Colchester Student Mk1 Lathe - Renovation Tips (Part 1)
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- čas přidán 2. 07. 2021
- This is a part 1 of sequel to 'Colchester Student Mk 1 Lathe - refurbishment' but in more detail and with more technical content. It also invites feedback from anyone who has undertaken a similar project. Topics covered include: Levelling, gear train shear pin, interlock mechanism, auto-cut off.
I have produced another dedicated video on levelling the Colchester Student Mk1 which supersedes what is covered here in point #2. I recommend viewing: "Levelling Colchester Student Mk1 Lathe" for a better description of this topic.
• Levelling Colchester S...
For an overall summary of the refurbishment as an introduction to this video see my video "Colchester Student Mk 1 Lathe - refurbishment" • Colchester Student Mk1...
With appreciation for music: 'Pastoral' - Asher Fulero - used with permission
#colchesterlathe #latherenovation #colchesterstudent - Věda a technologie
I spent today merrily degreasing a Mk2 Student. Your videos have cleared up quite a few questions this process has raised. It also made the inevitable crash I would have had with the automatic apron feed and cross-slide feed, far less likely! Thanks for sharing, exceptionally well thought out and well put together. You’re a great source of information, keep posting for God’s sake!
Good to hear that you found something useful. I read somewhere that the Mk2 has a higher standard of headstock gearing which is quieter at high speeds (and an induction hardened bed as standard?).
Yep its not realy loud on 1500rpm
I dont think the induction came as standard but mine has the sticker on the tail that say it did
My apologies that my previous comment went off prior to being completed, Fast fingers and a slow mind I think, anyway I appreciate your efforts to detail the restoration of the Colchester Student Mk 1 as I have just acquired a 1963 gap bed version which is in need of a restoration. Interestingly my one as a different power feed setup in that it has two separate levers for the engagement of the longitudinal and transverse feed.
H Steve, Interesting! I haven't seen such an arrangement on a Colchester. If you haven't already, you might glean some information from the www.lathes.co.uk website. Hope you enjoy restoring and using your machine as much as I did.
Great video on the mig
I suspect the mild steel shear pin might be a mistake. Mild steel is ductile and will bend rather than shear and damage the flanges. HT bolts are more likely to shear. If you are still concerned the HT bolt is too strong a scribe line on the bolt at the point where it needs to fail works. You can test potential shear materials by placing in a vice and belting it with a hammer. If the material bends, avoid. I’m no expert, dumb farmer, but have broken fair share of shear pins. Thanks for the video. Colchester Student lathes are beautiful.
Thanks Rupert for your interesting comment. There is certainly nothing like practical experience!
I wonder if it matters whether the two flanges and the shear pin hole fit snugly. I can certainly imagine the kind of issue you mentioned if this is not the case - like loose scissors, or my old guillotine!
@@Workshopfriend You would think so but it is not my experience. I have damaged some quite good flanges with mild steel bolts where it should have been a shear pin. Amazing how the mild steel bends and stretches and elongates the shear pin holes. Amazing.
Great vid
I got me a mk2 two days ago
Cant wait to get back to operation mode
It is runing but rusty and needs care
I am sure you will enjoy getting it running. Hope the rust isn't too severe - usually looks worse than it is.
Hello and thank you for your interesting video: I would like to ask you: is it easy to remove the screws that connect the base to the stand? Because I would like to know if it is possible to install a motor at the same level as the lathe support surface and place it on another table higher than the standard one like yours; thanks in advance for the reply !! Alberto.
Hello Alberto, By base, I assume you mean lathe bed. Removal of the bed from its stand is relatively easy. There are 6 or 7, 1/2 inch socket head cap screws which are accessible from the underside of the coolant tray. Can't you raise the level of the lathe by sitting the stand on raising blocks as I did and keep the existing motor location? If you want to do accurate work I think the support (stiffness) the stand provides is important. Raising blocks between the existing stand and the underside of the bed would need to be accurate to maintain flatness. Just some thoughts for you.
