# Cromwell S800 Mk3 lathe



## RodF (Apr 17, 2014)

I am just finishing up a 3D printer design and build and recently finished a CNC hot wire foam cutter design and build.
Have been looking around for a new lathe for a while now and an unfinished project came up on our local buy and sell site. I've taken a risk and bought it so now I am committed to finishing it.  Hopefully I will not have to make too many new parts.
Here is a photo of what it looked like before disassembly and its current state. If I can get it looking half as good as Valleyboy101's I will be really pleased.


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## valleyboy101 (Apr 17, 2014)

I'm sure that you can make it look as good or better than mine.  Yours looks about the same as mine when I brought it home and yours is well on its way.  What accessories did you get with it?  Mine is missing the steady and follow rest and most of the change gears (apart from the set it came with) but all the main parts were there and I have the material to make the change gears.
I learned a few things with the work on mine so if I can be of help I would be pleased to do so.  They are a rare machine in these parts.
Good Luck,
Michael


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## RodF (Apr 22, 2014)

Got the lathe home.  More damage than I hoped for but I can live with it.  Some missing parts main one the cross slide power feed shaft.  Also the roller door and the steadys and collets. The guy I bought it from has only had a bit of a look for them so am hopeful he still has them and can find them.  Have offered financial reward if he can find them.  Only the main drive motor is in place so will need to replace with 3 phase motor and inverter drive or a servo drive.  Interestingly there is a spare headstock shaft!  No chucks but a chuck mount and a face plate for drive dog but no centre? Lots of newly chromed parts though so it should look nice. Well I have a good challenge on my hands to make it into a usable machine.


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## RodF (Jun 2, 2014)

I have been trying to get the guy who sold me the Cromwell to find the missing parts.  So far he has come up with what are probably the most important ones, the steadies and the roller door.  I am going to see him this week and hopefully find some more parts.  However I have enough to do a full rebuild.  I think I have a belt supplier in the US  http://rubberproducts.jasonindustri...-type-400-endless-woven-flat-belts/item-10009  however they are only .035" (0.9mm thick) but at 1 1/4" wide it should handle the fairly low power requirements.


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## RodF (Jun 2, 2014)

Took out the original DC drive motor.  The original ac motor and generator were missing.  These will be replaced which a 3 phase motor and variable frequency drive or a servo drive.
Am panel beating the door parts.


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## RodF (Jun 4, 2014)

Started with the bed. This is the the dirtiest part to prepare, lots of gun wash and grease remover sorted it out.  I am spraying it with 2 part polyester undercoat then finishing with the original light blue spraying enamel.


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## RodF (Jun 5, 2014)

I've stripped back the stand ready for undercoat, it just needs a good wash down with degreaser.


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## RodF (Jun 6, 2014)

Got undercoat on the stand.  I ordered a 1 1/4" wide 59" long continuous drive belt the other day, today the penny dropped.  The drive system is designed to have the belt spliced in place.  However all is not lost as I think I can make an arrangement of idler wheels to guide the belt through a single belt way.  More to come.


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## mattthemuppet2 (Jun 6, 2014)

wow, looks like you're making cracking progress!

OT - I lived in Upper Hutt for a bit over a year several years ago. Worked at AgResearch until they shifted us to Palmerston North. I preferred Palmerston North as a town, but seriously missed the hills outside the Hutts!


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## RodF (Jun 7, 2014)

Got the enamel onto the stand and bed.  Not a bad match with the original, could have been slightly lighter blue but I am happy with it.


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## drs23 (Jun 8, 2014)

Looking great! Please keep us updated and keep the pics coming!


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## RodF (Jun 12, 2014)

Prepared more parts for painting.  I'm doing the biggest parts first. Also took the auto feed reversing gearbox off and cleaned it. The fits on this machine are really nice and the machine seems to have little wear just signs of abuse (my rescue lathe;-).


