Colchester Student Mk1 Won't Start

Result!

After an hour of fiddling, one good pry and it just popped out.

However, I started off by trying the knot method. This worked better than expected and it did hold the shaft, but even with me pulling it, there wasn't enough force to get it out

I did find a small bit of aluminium, but it was only 1-2mm thick, so didn't do much

I spent a while struggling and thinking what to do, pulling on the shaft occasionally, to no avail

Then suddenly I had a fantastic idea that I don't regret in the slightest. Not ideal, but i decided to get a nice screwdriver and stick it in the end collar and give it a gentle pry. And there was a quick pop and it came out. I didn't have to apply much force at all. I was quite surprised. I had tried with a smaller screwdriver but I wasn't applying much force at all as I am aware of the damage they can do. Luckily it worked out this time.

Then I carefully held a bit of leather around the collar as I pulled the shaft out, for one of the balls to still land in the chip tray. I have them both, so no loss yet.

I was interested to see that there isn't just a spring in there. Well there is, but it's not just a spring, looked different. Not quite sure. I don't want to mess with it as it worked before.

Took a bit of effort, but it slid out eventually

And now I have a very bare lathe. I could put it back together and have a lathe without feeds

Whatever this bit is called, is very dirty

In fact the whole thing is dirty. I will be cleaning for a long time

As for the holes, they are not as oval as yours Herman, but they are ovaled by less than 0.5mm, so I think that's good enough for my use. Maybe by the time i'm 50 I'll re do them. But Hopefully this lathe will have an easy life with me.

More gunk under, followed by more gunk

Anyway, time to get on. Apologies for the screwdriver sin, but it couldn't be helped and it got the job done!

It's bling time

You'll be able to sell your services as a Colchester Student Lathe Rebuilder after this Richard!

the two balls and spring are an overload clutch designed to let the shaft slip if the feed gets jammed, there should be, or at least there is on mine, a screwed plug that goes in the end of the shaft which adjusts the tension on the clutch.  actually I think there should be three balls, one pops partway out of each of the two holes, and the third one is between the spring, and the other two. now you have the lead and feed shafts off, good time to degrease the front of the bed, and get some paint on it!!

Phil

Edited By Phil Whitley on 04/08/2020 19:51:26

I am glad you got the shaft out. You can achieve anything with brutish force.

The dunno part is the wormbox. Check the holes in the sides for ovalness.

I agree with @Phil. Paint while everything is open.

Very long post ahead. But with good progress so I'll dive in

Started off by taking the Wormbox(thanks Herman) to pieces. I was a little scared by the spring, but it wasn't as strong as I thought it would be. So good news.

Absolutely filthy

Cleaned up the body

I decided that the lever at the bottom was very dinged up and not very nice to hold. And its about time I did some BLING. Got to show Herman how it's really done...

So I started off using a 600 grit belt on my belt sander, but using the unsupported belt section so it was slack and conformed to the shape. I used this to remove all the dings, then blended lots of surfaces.

Then I went to my standard green compound on a standard buffing kit wheel as a prepolish. This left a buffed surface, but not a nice shiny mirror surface like true bling should be

So I moved onto my proper buffing kit, starting with a Green 439T compound with a white close stitched polishing mop. If anyone wants a good source of polishing and bits, I find The Polishing Shop To be extremely useful for all my abrasive needs

From there I moved to a Blue P164 Compound with a Loose G quality mop

And finally, to finish it off, I went to a P175 compound with a Loose WDR quality mop.

So you tell me Herman. Do I BLING?

It took me possibly 20 mins, so not too bad, and I'm very happy with how it turned out. I may be tempted to do a few more handles.

So I stuck it all back together. I spun the little spun plug 90 degrees so that its using the less worn area now. It's now very clean, and I oiled everything

Then onto the rest, lots more cleaning. I have made more progress, but I'll finish the update later

Good blinging!! I am impressed!

I think that spring is broken and will not offer the correct stiffness, therefore locking force.

Anyway, back to cleaning. I was happily surprised how easily the whole assembly came to pieces

I started by cleaning a section just to see how easily the dirt came off, and I was happily surprised once again!

This shaft was held in with a set screw, which was easily removed with little effort

Then the next shaft was removed through a set screw that I thought was just an oiling hole for a bushing. Clearly not. This was very gunked up, but all clear now!

Here we have a few of the parts, still missing the handwheel shaft and the broken half nut, but as far as I'm concerned, a very simple apron. Only made less daunting through reading Hermans forum posts. So lots of appreciation there.

