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SnakeyJ

Colchester Bantam Lathe - stressful morning

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've been using my lathe a little of late, but was worrying this week as I was starting to see more chatter and some very poor finishes.

I decided to check alignment and brought a 10" length of 1" steel bar home as a test piece on Friday night.    The idea was to take a light surface cut over 6" and then mic this up to confirm any run out.   However the results were dire and very noisy as I moved further from the headstock.    I put a clean piece in and ran a dial indicator along the saddle - it was way out.

Having slept on it I decided to properly inspect the head today and stripped it down

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It all looked clean and well lubed inside, but then I decided to put a centre in check this - Houston we have a serious problem...

At this point the panic was setting in - I reread the manual and did a quick Google and decided to check the bearings.

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Apparently these Gamet bearings are seriously expensive £6-700 + vat for the pair!

 

A cup of coffee and a think - how can it be so bad? There's no obvious play in the bearings or spindle.     It has to be the centre?   I decided indicate the spindle nose.

Not amazing, but at least it's back in the right ball park.

 

Now I always wipe a Morse taper out before use and I've now given this a proper clean out, but still seeing a big alignment error 0.3-0.4mm with this center.   I get about half the error with another center that also came with the lathe.

 

I'm guessing that I have some damage to the spindle taper and may need to hone this out to remove any high spot's.    But is it actually possible to bend a center?

 

 

Sorry, excuse the duplicate video at below - unable to edit this out having started the post on my phone!

Edited by SnakeyJ
duplicate video

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I spent most of the night stressing over this, but finally decided it must be the spindle bearings that had worked loose.    The manual says these should be tightened so the end float is 1/10000" or 0.00254mm measured on the face of a flat centre in the spindle nose and 'the spindle remains free to turn by hand'   Rather subjective, but I checked mine and I was reading around 0.05mm on my cheap Chinese dial indicator, or 20x the specification.      I've decided to tighten the bearing up to 0.01mm making sure that it still had a good free spin on the spindle.

 

I then cautiously ran the lathe up through the gears to it's max 1600rpm - much quieter now and the eccentricity seems to have been largely removed.    I will borrow a proper dial indicator to double check this during the week, but the surfacing looks much better on a piece of bar stock, certainly sufficient for my needs and I will have another go at sorting out the head alignment. properly.

 

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Always a worry potential problems with gamet bearings. Glad they'd only come loose. 

Nice bit of fault finding. 

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Thanks Gina and Damian  - definitely getting there.     I've just lashed out on a proper 0.0001" dial test indicator Mitutoyo so should be able to get the bearings properly adjusted and then complete the levelling and alignment.

This engineering kit is almost as expensive as the astro toys - Hopefully I can turn a few projects out rather than just making piles of swarf and getting oil everywhere! 

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47 minutes ago, SnakeyJ said:

This engineering kit is almost as expensive as the astro toys - Hopefully I can turn a few projects out rather than just making piles of swarf and getting oil everywhere! 

Almost! It soon overtakes the astro gear :eek: 

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I reckon I could have had a very well equipped workshop with what I've spent on astro stuff but my priority went towards astro - sobeit!

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As a resident of Colchester (UK) since 2001, I found this thread a fascinating diversion to my morning. I had never heard of 'Colchester Bantam Lathes'. Decided I must do more research.

The original company was a pioneer in the industrial revolution and has a huge reputation for quality, but all production in Essex ceased in 1995 and was moved to Heckmonwike, Yorkshire where the company continues to trade as Colchester Machine Tools.  

At least production wasn't moved to the Far East, but if Parma Ham can't be bred in Suffolk and Champagne produced in Kent, how could this be allowed to happen?  It is also so unlike Yorkshire folk to accept anything not branded from the Ridings, or is The Only Way Is Essex as regards machine tools?

 

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20 minutes ago, noah4x4 said:

As a resident of Colchester (UK) since 2001, I found this thread a fascinating diversion to my morning. I had never heard of 'Colchester Bantam Lathes'. Decided I must do more research.

The original company was a pioneer in the industrial revolution and has a huge reputation for quality, but all production in Essex ceased in 1995 and was moved to Heckmonwike, Yorkshire where the company continues to trade as Colchester Machine Tools.  

At least production wasn't moved to the Far East, but if Parma Ham can't be bred in Suffolk and Champagne produced in Kent, how could this be allowed to happen?  It is also so unlike Yorkshire folk to accept anything not branded from the Ridings, or is The Only Way Is Essex as regards machine tools?