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## RodF (Jun 13, 2014)

Got the undercoat on.  A couple of parts will need to harden and be turned over to paint the other side.  You guys will have to excuse me if this gets repetitive but I want to document the complete build.


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## RodF (Jun 13, 2014)

Decided to power the lathe with a 750W servo drive in velocity mode.  Ordered it from here http://www.aliexpress.com/item/AS80-750W-AC-Servo-Motors-and-driver-AS80-30-024E25/1678633496.html It is a 3000 rpm motor so I will reduce the pulley size to keep the spindle max speed at 2000rpm. Am hoping to duplicate the original RPM display in some way


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## RodF (Jun 13, 2014)

There are a few parts missing from this lathe, fortunately I have all the castings except one of the sliding door guides which I can fabricate.  One of the parts missing is the gear on the end of the spindle, I will make the parts myself.
The gear is 16DP and I am assuming it has the same number of teeth as the output gear on the reverser ie 25am also assuming it has a 14 1/2degree PA but will measure that.  It has a 1/8" keyway so I have ordered a keyway broach off Ebay.  I will also be making a couple of 30T back gears for metric threading and whatever I need to do the thread on a chuck backplate and faceplate.


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## samthedog (Jun 14, 2014)

Nice work Rod. While living in Norway I have been frantically buying machines as there is a huge selection of European machines here. I noticed while living in Queensland that machines like your Cromwell were very rare. I knew a number of shop owners and all their machines were Taiwanese. You're doing a great job and it's wonderful that you found a keeper.

Paul.


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## RodF (Jun 14, 2014)

samthedog said:


> Nice work Rod. While living in Norway I have been frantically buying machines as there is a huge selection of European machines here. I noticed while living in Queensland that machines like your Cromwell were very rare. I knew a number of shop owners and all their machines were Taiwanese. You're doing a great job and it's wonderful that you found a keeper.
> 
> Paul.


 
Hi Paul
Thanks for your kind words, early days yet though.
I was looking at Chinese machines but these older machines have artistry in their castings.
Rod


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## RodF (Jun 15, 2014)

Prepared the head casting for undercoating.Took out both bearings and the pulley. I was a bit apprehensive about this but it worked out fine. I took the pulley out so I will be able to fit the continuous belt I have on order, also was able to give the whole thing a good clean out.
Also able to undercoat the reverse sides of the parts I did the other day.  Quite a bit of masking to be done.  The lathe has had 2 colours applied to it since it's original blue. which is still quite soft. It is early winter here but a very mild 13 Deg C low, however I am going to cook these smaller parts in my heater box for a more rapid cure.


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## RodF (Jun 15, 2014)

Got some top coat on today.  A couple of small runs on the head so I will sand and repaint as I do the other parts.  Still another 10 or so parts to do, mostly small though.


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## RodF (Jun 18, 2014)

More of the same . Painting the reverse sides of the parts done the other day and repainting the head.  The head repaint didn't go so well with some reaction with the earlier coat.  Just need to spray lighter coats at first so the thinners flashes off before it can react with the underlying coats.  Preparing more parts. Learnt about hammer screws, the little rivet like fixings holding the naming plates on.


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## RodF (Jun 19, 2014)

Yet more painting.  I used epoxy undercoat this time as I had some mixed up for another project.  I have used this a lot before but I find the polyester undercoat more forgiving.  However I think the epoxy is tougher.  The keyway broach arrived today.  By the time I have finished the painting I should be able to start making the missing parts.


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## RodF (Jun 22, 2014)

I'm starting to think about reassembly now most of the painting is done.  Working through the gearbox assembly.  I need to make a 1/2"x 1" bearing for the left hand gear ratio shaft.


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## RodF (Jun 22, 2014)

I am missing a bearing for the end of bottom shaft in these pictures.  It looks to be bronze in the picture of a complete machine from the lathes.uk site.  It looks to me like it also needs a retaining thrust washer on the inside.  Probably 1/8" steel.  Hopefully Valleyboy101 will come to my rescue here.