@@Workshopfriend Thanks for the answer: I am waiting for a Colchester Bantam lathe, but in any case I am ready if a Student like yours should happen, for which I am forced for reasons of space to replace the original stand and bring the engine up; with the Bantam 1600 everything is easier but it is difficult to find compared to a Student, and therefore I am ready for any eventuality! Fingers crossed! Thank you for your answer! In addition to being flat, the new stand has 4 adjustable feet!
Hey ! we have almost the same lathe. Has spent almost 70 hours aligning the lathe and finally succeeded. Do not know what you mean by fixed legs really but you should adjust on all 6 legs and make sure that the same level at the front at the chuck and at the back at the tailstock. If you have twist in bed than its almost impossible to remove twist by adjusting this legs so you have to put some shims between stand and bed at tailstock end. For headstock aligment u need losen 4 bolts and adjust by 2 adjusting screws at back of the headstock.
Hello Metin, Thank you for your feedback! It is good to hear that you are embarking on a similar project. 70 hours is a long to spend in levelling. Well done for persevering!
With regard to the feet perhaps I have an older design of stand - hence the differences. I can imagine that shimming of 6 or 7 mounting lugs under the bed might be necessary in extreme circumstances. Thanks for that hint!
Yes, the headstock alignment facility is a great asset and easy to use with a dti and test bar.
Hi. Thank you for sharing. I have recently bought a MK1.5 Colchester that i hope will be a big upgrade on my Super 7. I will definitely be following your videos since i am also planning a rebuild/restoration on the lathe.
I have one question. Do you think that the safety feature on the for the feed screw is designed to be used with lathe stops on regular basis or is it not just a safety feature that should be only used if there is a overload to prevent damage? I mean is it designed to be used regularly?
Thank you for the tips.
Good to hear you are undertaking a similar project. Thank you for your good question. The manual refers to the "knock-off" function as being a safety "safety device" with a factory pre-set of 350lbf end force (I assume on the carriage). Although this can be reduced (and I am sure mine trips at less force than this) it seems like a lot of load to repeatedly subject the rack and pinion to at one point. Personally I would prefer to use it as a safety feature.
I wonder if anyone has any thoughts on this.
I want to find a Student in the States to learn on, what a quality tool. I watched the factory promo and #3 must be one of the student safety designs that they speak of. I would think that the jack oints would typically be disengaged from the floor as, assuming the 3 feet are located for proper weight distribution, it is impossible to transversely twist a 3 point plane. I learned that from watching someone perfectly level a fixture table.
You probably know that in the US this lathe is normally referred to as Clausing Colchester. There seem to be plenty about. I have to admit I haven't reached a firm conclusion on the way that levelling of the lathe should be achieved with these 5 potential points of contact with the ground. I didn't have time to adequately investigate, but hope to when I return from overseas - this time with an engineer's level. As I mentioned in the video the jacking points didn't seem to induce easily measurable twist in the bed due the redistribution of load bearing from three points to two if I deliberately jacked up to the extreme. I intend to check this more precisely.
I agree that the three feet seem to be located for even load distribution. However, nothing is truly rigid and the weight of the lathe could induce twist in the bed. Even more equal load distribution can be achieved on a 'stable' floor surface with added support from the jacks. I found that I needed to use the jacks to stop rocking as I used rubber pads under the feet. More careful measurement of bed twist is required. Thank you for your feedback!
@@Workshopfriend I was actually wonder about the Clausing part of the name as I saw another restoration of one that resembled a student put didnt carry that embossed label. I will be looking for one along with a vertical mill to restore. I have no experience with machining yet but do have woodworking knowledge, engineering designer training, and have restored several Shopsmith tools. Thanks for the content!
Great video. Very interesting. I noticed a comment re the shear pin , aluminium? Supplied by the manufacturer, hmmm interesting. Not that I have ever had a pin shear on my student.
