Colchester Student worn lathe bed

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Colchester Student worn lathe bed

This topic has 11 replies, 10 voices, and was last updated 10 February 2018 at 15:06 by thaiguzzi.

Viewing 12 posts - 1 through 12 (of 12 total)

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1 February 2017 at 11:40 #32892
Luke Holland
Participant
@lukeholland34397
Should I have my Colchester Student bed reground
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1 February 2017 at 11:40 #281714
Luke Holland
Participant
@lukeholland34397
Hi all,

I am hoping one of you fine fellows may be able to assist me with my Colchester Student and what appears to be a worn lathe bed. Let me start by saying that I am not overly familiar with what is considered "worn" for a lathe bed but I have a feeling this may be considered in a quite bad state! I have attached some pictures to demonstrate the issue but basically I acquired this lathe (Colchester Student MK1) about 12 months ago and it looks like it was used heavily in a factory setting (the bed feels about 0.5mm worn at the worst point). I have had to fix a few aspects of it (worn worm drive housing and saddle locking bolt) and I would like to restore it to as good as new (well that may be pushing it a bit but you get the drift). Anyhow, the two remaining problems are what I feel is a worn bed (ways) and a loud headstock (in any gear). I have tried to test the accuracy of the lathe by putting a steel bar (approximately 2" diameter) in the chuck and having it extruded by 6". I have taken a light cut along the bar and found that for every inch of longitudinal travel the diameter of the workpiece reduces by 1 thou (6" = 6 thou out). I have had a quote from a company to regrind the ways and to turcite the saddle etc. It sounds like a comprehensive process and I have been assured it would bring the lathe back to its original levels of accuracy. However this is going to cost approximately £1200.

I was hoping for some advice really as I will only be using the lathe as a hobbyist but I do want to (possibly) get a small business up and running. Basically is it worth doing, I only paid £1000 for the lathe to start with but I feel that even if I bought another lathe for the £1200 it won't have as good a bed as this would after spending the money to have it regound.

Thanks in advance

Luke
1 February 2017 at 11:53 #281719
JasonB
Moderator
@jasonb
Before making any decision I would get a more accurate measure of what wear there is, "Feel" is probably not the best way to do it.

A known straight edge and feeler gauges would be one way or possibly a DTI run along the flat part of the bed that the saddle does not contact and compare readings.

I see from the photo that the head has been off, if it was not put back true that could also be giving you a tapered workpiece.

J
1 February 2017 at 12:00 #281722
Ian Parkin
Participant
@ianparkin39383
I wouldnt spend that sort of money on a mk1

I had a mk1 for 20 years it was worn out when i got it and it didnt get better with time

However I sold it easily to someone who just wanted a single phase lathe to do simple things and he was delighted at £500

I bought a very unused Mk1.5 for a £1000 ( with lots of tooling which on selling i got my £1000 back ) spent a lot on it to get it perfect and fitted dro's

I was at an auction last week and they had student 1800's and they only went for £400 ish

whilst these machines looked rough ( paintwork etc) the beds were in sound condition.

Before spending on your worn out example i'd look for a unworn one first
1 February 2017 at 20:25 #281812
Phil Whitley
Participant
@philwhitley94135
You should also check out the hyeadstock noise and see what the problem there is, new bearings are horrifically expensive, even when available. Given that the lathe is in bits, you need to get a list together of everything it needs, then decide if it is worth it. I have one of these lathes, and it is a damn good machine, with very little bed wear, and although I have not done any testing or alignment on it, it makes the parts I need as it is, and TBH is far more accurate than I am! Accuracy is the operator more than the machine, It entirely depends on whether you want to restore machines or make parts. As has been said above, you will have to realign the headstock when you refit it, but this is not really a difficult task. There are plenty of used parts availableand new parts like cross slide nuts etc. Of course once you have one lathe up and running, you can make parts!

Phil
2 February 2017 at 07:43 #281878
Hopper
Participant
@hopper
How much wear is worn out? It varies. But Myford literature specifies that .005" of bed wear is enough to need the bed regrinding. So your half a millimetre is probably cause for concern. However, you do need to measure exactly how much wear is there, either with a straight edge and feelers, or a depth micrometer if there is an unworn section next to it, or by mounting a dial indictor on a long extension from the saddle, then running the saddle back and forth on the relatively unworn tailstock end of the bed while tracking the dial indicator on the worn section at the headstock end.