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## RodF (Jun 22, 2014)

This is the kind of arrangement I have in mind for the bearing and how to retain the shaft.


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## RodF (Jun 24, 2014)

Servo and controller arrived today.  No instructions or D25 pinout, but how hard can it be:thinking:  From the online documentation it should run in velocity mode with just a 50K potentiometer.  Most likely Mach 3 documentation will sort me out.


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## RodF (Jun 24, 2014)

Of course I emailed the Chinese company I got the servo and drive from about documentation.  They came back very quickly with a request for my email so they can send the manual.  That should be problem sorted)


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## RodF (Jun 25, 2014)

Made the bush for the gearbox shaft.  One of my friends gave me a piece of bronze and I got a second hand 1/2" reamer.
Got a good fit but the shaft must be slightly bent as it is a wee bit tight in one quadrant when rotated.
I still need to drill the oil hole and make an oil groove.  Then make the thrust bearing.







Took the pulley off the original motor and it is a nice fit on the new one just needs a bit of adjustment to the key.
Instructions arrived for the servo controller.


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## RodF (Jun 26, 2014)

Working on the next lot of parts for painting.  The apron and cross feed drive rod end support casting has been smashed then brazed up at some point.  Put filler on it ready for painting.
I wasn't happy with the first lot of filler, took it off and used a better quality product.
Also managed to straighten the gearbox shaft to free up its rotational movement.


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## RodF (Jun 26, 2014)

Waterjet cut some rubber washers for the front panel fasteners.  I tried one out and they work really well to rubber isolate the panel)





- - - Updated - - -

The previous owner had the the detail parts chromed.  That meant the tailstock locking arm didn't fit anymore so I opened out the hole in 0.1mm increments till it fitted. This tailstock differs from others I have seen in that the barrel seems to be shorter and the adjustment mechanism is on the back.  Both the adjustment mechanism and the T nut screw/drawbar are missing so I will need to make them.


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## samthedog (Jun 27, 2014)

Great work Rod. I am really enjoying watching you bring the old girl back to life.

Paul.


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## RodF (Jun 27, 2014)

samthedog said:


> Great work Rod. I am really enjoying watching you bring the old girl back to life.
> 
> Paul.



My pleasure Paul, it is giving me a good time.

Rod


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## RodF (Jun 27, 2014)

A set of 16 DP cutters arrived from China today. All set to cut back gears now.  I dug out my dividing head, now have to refamiliarise myself with its operation because the last time I cut a gear was over 10 years ago. I am just waiting on the drive belt now.


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## Don B (Jun 27, 2014)

RodF said:


> Working on the next lot of parts for painting.  The apron and cross feed drive rod end support casting has been smashed then brazed up at some point.  Put filler on it ready for painting.
> I wasn't happy with the first lot of filler, took it off and used a better quality product.
> Also managed to straighten the gearbox shaft to free up its rotational movement.




Your doing a wonderful job on the restoration, that will be a very nice looking machine when your done and be a lathe some character, well done....!)


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## RodF (Jun 28, 2014)

Don B said:


> Your doing a wonderful job on the restoration, that will be a very nice looking machine when your done and be a lathe some character, well done....!)



Thanks Don.  I am getting to the more difficult part of the restoration now, the stripping and painting is pretty straight forward. I have a few more parts to paint but am nearly finished.  I have nearly procured all the materials and equipment to finish it.  First job is to get this gear cutter holder trued up and turn a new shoulder for the cutter as the one on it is undersize at 0.962". I have to get a new drawbar for this mandrel as it is imperial thread.  Most of my tooling is metric so I am needing to get some more taps and a die or 2.


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## RodF (Jun 29, 2014)

Cut shoulders in the arbour for the gear cutter and slitting saw.  As you can see I did it in situ on the mill/drill.  A bit unconventional but it has to be true.