Then I popped out one of the tag holder pins and rotated the tag out of the way. This allowed me to go in and clean behind them since they had paint and gunk stuck, which meant they did not lie flat. More of a cosmetic issue. I bent them back flat and they look a little cleaner now, more like they're on the surface rather than having paint go up to them.

Then I removed the level/locking bar that stops the feed and screw cutting lever from being activated at the same time. So the machine does not pull its self to pieces. I have taken many pictures of the sizes below, since Hermans lathe was missing these parts. More to doccument them since Herman had a sketch of one that someone had made. Hopefully this helps someone somewhere someday!

I could almost have done with some of those hand garments too!

I did not measure the hole, but instead the shaft that goes through it. So it is always loose, so it is allowed to spin/turn

The thickness of the spacer is the only important feature, I am unsure if Herman knows of a spacer or something, but one is needed to put the bar at the right distance, and its thickness is as measured below. Fine tuning may be required (Pictures only represent half decent measurement, so take as you will)

Then, lucky me, I got to get the big calipers out. A lovely piece of equipment from a very lovely home. The men in Scarborough that I bought some tools from. I regretted not purchasing a few bits from them, so I asked if I could buy a few more and arrange a courier. This is weeks ago now, but I got the big vernier, slip gauge set and the larger depth micrometer. So It really came in handy here!

Overall length may not be critical, but it is good to see a full measurement.

Then, after cleaning all parts, I moved to reassembling everything

I figured out that the spacer that I made was slightly too thick, preventing the circlip from engaging properly. This is why the whole shaft came out when the new(original old) hand wheel got stuck and I gave it a yank. So I really had to take this all to pieces anyway. So, the spacer is now the correct thickness and the circlip fits in the slot very nicely. I also took good care to clean out the spaces where the wormbox fits in. This will provide better registration.

Edited By JasonB on 10/08/2020 10:58:42

So, onto the comments

Donovan, thank you. I would quite enjoy this as a job, but it takes me far too long for it to be profitable. Servicing would be difficult as I can't imagine anyone would post me their lathe. I'd like to see royal mail try to pick it up though, that would definitely break more than a few post officers backs. Either way, I do enjoy it so who knows what the future holds...

Phil, I'll have a look for the screw at the end of the shaft tomorrow. But, I don't want to paint it right now. I don't feel like I have the time to do a proper job. I want to do it once and perfectly. So, I will refrain and take it all to pieces again next summer. It seems much less daunting then since I know how to take it all to pieces and I'll know how the paint is to work with. Especially after these few parts I'm currently doing. Since I will be able to see if the finish is good enough from the spray gun, or if I need to invest in a spray gun and compressor. Parts can always be repainted, even if I take the time to try now. It's not wasted. I really enjoyed last weeks video, my Dad even watched bits over my shoulder since he was interested too, I'll get him hooked!


Herman, more blinging to come. I know my stuff when it comes to blinging, although I'm usually trying to bling hardened 01 tool steel in the shape of a knife... (turns out a lot more difficult to do)

The spring may be broken, but it has performed already and worked fine. Also with the years of abuse, perhaps a much stronger spring has been placed in your lathe when it should be weaker. We will never know. Unless I look at the manual...
I did not check the holes of the worm box for ovalness, but they seemed round to the eye. But I will measure them tomorrow. They seem round enough so I doubt that I will change them, but the measuring is always useful. I'm very happy you appreciate the bling. I will be blinging a few more handles as they look much nicer without the dings in. Mainly the apron handles since they're the most used. The handwheels can stay semi-polished since they are going to be well worn and show some character. Although who knows... I may bling at a later date! I hope the measurements are useful to you

All up to date now. Time for more painting and brazing, then even more reassembly, and finally some turning.

Thanks for the measurements Richard! Really means a lot to me. I will double check the new lockout lever thing's dimensions Brian made for me. The spacing collar is news to me. I had a thrust washer made, but its thickness is a lot less than the width of the collar.

Look at your spring's ends. Ends must always have the double kind of turns. Your spring has only one end with this. This means the spring will not seat correctly and will not function as intended.

I've been away in Hull for a little bit, but I'm back home now.

I'll sort the spring tomorrow. Do you have the measurements of your spring Herman?

Also, I need a bit of help.

I want to drill down the column of the leadscrew to help it align and provide some reinforcement, which can also be brazed in. I have a 17/64ths drill bit and a 9/32ths reamer, so I plan to drill down both parts with those.

