul
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Old 3rd Jul 2005, 8:59 pm   #2
peter_scott
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Default Re: Brown felt and soft rubber

I have a similar problem with my HMV 901 and if I may add a related question, how do you cut felt into nice slim parallel sided strips for such uses?

Peter
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Old 3rd Jul 2005, 11:00 pm   #3
Alvin
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Default Re: Brown felt and soft rubber

Quote:
Originally Posted by PaulR
Also, the rubber suspension in the pickup has perished. I have replaced it with a bit cut from an elastic band, but it is somewhat too hard. Has anyone any suggestions as to a better source of suspension rubber?
A mate of mine uses old fashioned bicycle valve rubber for this - it's not so easy to find these days but last time he needed some I eventually struck lucky in a back street cycle repair shop in Leicester and bought their last half metre....I lost count of the number of cycle shops I'd been in before I found it.

The proprietor wasn't unduly surprised when I said it wasn't for use on cycle valves as he sometimes gets anglers buying it and the last lot he'd sold was for 'summat to do with hedgehogs' The mind boggles!!

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Old 4th Jul 2005, 12:47 pm   #4
pmmunro
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Default Re: Brown felt and soft rubber

The brown felt shouldn't be too difficult to find. Try a shop selling fabric for curtain making and upholstry or a general craft shop - it's used to make felt artwork.

For cutting a steel rule and a scalpel or Stanley knife should work quite well if you hold the straight-edge firmly enough - an improvised clamp may help, and save the fingers. If the width is critical, the clamp could be made of key steel which is available in square bars in sizes up to about 15mm and 300mm lengths. Ground flat stock is another option - see for example RS stock numbers 855-620, 855 340, 855-636 or 855-658, all around £5 a length and probably less from a local engineering supplier or rolling bearing supplier such as BSL.

Peter - if you don't know of the right kind of shop in Edinburgh, take a trip across the water to Kirkcaldy, or Sinclair Town to be exact. The "Rejects" shop there has an extensive soft fabrics section upstairs and you'll almost certainly find what you want there with the aid of the helpful assistants. They don't even laugh at inane male questions, or not until after you've left anyway.

For rubber, have you thought of using strips cut from latex surgical gloves or similar? I believe that they are still made of genuine latex.
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Old 4th Jul 2005, 1:23 pm   #5
Mike Phelan
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Default Re: Brown felt and soft rubber

The problem with cutting felt in narrow strips is that it stretches. My tip is to use a pizza cutter - the sort with a little wheel with a sharp edge.

For cutting rubber, always wet the knife - it works much better.
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Old 4th Jul 2005, 3:23 pm   #6
mickjjo
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Default Re: Brown felt and soft rubber

For the pickup lower pivot rubbers I have used bits of silicon rubber sleeving with success, A wider piece of sleeving can be used for the top damping rubber. A lot of trial and error adjustments are usually needed with these old "blunderbuss" pickups, the aim is to get the armature centralised, but without too much stiffness, which greatly increases record wear. .

Regards, Mick.
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Old 4th Jul 2005, 3:44 pm   #7
PaulR
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Default Re: Brown felt and soft rubber

Mick,

How does the pivot come apart? It appears that it should just pull out and all that may be stopping it is the perished state of the rubber. I haven't tried putting on too much pressure as I am frightened of snapping the leads to the coil which are rivetted to the AF lead terminals.


Secondly, where do you get the silicon rubber sleeving? It sounds just what I need.

Thanks

Paul
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Old 4th Jul 2005, 5:54 pm   #8
Nickthedentist
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Default Re: Brown felt and soft rubber

Quote:
Originally Posted by PaulR
Hmm - this is difficult, trying to get obsolete valve rubber to mend an even more obsolete pickup! There must be something that is a bit more easy to obtain. What about something in the medical line? Nick-the-Dentist are you watching this and can you think of anything?
The only rubbery stuff that comes to mind is:

(1) "Rubber Dam", a sheet of thin rubber about 5" square, that's used to isolate a tooth from the rest of the mouth, so that you can do clever things to it without it getting soaked in saliva

(2) "Wedgets" which is the tradename for a rubbery cord, about 2.5mm in diameter and round in c/s, which is designed to be stretched thin, slid between 2 adjacent teeth, and then let recoil to its normal thickness, to hold the above "rubber dam" in place.

Both are relatively expensive, but I could probably steal you a bit of each if you thought they'd be useful

Nick.
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Old 5th Jul 2005, 10:07 am   #9
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Default Re: Brown felt and soft rubber

I dimly remember that you can get wheel cutters specifically for cutting cloth. Try a needlework or haberdashery store.
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Old 5th Jul 2005, 10:26 am   #10
PaulR
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Default Re: Brown felt and soft rubber

it occurs to me that I have a small sharp wheel thing for cutting wallpaper in awkward places. I could try that. I think it may be easier to cut the felt a little large then trim it with the cutter when stuck down.

I need to treat the woodworm first then it can be allowed in the house.

Paul
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Old 7th Jul 2005, 8:19 pm   #11
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Default Re: Brown felt and soft rubber

Joe's silicon rubber sleeving arrived today (thank you Joe) and fitted the pivot perfectly. It comes apart fairly easily and it was only the perished rubber that was holding it together. It also works for the top damper although it does not fit quite as well as the original.

I have tried it on a modern (1970s) amp and the sound quality is quite amazing; much improved from my elastic band set up. There is also much less noise coming from the pickup and record itself. I can now see why these were advertised as being the wonder instrument of the age in the 30s as the improvement from ordinary gramophones must have been huge. Clearly this is the answer to the bicycle valve rubber problem. Is it available fairly easily Joe?

I was so impressed that I was going to do the modification to an older HMV pickup which I put away as the sound from it was disappointing. Unfortunately the top damper is of a different design and consists of a small sheet of rubber with a slot cut into it. I was wondering whether Nick could send a small piece of the rubber dam so I could try that.

Paul
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Old 16th Jul 2005, 7:54 pm   #12
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Default Re: Brown felt and soft rubber

Silicon rubber sleeving makes first class damping 'rubbers' for all the old style magnetic pick ups. Its also great for redamping the old acoustic sound boxes.
It can be purchased with different wall thicknesses. Regards JOHN.

Last edited by Paul Stenning; 18th Jul 2005 at 6:01 pm. Reason: Removed OT stuff
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