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## JimDawson (Jun 29, 2014)

Nice setup.  Unconventional is not a problem as long as it got the job done.  In my opinion, as long as the parts come out the way you want them, it makes no difference how you get there.


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## f350ca (Jun 30, 2014)

I made the final cut on my last mandrel the same way, but simply clamped the tool holder in the milling vice. The gear cutter sounds different running with zero runout.
Greg


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## RodF (Jul 1, 2014)

Undercoated some more parts, quite a bit of masking required for these.  Once they are done I can start  reassembling the gearbox. I am still waiting on the drive belt which I need before I can reinstall the spindle.


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## RodF (Jul 7, 2014)

Sanded the parts and put another undercoat on them. The two biggest back gears were also painted so they got some undercoat too.  Made collars and keyways for the slitting saw/gear cutting mandrel.  Now I am pretty much tooled up to make the back gears and cross slide drive shaft.


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## RodF (Jul 7, 2014)

Nice day for painting.  Just the louvre doors and steadys to paint now.


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## RodF (Jul 10, 2014)

Have started to reassemble the lathe.  I need to make the apron clamps to continue.  They don't seem to work like jibs, they seem to be  sliding fit.  So i measured it up as best I could and started machining.  Results so far are promising and I will fit each one as I go.  Starting to get a feel for how she will look with the tailstock on (but not fitted), the chrome will be pretty bingy.  Drive belt could be months away so I am going with plan B which is splicing.  Any tips welcome.


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## RodF (Jul 10, 2014)

Got the apron retaining blocks drilled and tapped.  The are a nice fit just a little tweaking to do.  I can feel the bed is slightly more worn closer to the chuck (as you would expect).


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## RodF (Jul 11, 2014)

Had to chamfer the corners of the apron retaining blocks to clear the drive screw.  Carried on with assembly and discovered I need to make a fitted key for the right hand feed drive.  I have some 1/8" gauge plate for it and will also cut some for the top slide jib I need too.


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## RodF (Jul 11, 2014)

Made the key.  Am getting a bit ahead of myself here.  The apron action feels too tight so I will go back and get each part nice and smooth.


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## drs23 (Jul 11, 2014)

It seems to be coming along swimmingly. Thanks for the update and please keep us posted with your progress. With pics of course. )


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## RodF (Jul 13, 2014)

Thanks Dale, I'm on a roll, however work will intervene at some point soon.
Started on the drive gear on the end of the spindle.  The poor old Myford is going to be the instrument of its demise.  I might do it up too before I sell it.


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## RodF (Jul 14, 2014)

Cut the gear.  Went well till we had a power cut while I was doing the last tooth.  Had to wait an hour to finish it.  Now I have to make a press and insert to cut the keyway.


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## RodF (Jul 15, 2014)

OK so I need to make a broaching press.  Nothing fancy as I only need to do a few.   Here is progress so far.  Still need to make a hole in the base plate for the broach to pass through.  I have a large bar to drive it with.


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## RodF (Jul 15, 2014)

Finished off the broaching press.  Last job was to drill the hole for the broach to pass through.


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## RodF (Jul 15, 2014)

Made the broaching guide. A bit tricky getting the depth right but it came out fine.





- - - Updated - - -

Did the broaching.  It required quite a bit of force but I was being pretty careful.  Put the shim in and did the second cut, it was a little bit easier.  Got a good result, just need to drill and tap for the grub screw.


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## RodF (Jul 18, 2014)

Got the spindle in and the gear on the back of it.  That meant I could mount the back gear housing.  I am keen to get the servo running about now, so I can start on the motor mount.  I have some ideas for duplicating the original control system and also a rpm gauge. This is where the 3D printer will be useful.


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## RodF (Jul 22, 2014)

Sorted out a problem I had with the left hand apron driver.  As I got it the shaft was bent almost 45 degrees.  I straightened it using force and heat but it was still seized solid. Tonight I finally got it apart and can now have the dial chromed along with a few other parts.