However, I will then need a rod to go down it, since the lathe is out of action for actual turning, I can't make one fit myself. So the question/help is, what size rod should I buy for a 9/32ths reamed hole? Or perhaps the question is, will a 9/32th silver steel ground rod fit into a 9/32ths reamed hole?

I still have another week and a bit before my friend is free for me to go and braze, but the brazing rods and flux have arrived. So I have a week to drill and ream and fit whatever will go in nicely

Edited By Richard Kirkman 1 on 09/08/2020 20:07:08

A fascinating thread by all posters.

But why is this page the only one that has become narrow for both text and pictures. the text is easy, but the pictures difficult see. Anyone else similarly afflicted?

Howard

Hi Richard, what a great thread of your lathe restoration. Well done on all the problem solving and solution finding .. Herman, nice to see you again and thanks for mentioning this thread in yours, Phil, I subscribed to your channel and can't wait to binge watch every video, Howard, great info, thank you ..

My name is Mat and I live on the Westcoast of Canada .. I just bought myself a Colchester Student / Dominion a few weeks ago, probably the only one on the Western seaboard and like all of you, started with a general cleaning, wait, gotta take this apart .. clean .. yeah, gotta go one level deeper .. clean .. ah heck, might as well take her to bits and start over ..

Finding you guys is like finding long lost friends .. having a Colchester Student lathe in common is quite the uniting feature .. from all corners of this "blue dot" ..

I'm currently writing up my experience on the Colchester group page if anyone is interested ..

https://colchesterlathe.groups.io/g/main/topic/colchester_student_dominion/75772938?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,0,0,75772938

But I signed up here too .. so expect me to stick around

Cheers!

Mat

Yes, it's gone the same for me, Howard.

Hopefully the next page will go back to normal. No idea why

You said: "I want to drill down the column of the leadscrew to help it align and provide some reinforcement, which can also be brazed in. I have a 17/64ths drill bit and a 9/32ths reamer, so I plan to drill down both parts with those."

I do not have any idea what you are talking about? Perhaps a picture of what is broken will help?

BTW, I reported this page as I cannot read it ... it is a formatting issue somewhere.

I took something away rather than adding and all good now.

Herman, sorry if I didn't explain clearly, I mean to drill and ream down the shaft before I braze it, So it aligns. So the pin size is important as it will effect the fit

JasonB thank you for fixing the page.

Thanks for the message Mat, nice to hear someone else is here too. I have been on the colchester forum for a while, but only lurking. Your posts are looking very good so far!

Oh, you mean the halfnut, not the leadscrew.

I would not do that. I would clamp it in a short length of thick walled angle iron and then braze it up. IMHO you will never be able to align the centres of the two pieces unless you do it on a milling machine with a DRO.

It is only a shaft with no micro accuracy required.

Thanks @JasonB - now I can read again.

Yes of course, the half nut not the lead screw. Mixed my words up.

The shaft is actually very tight in the hole, so a very good alignment is required.

I'll take your word for it, however I would have thought that a 4 jaw with an 0.0005" indicator would have been able to get close enough to aligned. As long as the tailstock is aligned. Anyway I'll just braze it, I can reinforce it later if need be.

I've been painting and blinging today. Not particularly much progress as I didn't get the blinging finished.

The handle was deeply beaten up and had even more dings that you can't see in the pictures. It took a long time to file and get them out. I still have to remove all of the deeper scratches and other bits before I can polish fully

A while later on the belt grinder, the 600 grit belt was not abrasive enough, so I moved down to a worn 240 and then to hand files

Hand files and then back to the 600 grit gave a decent enough finish, but there are still some deeper scratches from filing that will need removing tomorrow

Almost at the pre polish stage. Not too much work to do tomorrow.

You said: "The shaft is actually very tight in the hole, so a very good alignment is required."

Look at how this guy uses the angle iron to align the two pieces and you will get the alignment. You can also add another piece of angle iron on the top if you like and make four holes in the angle to allow you access to the shaft where you can do the initial four brazing spot joints.

**LINK**

Do not look at how he smooth it out. Use your lathe to do that!

Yes, blinging wants a smooth surface to start from.... So I use the single cut file to remove all the dings, then onto the 180 grit up to 800 grit wet sanding paper. Or you can use a non-woven abrasive wheel on a pencil grinder for the very hard cast iron of the hand wheels.