Noisy headstock is indicative of perhaps headstock bearings worn out, something that will also cause misalignment and tapered turning.

If you put your lathe back together and sell it for the 1000 pounds you paid for it, then put together the 1200 pounds bed regrind price and the cost of possible headstock bearings which can be as much again I hear, you are on the way to having enough money to buy a better lathe. Plus you have to figure on a lathe that has worn out its bed and bearings, there will be other worn out things that need money spending on too. EG, tail stock base and barrel, tops slide ways, cross slide ways, leadscrew (both main and the cross slide) , half nuts, drive gears etc etc.

+1 on really sit down and list out all the actual expenses and inspect every tiny part of the lathe to determine just what those expenses will be. Then compare with the cost of selling the lathe for what you can get and buying something ready to use. Beware of putting serious money into old machinery that ends up needing more, and more and more every time you look at the next stage. It's a slippery slope!

Edited By Hopper on 02/02/2017 07:45:12

Edited By Hopper on 02/02/2017 07:45:54
2 February 2017 at 09:06 #281887
Luke Holland
Participant
@lukeholland34397
Hi all,

Thanks for the replies. Well I'll have to have a look at exactly how worn out the bed is, I've got some feeler gauges somewhere which I'll try and dig out later. Its a pain really, as soon as I got the lathe I noticed the topslide nut was knackered and the topslide would not budge! I spent ages trying to disassemble it just to replace the nut (which I ended up making on my mini lathe). I am just thinking of selling it but I've stripped the whole lathe down now, moved it up into the workshop and have started to strip the paint off the base. I was hoping that as long as the bearings were ok then the bed would be the last expensive job, the only good thing so far is that the chap who I bought it off replaced the 3 phase motor with a new single phase one prior to me buying it, so that's one less expense.

Whilst we're on the headstock bearings, how can I test if these are worn? I've tried putting a sturdy bar into the chuck and moving this whilst a DTO is on the end and no movement seems to be present but is there a better way to test if these are knackered?

Thanks again

Luke
2 February 2017 at 09:32 #281891
Nigel McBurney 1
Participant
@nigelmcburney1
I have owned 4 colchesters in the past 25 tears,if its noisy in the gears and has a worn bed the tailstock will also be worn and below centre, so I would quickly part with it,dealers don't like noisy headstocks as one dealer told me they are trouble,worn tailstocks are difficult to put right, square head machines have adjustment to correct alignment ,it may have had a jam up or the chuck jaws colliding with the work though it does take a big bump to put it out of alignment,Colchesters really pull down the socket screws tight . Avoid variable speed machines. If you want to earn money in future go for a Master 2500 they are the best of the 6 1/2 inch Colchesters,pay some decent money for a good one,hear it running,check the spindle nose for burrs and bruising,check tailstock centre height and the morse taper for damage,make sure clutches do grip and feed lever stays in engagement,it is better to spend good money on the machine and not expect to do any further work on it as spare prices are horrendous.
6 February 2018 at 09:14 #339989
Oliver Dudley
Participant
@oliverdudley76320
I have a Mk1 Master that I bought about 12 years ago for 200 quid. I put a new motor and inverter on it and used it for bits and pieces. It was always very noisy (a couple of the gears in the headstock are very badly worn) and I struggled to make accurate parts over any real length. About a year ago I had a proper look at it and found the bedways for the saddle and its accompanying groove were badly worn, the saddle was almost 1mm lower on the left hand side!

I recut the 45 degree vee on the milling machine to make it the same depth all the way along, and DIY reground the saddle vee by making a sled that ran on the tailstock ways and a jig to hold a grinder at the right angle. I kept going until the vee was a consistent height all the way along. Before I started it was cutting about a 0.15mm taper over 150mm, now it cuts about a 0.02 taper over the same 150mm near the chuck, which is good enough for me.