Most of my time on the Cromwell project recently has been researching the servo controller setup.  The servo controller needs to be operated in velocity mode which needs an analogue input from a differential mode OpAmp.  The driver instructions are pretty good for a Chinese product, but it has been a fairly steep learning curve for someone like me who hasn't had a lot of experience with this stuff.  However I think I have it worked out now (but will run it past a qualified electronics engineer).


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## RodF (Jul 26, 2014)

Unfortunately the base of the top slide is damaged.  There is enough left of the T nut hole for nut to have some clamping effect though and I think that will improve with some sort of rebuilding.  My thoughts at this stage are to shape a piece of steel to fit as well as I can get it then screw it to the slide base and fill the gaps with silver solder.  I do have a stick welder and presumably could do something with the correct welding rods.  Any thoughts on this would be appreciated.


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## Marco Bernardini (Jul 26, 2014)

RodF said:


> Unfortunately the base of the top slide is damaged.



Damaged? It looks *chomped*!
There must be huge beavers, in your surrounds… :biggrin:


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## RodF (Jul 26, 2014)

Yep, it certainly has been abused.  Hopefully it will have an easier life from now on.  Still I think there is enough metal left for some clamping force and hopefully I can effect some cosmetic improvement as well.  I will leave the damage on the end as it will be mostly covered by the slide.


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## RodF (Jul 27, 2014)

Made the connector bolt for the T nut and lock arm on the tail stock.  Tested it and it has a really nice action.  Now to make the adjustment screw.  This is the early style of tail stock, the later type looks to have more throw and better adjustment method.


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## RodF (Jul 30, 2014)

Made an adjustment screw for the tailstock.  Overcooked the die tightening so it is a bit loose so will probably make another one.  Will cut a slot for screw driver and lock it with a custom washer.  The front stud also needs replacing.


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## RodF (Jul 30, 2014)

Got a length of 5/8" silver steel to make the replacement cross slide drive shaft.  It is a nice fit, I need to cut a 1/8" slot in it for the drive key.


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## RodF (Jul 30, 2014)

The drive belt I ordered turned up today, so it is back to drive plan A.  This will involve at least one idler and I think a new motor pulley. The belt is manufactured as a continuous loop, not spliced so it should be strong and vibration free.


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## RandyM (Jul 30, 2014)




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## RodF (Jul 31, 2014)

Thanks Randy
Congratulations on your 1000 posts.
Rod


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## RandyM (Jul 31, 2014)

RodF said:


> Thanks Randy
> Congratulations on your 1000 posts.
> Rod



:laughinghard: Rod, I hadn't even noticed. Thanks for pointing that out. Keep up the good work, sure looks like you know what you are doing. Thank you for sharing your fun.


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## RodF (Aug 5, 2014)

Making another top slide retaining bolt.  I need an edge finder to mill the flats.  Am working on an electronic one, the first version not 100% successful.  I need to breadboard it so I can swap connections around.


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## RodF (Aug 15, 2014)

Work has been interfering with the lathe project over the last couple of weeks and it is too cold in the workshop at night.
6mm keyway broach arrived from China.  Despite protection in a wooden box it still arrived broken.  I have had a lot of items from international destinations and this is the first to be damaged.  All is well though as it is a draw broach and cuts the full depth in one pass. There is still plenty of material to modify it for my broach press.


Independent 4 jaw chuck also arrived.  This will also need to be modified to fit the adapter plate.


One of my colleagues at work gave me an old meter which I can adapt to an RPM meter.  Will mount a new voltmeter unit inside the housing and get new scale artwork.


Original had dual scale for the back gear speed.  I will duplicate the original cast housing with a 3D printed part.


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## RodF (Aug 16, 2014)

Cut off a piece of 65mm free machining aluminium bar for the motor pulley.  Did a bit at a time with other jobs in between, chucked it up and faced and drilled.  Next to bore for the motor shaft.


