Broken Colchester Lathe! 2

[mtrehy]

Hi All,

I'm teaching at a school in the UK, we have an old colchester (not sure of model but can get it if required - it doesn't have the colour coded levers for speed and is a small to medium size).

The lathe has been noisy for a while (bearing noise I think)and now it has given up completely.

The motor seems fine, it is trying to turn the top pulley. The chuck turns fine in neutral. When you try to start the lathe, it sometimes starts (sometimes not, but after a few seconds it grinds to a halt. It then takes some brute force with the chuck removing spanner to turn the chuck/spindle.

My guess is that the bearings are knackered, either in the shaft which has the gear selectors attached and pulley on the back - or perhaps the layshaft bearings.

Does this seem likely? Which bearings are most likely to have failed? Is it a relatively straight forward repair? Are bearings available?

 

[mtrehy]

It's a Colchester Student Roundhead I believe.

 

[funnelguy]

I apologize for my lack of familiarity with your particular lathe. That said, it seems as though you’ve already made 70% of your diagnosis.

Quote, “ The chuck turns fine in neutral. OK, stop looking there…

Quote, “ When you try to start the lathe, it sometimes starts (sometimes not, but after a few seconds it grinds to a halt. It then takes some brute force with the chuck removing spanner to turn the chuck/spindle.

Please, for the love of Mike, stop doing that!!

Disconnect the power to the machine, pull the fuses from the box and lock the switch open. Remove the belt from the motor.

Remove whatever components are necessary to view the gear cluster and selector rod/forks. Check to make certain that a pinned rod or fork hasn’t dropped it’s pin. Attempting to engage 2 gears at the same time is never a good thing.

Again, I am unfamiliar with your lathe. Please make sure the back gear pin isn’t causing problems if the lathe is so equipped.

Perhaps the best course of action would be to find a sympathetic machinist with experience in these matters and press him/her for a favor. Are there any patrons for your school?

 

[metman]

funnelguy,
A star for you. That was one beauteous post. Thought I would laugh myself silly when I read the bold text even though I know you are dead serious. Can't you just picture this guy flying through the air when all of sudden the power train decides to come to life.

Sorry mtrehy. I don't mean to have fun at your expense but you gotta admit it is not a very smart move and yet I have done dumber things.

Jesus is THE life,
Leonard

 

[mtrehy]

I'm not as stupid as you think.... the power was disconnected prior to freeing off.

 

[funnelguy]

mtrehy,

I hope you have had some luck in diagnosing your problem. I wish I could be of more assistance. My 2 hunches were either a gear selection problem on the layshaft or some sort of a partially/intermittantly engaging back gear situation.

I am not old yet, but I've been around manufacturing and machines for about 25 years. Every time I have hurt myself or my equipment has been prefaced by a loss of patience, temper or attention. I have also had many spectacular close calls that make for great stories only because nobody got hurt. What is the old saying about protection for fools and children?

My own shorcomings in this arena are too numerous to list. On several occasions I thought "This is probably not a good idea..." seconds before I required medical attention. In my younger days I would run set-ups I thought were too unsafe for my machinists. Now, how stupid is that?

I only wish for your safety and to not do more damage to the lathe than is necessary. My apologies if I offended you in any way.

 

[finman]

Try contacting Colchester, I've found them extremely helpful in the past with older machines.

http://www.colchester.co.uk/

I think they will be able to supply spare parts and possible a parts book which I've found can double up as manual with the exploded drawings etc etc.
Try "using" the school angle it may ellicit a bit of extra assistance.
If you don't get any help from Colchecter try

http://www.lathes.co.uk/

they can supply manuals for the older machines.

Best of Luck