I solved the noisy gearbox by making a new belt drive to bypass it entirely. I made a couple of poly-v pulleys on the lathe as it was, and remounted the motor higher up. They are both stepped pullleys so I've got a 1.5:1 and a 4:1 ratio, in practice it will put a 25mm drill through steel on the 1.5:1 ratio on a slow speed from the inverter, so I have little use for the other ratio.

It's a 60 year old machine that most people would scrap, but with a little tinkering it's good enough for what I want to do now!

Pics below:
8 February 2018 at 20:50 #340492
Jon
Participant
@jon
I can see it Luke thats quite bad, will need nothing short of a full proper regrind.
Scrapped a Harrison 140 8 yrs ago in about that condition, that left pronounced lips on the V's from the saddle.

Choice is cut your losses and flog for parts or strip down fully, setup etc for around £900 + delivery to a regrinders. When done be worth about that but will be in another league on asian imports its British iron.
Personally i would get rid of, its had a lot of use, lead screws aint cheap so are other bits. Add that to above measured by the £100.
If it were the bigger flat top Student or bigger then yes do it up, they dont make em like they used to.
8 February 2018 at 22:47 #340513
Neil Wyatt
Moderator
@neilwyatt
Posted by Oliver Dudley on 06/02/2018 09:14:34:

I have a Mk1 Master that I bought about 12 years ago for 200 quid. I put a new motor and inverter on it and used it for bits and pieces. It was always very noisy (a couple of the gears in the headstock are very badly worn) and I struggled to make accurate parts over any real length. About a year ago I had a proper look at it and found the bedways for the saddle and its accompanying groove were badly worn, the saddle was almost 1mm lower on the left hand side!

I recut the 45 degree vee on the milling machine to make it the same depth all the way along, and DIY reground the saddle vee by making a sled that ran on the tailstock ways and a jig to hold a grinder at the right angle. I kept going until the vee was a consistent height all the way along. Before I started it was cutting about a 0.15mm taper over 150mm, now it cuts about a 0.02 taper over the same 150mm near the chuck, which is good enough for me.

I solved the noisy gearbox by making a new belt drive to bypass it entirely. I made a couple of poly-v pulleys on the lathe as it was, and remounted the motor higher up. They are both stepped pullleys so I've got a 1.5:1 and a 4:1 ratio, in practice it will put a 25mm drill through steel on the 1.5:1 ratio on a slow speed from the inverter, so I have little use for the other ratio.

It's a 60 year old machine that most people would scrap, but with a little tinkering it's good enough for what I want to do now!

Pics

Welcome to the forum Oliver, that's impressive.

I've come across someone else who used their bed as a jig for its own regrind.

If it was my lathe I think I would try that.

Neil
10 February 2018 at 15:06 #340840
thaiguzzi
Participant
@thaiguzzi
"Like" button pressed.

Love the old MK I's and 1 1/5's…

Posted by Oliver Dudley on 06/02/2018 09:14:34:

I have a Mk1 Master that I bought about 12 years ago for 200 quid. I put a new motor and inverter on it and used it for bits and pieces. It was always very noisy (a couple of the gears in the headstock are very badly worn) and I struggled to make accurate parts over any real length. About a year ago I had a proper look at it and found the bedways for the saddle and its accompanying groove were badly worn, the saddle was almost 1mm lower on the left hand side!

I recut the 45 degree vee on the milling machine to make it the same depth all the way along, and DIY reground the saddle vee by making a sled that ran on the tailstock ways and a jig to hold a grinder at the right angle. I kept going until the vee was a consistent height all the way along. Before I started it was cutting about a 0.15mm taper over 150mm, now it cuts about a 0.02 taper over the same 150mm near the chuck, which is good enough for me.

I solved the noisy gearbox by making a new belt drive to bypass it entirely. I made a couple of poly-v pulleys on the lathe as it was, and remounted the motor higher up. They are both stepped pullleys so I've got a 1.5:1 and a 4:1 ratio, in practice it will put a 25mm drill through steel on the 1.5:1 ratio on a slow speed from the inverter, so I have little use for the other ratio.

It's a 60 year old machine that most people would scrap, but with a little tinkering it's good enough for what I want to do now!

Pics below:
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