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## RodF (Aug 16, 2014)

Finished off the pulley.  Of course I had to make a broach guide.  Shortened the broach (even more than its broken state). Am pleased with the fit.
The motor shaft has a thread on the end so will use that to hold the pulley on.


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## RodF (Aug 19, 2014)

Removed the original huge DC motor from the mount, it will need a good clean up.  Due to the tortuous route of the belt the motor is going to end up closer to the spindle so I'm hoping I will still be able to use this mount.


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## RodF (Aug 24, 2014)

Took the spindle off again and fitted the continuous belt.  As you can see it will need an idler pulley to guide it through the back belt aperture.  Looks like there is plenty of length in the belt and also may not need an idler at the motor end.  Have also been working on the electronics for the servo controller.  Not especially difficult but it has been quite time consuming.


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## RodF (Sep 2, 2014)

Progress has slowed due to work commitments, however I have some time off now. Got the servo running today, it seems to have plenty of low speed power and runs very smoothly up to full rpm.  Got one of my friends, an electronics engineer to look over it before I powered it up.  Still a little tuning to be done.


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## RodF (Sep 2, 2014)

Got the motor mount cleaned up and undercoated.  I will make the adapter mount before I paint it so it can all be done at once.  Before I make the adapter though I will need to make an idler pulley for the belt.


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## RodF (Sep 2, 2014)

Cut the drive slot for the tail stock adjustment screw.  This was a bit of a practise run for cutting the slot in the cross feed drive shaft.  So far so good.
Still need to make the adjustment screw retainer.  I have no reference photos of these parts so am just doing what I think will work.


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## RodF (Sep 3, 2014)

Tried cutting a keyway in the 5/9" silver steel. The 2 cutters I had borrowed didn't like it at all.  Went and bought a length of 5/8" bright 1045 bar and ordered a new 3mm HSS slitting saw blade.
Made a start on the idler pulley wheel.  The thin belt means I can use a small diameter pulley.  I've got some 13x6mm flanged bearings lying around that will be perfect and also a 13mm reamer.  The wear on my old lathe means I cannot bore a hole 45mm long without it being tapered, the Cromwell should be way superior.


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## RodF (Sep 3, 2014)

Drilled bored and reamed the idler pulley.  Nice bearing fit.  Now to mount it to the lathe.


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## RodF (Sep 4, 2014)

Made the mount from 10mm ali plate and some .050" titanium I had laying around.  I need to remake the titanium side plates for more belt clearance but the concept is going to work.


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## RodF (Sep 4, 2014)

Made new pulley mounts to give more clearance for each side of the belt. I could get another couple of millimeters out of it but will see how this works out as they say an inch is as good as a mile.  Ground away some of the pulley hole as well.


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## RodF (Sep 5, 2014)

Now I am happy with the belt run I have started on the motor mount.  First job to cut a 70mm hole in the plate.  The pictures say it all.


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## RodF (Sep 5, 2014)

Milled the faces of the motor mount and also a recess for additional belt clearance.  Transfer punched the motor mount holes and centre drilled then drilled them.


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## RodF (Sep 6, 2014)

Fabricated an adapter for the motor mount plate to connect to the tension adjusting plate.  I think there is enough weight in it for sufficient belt tension.


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## RodF (Sep 9, 2014)

Got the final holes done on the mount and cold galved it.  It has been one of those fitting jobs where the parts are on and off quite a few times. Ready for the final fit now.  Before I run up the motor I want to make the linear slider for the speed control.  I need to convert linear motion to rotary motion for the control potentiometer.  This is where the 3D printer will come into play.


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## RandyM (Sep 9, 2014)

This is great stuff Rod. Keep it coming. And you do nice work.


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## samthedog (Sep 9, 2014)

Excellent progress. You have to be happy with the results so far.

Paul.