 

Hi Noah - I was posted with HQ 19 Infantry Bde, Goojerat Baracks, Colchester myself between '88-90 courtesy of the Army.   Without doubt the best and friendliest garrison town in UK and many fond memories of the town and surrounding area.   My only claim to fame would be entertaining and photographing Atkinson, Fry, Laurie and Robinson with the band of the 3 Royal Anglian, when they filmed the title sequence for Black Adder Goes Forth - Stephen Fry, Tony Robinson and Hugh Laurie were great fun, but Rowan Atkinson was very aloof and withdrawn.      Genius together as they played off each other as they seemed to make the gags up as they went along.

Colchester Machine Tools are still very much up and running and producing/exporting quite a lot of machine tools - Looks like they are mostly CNC driven now, but they still sell the traditional centre lathes Student and Master models - bet they cost a fair few shillings though.     I think the move to Yorkshire was part of the rationalisation of Harrison and Colchester under 600 Group Plc, both brands are still produced.

It's good to see that England is still producing and exporting some machine tools!

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1 hour ago, SnakeyJ said:

It's good to see that England is still producing and exporting some machine tools!

The 'producing' bit may be a bit misleading as most of the parts are made and sourced in china and the far east and have been since the 600 group was rationalised in the late 90's.

As far as I'm led to believe only the CNC side is still made in the uk and probably only constructed from a box of parts. 

I have a colchester student 2500 which is of 1997 vintage so probably chinese. It's a nice machine for the most but is more or less a harrison m300 in disguise.

Lathes.co.uk is a great source of info on the harrison and colchester lathes. 

Dalian lathes are a rebranded Colchester/Harrison for the far eastern market although a few have made it over here if you look round. 

Made in Britain is a dying breed I'm afraid. Very sad. 

Edited by mapstar

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Forgot the photos this morning, but a much better run at machining a test bar yesterday.    I was running this on 20mm black mild steel bar, so a little lumpy and naturally some chatter at 7" out from the chuck, but the results were considerably better and I was able to get a reasonable first pass on this.    Still measuring in metric with the micrometer, but I machined to 19.25mm at 20mm from the chuck jaws and ran out to 19.30mm at 150mm (170mm from chuck).   Quite a taper, but heading in the right direction. I should be able to resolve this with precision levelling of the bed and tweaks to the head alignment.     I will do the subsequent test cuts with a taper mounted collet chuck, which should give much more accurate alignment and see if I can source some truer bright steel bar stock.

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48 minutes ago, mapstar said:

The 'producing' bit may be a bit misleading as most of the parts are made and sourced in china and the far east and have been since the 600 group was rationalised in the late 90's.

 

Made in Britain is a dying breed I'm afraid. Very sad. 

This saddens me too, it would be nice to see some real production behind British badged brands, even if we outsourced the castings and heavier production.   The global economy has all but killed off UK production.    At least I know my Mk1 Bantam is 100% British built and powered by Brook's Motors of Huddersfield.    It may be old and worn, but will certainly see me out ;) 

Oddly enough a Dalian lathe did come up for sale locally - it looked well equipped and not a lot of money, but rather too big for my workshop and I'm not keen on another hernia!

 

 

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My 3D printers support "Made in Britain" so a fair extent.  E3D Titan extruder with V6 and Volcano hotends.  My Giant printer boasts a home designed and made heater block for very fast extrusion.  The control electronics is Duet3D (another British company) with the Duet WiFi board.  Plus I mainly use rigid.ink filament, also manufactured in Britain.  I don't know where the aluminium extrusion I use for the frameworks are manufactured but purchased from a UK supplier.  I admit to using Chinese silicone heaters for my printer beds but only because these would appear to be the best and I haven't found any British ones.  Of course, most of my astro kit was made in China.

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45 minutes ago, SnakeyJ said:

This saddens me too, it would be nice to see some real production behind British badged brands, even if we outsourced the castings and heavier production.   The global economy has all but killed off UK production.    At least I know my Mk1 Bantam is 100% British built and powered by Brook's Motors of Huddersfield.    It may be old and worn, but will certainly see me out ;) 

Oddly enough a Dalian lathe did come up for sale locally - it looked well equipped and not a lot of money, but rather too big for my workshop and I'm not keen on another hernia!

 

 

I had a boxford Industrial 11.30 prior to this and it was a nice machine.

Afaik Boxford/Denford still make these lathes albeit in metric guise at brighouse west yorkshire concentrating on the education market.

They are good machines and proudly still state made in Britain. They were very helpful when I phoned them.

I have steadily seen a rise in prices of the older colchesters as people realise the poor quality of the majority of the chinese stuff. Not all of it is poor though (600 group stuff) but you are close to the price of decent second hand stuff.

Edited by mapstar

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