Enlarging Castor Recesses

[Roger Jolly]

Hi Tom,
           Nice to see you in Regina last week.
 I use a 3" dia forsner bit, they are availiable from Lee Valley Tools in
Edmonton. You will need a 3/4" drill heavy duty and slow speed to get the
job done.
Take a 3/4" piece of board and drill a hole right thro' it with the bit.
Use 2 nails to tack the home made template over the hole, the board will
act as a guide and stop the drill jumping all over the place.
It is important to measure the distance from the bottom of the mounting
plate to the bottom of the wheels of both the old and new casters, to
ensure that pedal height is correct.
You will need some kind of depth gauge to make any corrections in depth.
Drill out the old screw holes and plug them with maple dowel and epoxy, do
not use them for the new screw holes, you will get better holding strength
with fresh holes into side grain.
The reason for plugging the holes is to make sure there is lots of solid
material supporting the shaft. The pressure in this area can be several
hundred pounds per square inch.
The other important thing to watch is shaft hole diameter, bore out the old
holes and use the maple sleeves, availiable from Pianophile.  Glue them in
for a long lasting tight fit.
Screw the new casters on with 2" # 8 screws. 
You may have to trim some material off the corners of some trap work boards
to obtain clearance of swivel.
Regards Roger



At 07:58 PM 09/12/99 -0800, you wrote:
>Hi, John!
>
>  Thanks for starting this thread;  hopefully we'll both get an answer.
>
>  I have done a number of these caster jobs on older uprights.  I started 
>with just a chisel, and then hit on the rotary file in my drill.  I use 
>these in combination, now.  But, that's as far as I've gotten, too.
>
>  I wondered about something like a hole saw, but it seems a little flimsy 
>for the type of cutting required;  also, I don't know as I can easily get 
>one in the diameter I need for good clearance.  I like the chisel to finish 
>as a bevel is needed rather that a straight sided cut.
>
>  Anyway, hope the answers out there.
>
>                                                       Tom
>
>
>
>>From: John R Fortiner <pianoserv440@juno.com>
>>Reply-To: pianotech@ptg.org
>>To: pianotech@ptg.org
>>Subject: Enlarging Castor Recesses
>>Date: Thu, 9 Dec 1999 13:38:25 -0700
>>
>>What is/are your favorite methods/tool(s) for enlarging the recess that
>>castors fit into on the bottom of pianos such as when fitting double
>>wheel castors so the arm of the castor doesn't get hung up against the
>>existing recess?
>>I've used chisels and rotary files chucked into a drill  for this - bad
>>wording - I never chucked the chisels into a drill :-), but feel there
>>has to be a better way.
>>
>>John Fortiner
>>Billings, MT.
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Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505