Colchester lathe check up

Hi All, I have just inherited a Colchester student round top, its a big step up from my old Southbend. Is there a Colchester expert in Hertfordshire or nearby who can come and check it over. It hadn't been used for 30 years. Its up and running now but I am having some issues. I will happily pay the going rate for anyone's time, it would be well worth for my peace of mind. Thanks. Simon

I am afraid I am in east Yorkshire, but if you have any questions, just ask! I have just rebuilt mine, and slid it into its new home, post a picture of your lathe up. Do you have a manual, and is it a Mk1 or Mk1.5?

Phil

Hi Phil.

Thanks for responding, that's lovely. Mine is a MK1.5, I have a PDF version of the manual. My primary problems are , How to check the headstock bearing, and how to replace the main operating lever spring as it falls under gravity so has to held in place whilst working. The manual show a spring but I cant work out whether its buried in the head stock or some where behind the reserving switch can on the back. Once found where can I find a spring as spares availability seems hit and miss and in some case very expensive.

Thanks for any help. Simon

Hi simon, that looks like a Mk1 to me. What makes you think you need to check the headstock bearings? I would just change the oils, fix the lever spring and get making things on it - I’m sure you’ll discover any problems as you go!

Hi Simon, You mean the lever with the reversing lever in the centre of it? I assume you do. when lifted up, it turns on the lathe motor, when pushed down, turns the motor off, and when pushed further down, it applies the spindle brake. It is not buried in the headstock, it is all on display at the back of the lathe. The round enclosure contains the reversing switch, and the square one is the on off switch. the lever with the spring on it operates the on/off switch mechanism, and at the other end is a second lever which has a slot with a threaded shaft running through it, with two locknuts on which is the adjustment for the brake. where the two levers contact is a pair of teeth, which is the locking mechanism which holds the control in the up position. I do not have a pic of this, but I will take one tomorrow when I am back at the shop. I think there is another spring there, which actually does the holding up function, but can't remember ( even though I put it all back together only just over a week ago!) on the bearing front, provided the bearings are not totally shot, you can adjust them. place a bar in the chuck with about 18" sticking out, put a dial indicator on to the top of the chuck(if you have one) and then try to lift the bar, can you feel ANY play, if you can, the bearings need adjusting. Colchester headstocks are noisy, and the tool riding up over the work sounds like it is not set on the centre height of the lathe. The point of the tool must be set as near as possible to the centre line of the work. If you put a centre in the tailstock, and move it up to the tool point, you can set it quite accurately by eyeball. That is a very nice looking Mk1 gap bed, the mk1.5 has the later apron control for sliding and surfacing feeds. you can get lots of info from www.lathes.co.uk/colchester Any more questions, just ask, I will be back on tomorrow night with a pic of the other end of this mechanism If you take the end cover off, there is a triangular plate which is held in position by an allen screw into the neadstock, and two allenscrews at the other side of it, which attach it to the cabinet near where the vee belts come through. if you take this off the spring locking mechanism is behind it.

Phil

Edited By Phil Whitley on 28/05/2018 17:44:51

it is not actually behind the switch, it is at the other side of it. Best way in is to remove the two knurled nuts holding the end cover, then the blanking plate, you may be able to do it without moving the lathe, you may even find the spring is there, but has come off! good luck with it. I found on mine that the on/off lever was fouling the reverse mechanism, so that the reverse lever moved when you operated it. I loosened the clanps on the on off lever, and pushed it a bit further on to the splines, which increased the clearance, and cured the problem.

Phil

If the tool is riding up on the work and the cutting edge is not above centre then... I’m not sure what to suggest unless the spindle is in reverse!

Might be worth checking the toolpost/compound for dive flex under cutting, gib wear on the compound is common on these old colchesters! Best of luck, very tidy looking machine!

Hi All,

Thanks for all the interest, The good news( I think) is the issue that I thought was the head bearing was actually the 6 bolts the hold the headstock to the bed were loose. I have checked the head bearings with a long piece of steel and no play was found. Please see picture which shows marked differences from Phils. Mine lathe has a Matrix clutch so doesn't have the brake so I am still no nearer in where any spring to hold the control leave goes. Anybody? Simon

Take your point Simon, it is different, matrix clutch eh! real nice extra to have, is it single plahse or three phase? I will post these pics for reference anyway. I would take off the end cover, and the triangular plate, if you have one, and have a look in that end. It looks like whatever mechanism yours has hides behind it.

Phil

Makes sense, single phase from new machines had the matrix clutch fitted so the motor was started off load, mine is three phase, and luckily, so is my workshop! I will be interested to see what you find.

Phil.

Matrix clutch is an excellent addition, I run my 3phase Chipmaster from a VFD but still use the clutch to stop and start the spindle when working. Using the clutch on a single phase machine will really help prolong the life of the motor caps and start winding switch. The brake is also great for batch work, when I used to run jobs on my Myford I would spend what felt like hours every job just waiting for the spindle to stop!

Can,t help,but I love looking at old machines like that,light years ahead of my cheapy Chianees job.

Should be able to get good results from it.

Good luck.

according to the diagram of the clutch in the manual, there does not appear to be any internal springs. It is a mystery

Phil

Simon, sorry, I'm late to the party !

Have you resolved your lever problem properly yet ?

If not, I've processed the information in my brain and come to a conclusion as to what the problem could be - badly adjusted clutch. So I start with a statement and a question:

You know to start the lathe, you have to pull the lever out then lift it up. With the motor running, if you gently lift the lever WITHOUT pulling it out, which of these best fits what happens:

Spindle doesn't turn

Spindle turns like the lathe running normally

spindle turns slowly because the clutch slips.

The third option is what you're aiming for. If the spindle runs normally, the clutch is adjusted too tight - and because of this, the lever when pulled out and up, isn't moving far enough up to latch.

To adjust the clutch, remove left hand cover (changewheels cover) and look at the top V belt pulley - the clutch is built into that. The adjusting nut is marked in the manual as ZC8 - and from what I remember, this slides along the shaft to disengage a locking dog, once disengaged, it'll rotate relative to the pulley to adjust the clutch. Once adjusted correctly, snap it back along the shaft to lock it again. I think 'top to you' (front of lathe) loosens the clutch adjustment. With motor stopped, turn it a little bit and retry the starting handle for amount of vertical travel. If I'm right with my guess, loosen the adjustment bit by bit, retrying the control lever FIRMLY to the point it moves further and latches.

If that does the trick, GREAT Then make further minor adjustments of the clutch so that the spindle can be 'tickled' round by gently lifting the control lever without pulling it out - then you'll have the same adjustment as mine and it'll work great !

Hope that helps.

Could anyone please mail me a pdf manual for the colchester student mk 1

Appreciated if you can 

Edited By JasonB on 07/09/2021 06:46:46