Thanks! I suppose it depends on what kind of aluminium alloy vs which steel. The foul up that damaged the drive chain on my lathe was, I suspect, a result of the interlock mechanism having been left out after a strip down.
12:48 Your reversing switch is in a funny position ! Usually 12 O'clock for reverse and 3 o'Clock for forward.
Yes, you are very observant! This is because I removed the reversing switch which is not required with a VFD.
@@Workshopfriend True. That's WHY I DIDN'T GET A VFD !
Dad used a static converter - it went bang and I never liked it.
Bought a 3ph diesel gen this year. Doubles up as emergency backup power for the house - or portable! power. My channel Machining by Mike shows it. My reverse lever works !
I decided that the machine was fitted with a lever like that so I was going to keep its functionality - instant reverse !
Hi, watching your nice video i have other 2 questions (thank you for your patience): 1) The belt of the Colchester MK1 was plane ? Not a V-type ?Is it easy to find a replace in case ? 2) The back cover of the lathe, that is place over the gears with 2 nuts that you say well made...is it in plastic or sheet-metal ? Thank you in advance for your answer to me, Alberto.
1. By the time the Colchester Mk1 came along flat belts were no longer used. Even before this time V-belt and geared headstocks were common. If you have a Colchester lathe which uses a flat belt it must be from an earlier period. Could it be a Master 1930-39? See lathes.co.uk website. Flat belts now are usually continuous (no join), but in those days canvas belts with metal joiners were used. The bely could be cut to any length. There are suppliers of these belts still around but it may take some searching. Depending on your layout you may or may not need a joiner. My first Drummond lathe had this arrangement.
2. The gear cover on machine is aluminium casting.
Hope this helps.
@@Workshopfriend Super thanks for your comprehensive answer, I ask you this info to try to avoid or anticipate any problems. Thanks again, Alberto.
Looking at the apron at 1:50, what stops the power feed lever dropping further than that ? Mine drops quite a way !Also, if you fully unscrew the engagement lever knob, I believe there's a compression spring in there - no sign of one on mine and the adjustment is too easily turned :(
Underneath the apron behind the power feed mechanism tray there should be two roll pins to limit the downward and rearward travel. Look for their holes. Yes, there should be a spring in the mechanism to provide resistance. I can't dismantle to show you since I am not near my workshop. You could look at the parts catalogue and estimate the proportions.
@@Workshopfriend See you on e-mail !
What's the method of lubricating the apron gearing & wormbox ? There seems to be a lot of places that need lube - is any of it it immersed in oil (I believe some have oil in the aprons (with or without sight glasses!)
It seems you also may have been reading the excellent write-up in lathes.co.uk(?)! [See my comment below re the apron which was also from that source] The lubrication is provided through two of the oilers on top of the saddle. There are channels to get the oil to the various places in is required. The Mk1.5 had the enclosed apron with an oil bath.
@@Workshopfriend Is that the one I sent a few corrections about ;)
I would remove your steel pin and replace it with an aluminium one. It should be aluminium. It's meant to break if the saddle crashes. If it is too strong, something else could break instead. According to my paperwork, they came with aluminium shear pins. You could buy more from Colchester.
Thanks for your response. I haven't seen any definitive information on the shear pin. If you have a handy source I would be interested if you would kindly point me in the right direction. Online forums seem to contain a lot of contradictory advice. My e.mail address in workshopfriend@outlook.com. Thank you!
How did you lubricate the gears in the apron?
When I re-assembled I used a general motor oil - assuming yours is the open type saddle. The next version had an oil bath using the same oil as in gearbox.
From memory all important parts of the saddle mechanism are serviced by two oiling points on top of the saddle via channels and holes in the castings. Note: If grease has been mistakenly used you will probably have to disassemble and clean out the channels.
@@Workshopfriend My apron is is the open type. It has a small bathtub type sump that holds oil and has a sight glass to check the level of the oil.
