[modeleng] Re: Where are you all?

Hello everyone

That's MUCH better!     Four immediate replies, full of most useful 
suggestions!     Thanks chaps!

My detailed replies are below.

Cheers!   Hubert


Hi Jeff D

Thanks for your prompt reply.     I never thought of a model train 
controller.    The wirebound rheostats from RS Components were in excess of 
£50!     If my present solution does not work properly, I will certainly 
follow your suggestion


Hi Patrick

I did indeed think about sewing machine controllers, but the foot operation 
is rather clumsy for this particular


Hi Peter

I did consider the possibility of overheating - and I will knock out several 
of the round discs in the steel container to help with ventilation.


Hi Rich

Thanks for your long and informative message.    I know very little about 
these matters!     The use of this drive will be intermittent, and the load 
light.   If the dimmer fails, they are relatively inexpensive.
I will probably use the clasp nut to disengage the drive, rather than depend 
on the possibly dicey switch.    I have replaced the fuse in the plug to a 
3A.

I have cut a five-groove poly-vee pulley to sit on the end of the leadscrew 
and a mating one for the motor.   The little lathe is on an old Myford 
stand, on the top shelf of  which is a three-phase motor controlled by an 
inverter.     Once again, a five-groove polyvee, in this case cut directly 
into the mandrel     Thus both motors will be directly below the lathe, 
making a neat drive.    I have not yet tried the wiper motor, but the main 
motor works fine, although the diameter of the 'pulley' on the mandrel is 
only 20mm.      The drive to the leadscrew will be very slow, and if it 
slips, I will have to try a tooth-belt drive.    I have a very old Hardinge 
lathe and the ability to change mandrel speed and cutting feed, while 
actually cutting metal, is magic.

To gain extra length for the gear train (I want to use Myford changewheels, 
of which I have a plethora - bought for the Hardinge, where they fit 
perfectly, saving the HUGE cost of Hardinge gears!).
I am considering making a tumbler-gear reversing mechanism on the right-hand 
side of the 'wall' supporting the banjo.   This will give me a  couple of 
extra inches of vertical space to accommodate the Myford gears, and will 
obviously give me 'reverse' - but in 'neutral' it will disengage the gear 
train when the wiper-motor is used.

I cut the leadscrew 10tpi Acme (I have at LH tap!).   I used this thread, as 
10tpi = 2.54mm - near enough to 2.5mm, when cutting fine and short threads, 
to make no difference.   This removes the necessity of a large conversion 
gear.

Good luck with the Hobbymat conversion - let's hear your progress!


This is a heavy little beast, carved out of large lumps of cast iron (my 
main product was swarf!).    If any of you wish to see the work-in-progress, 
give me your email address, and I will send you some pics.

Cheers again!   Hubert


----- Original Message ----- 
From: "Jeff D" <jeffdayman@xxxxxxxxxxxx>
To: <modeleng@xxxxxxxxxxxxx>
Sent: Wednesday, September 17, 2008 12:19 PM
Subject: [modeleng] Re: Where are you all?


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