Hints and Comment

1.   USING "FIBRE" NEEDLES.

"Fibre" needles are made from hardened wood and come from two main sources, Bamboo and Thorn wood.

 In the case of Bamboo needles the bamboo wood is split into a triangular cross-section and a slice taken off the end which leaves a point that can be used to play a single side. The needle can then be sharpened by taking another slice off the end if the bamboo. This can be repeated many times until the "needle" is too short to use. The slicing can be done with a sharp craft knife or blade, or one can use the specially produced cutters produced by HMV, Columbia and others. To use these triangular section needles, the sound box must have the appropriately designed triangular hole for the needle, as found on the HMV No.4 and 5 sound-boxes for example.

The Thorn needles are round in section and can be  re-sharpened using a piece of sandpaper or the specially produced sharpeners such as the "IM" models. These can be fitted into most sound-boxes including the earlier ones with a round hole.

In both cases the "Fibre" needles give a very soft tone and do not produce wear on the record. However they must be sharpened after each playing and well used 78s can wear them out quite quickly.

The pictures below show an HMV cutter for bamboo needles, an "IM" sharpener  and a patent sharpener both for thorn needles. cut2 sh5 sh6

 

 

 

 

 

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2. When you are not using your gramophone, always leave it wound up to some degree to keep some tension in the spring. If the machine is allowed to wind down completely (as some people recommend) the spinning turntable can act as a flywheel and the spring can unhook from the rivet on the edge of the spring barrel and may not re-engage when the motor is rewound.

3. Some 78s get dirty with age and can slow down the motor of your gramophone. This is often put down to weakness of the spring, but is often just drag caused by dirt. I find that cleaning the record surface with WD40 usually solves the problem like magic! I know some experts say that you can cause damage to some of the materials used to make certain 78s, but I have never found this to be so. Use very little WD40 and wipe off thoroughly before playing. You will see that the needle becomes clogged with the embedded grime which can easily be wiped off. Another bit of good advice is to  "soft" needles which cause less drag and wear.

4. I was asked to supply instructions for the replacement of a spring in an HMV 101. So I duplicate it here for anyone who needs it:

        

Replacing the mainspring in an HMV101 motor

Make sure the motor is fully run down.

Remove the turntable circlip and lift off the turntable. Give the central spindle a sharp tap with a hammer to release if necessary.

Remove the motor-board with motor attached by undoing the four screws at the corners of the motor-board. The front part of the motor-board will lift out easily.

Remove the three small bolts that hold the casing around the motor and remove it .

Remove the three  bolts holding the base-plate of the motor.

Lift off the plate and check that a small ball-bearing is in place in the brass cup in which the main shaft sits. The main shaft sits on this when the motor runs. Put a drop of grease in the hole to ensure that the ball-bearing stays in place. Check also that the large washer is in place on the top of the mainspring barrel  and around the barrel pivot.

Lift off the intermediate cog wheel, the washer and the spring barrel.

Oil the governor unit well especially the end pivots and felt pad. Check that the brass plate is clean where the felt pad rubs. Check that the brass plate moves up and down easily on its shaft thus allowing the governor weights to move outwards and back.

Pull out the winding cog from the base of the spring barrel.

The  cover plate of the spring barrel is held in place by a circular retaining spring. Find where the two ends  of the spring meet and prise it off. I use a sharp screwdriver. You might have to hammer the screwdriver under the spring to prise it off.

Lift off the cover plate. If necessary by introducing a punch through the far hole and tapping it with a hammer from underneath. The mainspring will be revealed!!

 Put the spring barrel in a vice, grip the centre of the mainspring with pliers and pull it out carefully. I usually cover it with a towel  while doing this to prevent the spring flying out.

Note the direction of wind for the spring. The HMV 101 mainspring is wound clockwise. Release the new spring carefully by cutting the holding wire, wrapped tightly in a towel and let the spring uncoil slowly. If released too quickly the centre coil may open out too much and will not engage with the winding cog arbor later

Still in the vice ( or similar- I use a jig I made up) with the rivet that holds the end of the mainspring at 9 o’clock, bend the end of the new spring with the hole slightly and locate it onto the rivet (not easy!) then wind in carefully using plenty of ordinary car grease. Keep the loose coil together as much as possible. Eventually the spring drops into place inside the barrel.

Before you close up check that the winding shaft fits snugly into the small loop with the kink at the centre of the mainspring. A groove in the winding cog shaft locates with the kink and is held in place as the spring winds up.

Make sure that the spring sits down as far as possible into the can so that the lid fits in leaving the groove into which the retaining spring will sit

Grind off each end of the retaining spring slightly to make the ends meet squarely later. Put the spring back to hold the lid in place. I usually have to tap the end of the retaining spring with a punch to drive it back into position where the two ends meet. This is tricky and can take ages or might work first time.

Re-assemble the motor in reverse order, mainspring. Intermediate cog. Then make sure that the large washer is on top of the mainspring barrel and that the ball-bearing is still in the brass cup in the top plate. Replace the top plate being careful to check that the intermediate cog shaft comes through. The top plate should sit down flat without rocking. Replace nuts and bolt, then the metal cover.

A few interesting sites are found at:

http://forum.talkingmachine.info

http://www.78rpmcommunity.com

http://p.g.elect.pagespro-orange.fr/phono.htm