There is a copper tube that goes from the sump to a manual pump that oils the bed ways and cross slide ways only.
I assumed the gears ran in a oil bath due to the presence of the sight glass but they do not.
I cleaned the channel and seen that the holes only take oil to the shafts that turn.
I wanted to make sure I was not overlooking something before I put the apron back together.
I will use a light oil on the gears and worm gear as needed. Thank you.
Congratulations on having a slightly later model!
@@Workshopfriend Thank you.
Hi, i am from brazil and i need same parts for a lathe like your ,van you help me?
Hi Frederick. In this video I referred to one if the gears in the gearbox; in another to the taper turning attachment. Which video and parts are you referring to?
@@Workshopfriend hi,need onde of this parts or the drawing
21810- clamping handle
7712- leadscrew half nut
7562- leadscrew nut
Hi Frederico. I have located your parts in the parts list. Unfortunately the leadscrew eccentric nut cam and and the half-nut are not accessible without some major dismantling (and I am here where this machine is located for just another couple of days until Dec). I wonder if anyone else has a saddle off their machine and can give some measurements? I recommend you ask on the Colchester Lathe forum colchesterlathe.groups.io/g/main
I have easy access to the clamping handle. If you write to me on my e.mail address I will happily measure the dimensions and send them to you. Hope this helps.
Where are u if not UK ?
I am normally based in Pakistan.
@@Workshopfriend Interesting - a bit of a surprise !
Why not just convert using a VFD inverter solves all your RPM problems
Hi Jeremy. I did fit a VFD, and it has been extremely useful. One issue that should be considered is that the headstock lubrication (and in particular, the important headstock bearings) require the input shaft to be running at a fair speed - see the next video Part 2 which mentions this czcams.com/video/pxj5Rp3MolA/video.html
Using a VDF at low speed for long periods of time may compromise the effectiveness of bearing oil supply.
You keep calling it a ''MK1' more widely known as a 1.5 as the proper mk1 has a different apron and different style gear knobs.
You may be right. However, I thought that the Mk1.5 had the fully enclosed apron with the gears running in an oil bath with or without an oil level sight-glass.
I replaced my shear pin with a roll pin.
I didn't think of that. Not sure how cleanly a roll pin would shear given that it will be hard. I did some comparison of strength with solid m/s pin both 4.5mm dia: Double shear strength of roll pin 15kN (3,500lbf); double shear strength of solid m/s pin 9.5kN (2,100lbf).
@@Workshopfriend I did not know the roll pin was that strong.
When I accidently crashed my Colchester I found a sheared roll pin. I assumed it was factory installed.
The noise it made was very loud meaning if was in a bind.
Someone must have replaced the original pin.
Also it was not the pin in the drive gear that sheared. It was a smaller roll pin on the input shaft of the gear box. I will have to take a look at where it is located exactly as I do not remember.
Anyways, could you make a mild steel pin with two grooves to take less force to shear if you crash the lathe.
The grooves would need to straddle the external diameter of the shaft and the internal diameter of the gear.
After learning the force required to shear the roll pin I am having second thoughts about using it now.
Some newer lathes use plastic idler gears to save the lathe so it does not have to be that strong I would assume.
@@Workshopfriend The roll pin that broke connected the feed shaft to the output of the feed box. Just took the apron off to clean it and remembered that roll pin breaking.
If everything is as it should be I am sure that the shear pin at the first gear of the gear drive train should shear before the roll pin 'downstream.' I wonder if someone has bodged the shear pin at the gear e.g. I don't think a high tensile bolt should be used.
With a little geometry, using the most advantageous gear ratio through the gearbox, and some data sheets it should be possible to design a shear pin which will shear well before overloading the roll pin ie say 50% of that max torque.
@@Workshopfriend I will take a look at the drive gear shaft and see what the pin is made of.
no music
Thanks for your feedback. Will bear it in mind.