Page 1 of 1

Machined parts for 750s

PostPosted: Sat Jan 03, 2009 6:31 pm
by Martin Kemp
I have just bought Barbara a new lathe for Christmas - well it was new in 1967.
So now I can make lots of turned parts for 750s.

It is a Colchester Bantam with an 11" swing so it can handle anything that we need for our cars.
I have yet to find out how accurate it is, but it should be quite adequate for most 750 parts.

Things I can make on it include:

Gearbox shaft spigots
Rear disc brake conversions
Aluminium Viva type hubs - possibly stub axles and uprights as well.
Wishbone and radius arm end fittings - including UNF left hand threaded ones for adjustable radius arms.
Balance adjusters for brake pedals

Any further suggestions for useful stuff.

Before I start I need a single phase to 3 phase converter - the Bantam has a 2 speed motor - does anyone have any expert advice to offer,

Martin

Re: Machined parts for 750s

PostPosted: Sun Jan 04, 2009 12:05 am
by tonybraz
Hi Martin, I run my lathe and mill on a inverter and change plugs witch ever I need to use. Both machines run 2hp motors 2800rpm in Star configeration and speed control is by a small potentiometer. I would dump the motor and look for a dual voltage on flea-bay, I paid £20 delivered for a 1hp on my cnc mill.Wiring is easy let know if you need anymore info.

Tony

Re: Machined parts for 750s

PostPosted: Sun Jan 04, 2009 12:29 pm
by Worzel
Martin Kemp wrote:IBefore I start I need a single phase to 3 phase converter - the Bantam has a 2 speed motor - does anyone have any expert advice to offer,

Martin


May I respectfully suggest that you just change the motor for single phase. They are so cheap now that a 3/1ph. converter is not really economic. You just need to bear in mind that the cheap modern single phase motors have poor/non existent starting torque so the machine you are driving needs to have a clutch which I seem to recall the Bantam does have.

I have found that new motors are even far cheaper than recon British motors. Screwfix are a good place to start and e bay of course.

Hope this helps

Re: Machined parts for 750s

PostPosted: Thu Jul 09, 2009 9:17 am
by RobSmith
Use an inverter!
I have just gone through the using a single phase motor on my Colchester Student lathe.
The single phase motor is rough and noisy compared to the 3 phase motor.
Single phase drops through 0V every cycle so the motor runs noisier than three phase which is driven in a more continuous manner.
Startup is an issue so needed a capacitor start / capacitor run motor.
I also fitted a centrifugal clutch to soften the startup.
I am running this through a 20A 'C' type (delayed break) circuit breaker which provides enough oomph for the startup.
The modern motor I have also got on the lathe cannot cope with numerous starts. Whilst turning there are a lot of stop/starts for measuring and tool changing etc so my crap modern motor is getting rather cooked after about an hour of use.

I am soon going to revert back to the old Crompton 3 phase motor and spend a good dolop of cash on a good meaty inverter with reverse and soft start features.

Rob

Re: Machined parts for 750s

PostPosted: Fri Jul 10, 2009 7:12 pm
by Martin Kemp
I am indeed using an inverter which I can also use for my newly aquired 1954 Herbert OV milling machine.
The variable speed control is very useful for all sorts of tasks such as grinding in valves.


Martin