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## RodF (Sep 10, 2014)

Thanks for the support guys.  I feel like I have the project under control and can finish it to reasonable standard.  Still a lot to do and I expect it will fill another page at least.

Rod


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## RodF (Sep 12, 2014)

Started work on the speed control mechanism.  I am going to make the parts on my 3D printer.  First some tests to get a nice sliding fit linear bearing. These will slide on 2 1/4" stainless steel shafts.


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## RodF (Sep 14, 2014)

Working away at the parts for the speed control mechanism.  Have drawn up most of the parts.  Work in progress.


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## RodF (Sep 14, 2014)

Here is the potentiometer drive wheel


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## RodF (Sep 19, 2014)

I have the linear slider nearly finished.


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## RodF (Sep 24, 2014)

I have been working on the speed control mechanism.  Have been making new parts to fine tune it.  Nearly there now, just need to make the knob.


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## RodF (Sep 24, 2014)

Changed the filament to black and printed a speed control knob.  Added a regulator to the control circuit, this gives me speed control in forward and reverse, servo on, and fault reset.  Now need to print an enclosure for the transformer and circuit board and wire it up properly.


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## RodF (Sep 24, 2014)

Got the control knob installed.  Am happy with the action.


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## RodF (Sep 27, 2014)

Started on the enclosure for the speed control electronics.  Here is a screenshot of the base in Solidworks.


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## RodF (Sep 29, 2014)

Drew up and printed the top of the speed control power supply box.  It supplies variable +-10v to the servo drive.


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## RodF (Oct 3, 2014)

Finished off the servo speed control box.  Started on the front panel electrics.  First up is an RCD for the main power supply.  I will print an enclosure for this and also one for the forward/reverse switch, servo on/off and servo reset.


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## RodF (Oct 8, 2014)

Making more parts on the 3D printer.  A magnet holder on the back of the spindle for the RPM counter and a housing for the forward reverse switch, servo on switch and servo fault reset button.  Have also done the permanent servo mounting so I should be able to run the machine shortly.


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## RodF (Oct 10, 2014)

Got the servo wired up ran up the lathe. It is working as I had hoped. I've attached a little video of it accelerating up and down in forwards and reverse.

View attachment MVI_2711.AVI


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## RodF (Oct 12, 2014)

Got the RPM sensor fitted and made a power supply for it.  The power supply is an old wall wart with a 12v regulator and a connector block on a piece of vero board glued to it.  I ran it up to just over 1000 rpm, I don't think it will do 2000as spec'd but is plenty fast enough.


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## RodF (Oct 18, 2014)

Started the repair to the top slide.  The plan is to screw and silver solder a steel insert to the cast top slide.  I have been quite apprehensive about doing this as it quite a complex shape.  Started by milling the top slide. Am preserving as much of the metal surrounding the clamping screw hole as possible.


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## RodF (Oct 18, 2014)

I made a template for the steel insert and transferred it to some steel stock.  Roughed it out on my fibre disc cut off saw.  Milled it and hand fitted it with a file.


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## RodF (Oct 19, 2014)

Screwed and silver soldered the repair part onto the top slide.  Mounted it on the rotary table and machined the edge, then surfaced the base.  Finally drilled the hole for the clamping bolt and filed down the excess solder on top.


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## JimDawson (Oct 19, 2014)

Nice job.  Great fit up.


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## samthedog (Oct 19, 2014)

Lovely work Rod. I am thoroughly enjoying this thread. Nice work on the cross slide.

Paul.


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## RodF (Oct 19, 2014)

Thanks guys. Next job is to make a Gib for the top slide.


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## RodF (Oct 19, 2014)

Cut a piece of gauge plate for the gib.  Made a fixture to hold the plate while I milled the angle.  It turned out too thick so milled it down in thickness.  Put some blue on to mark the adjustment screw positions and used a bull nose cutter to make the dimples.  I will make some new adjustment screws at some point as one is lost anyway.  You can still see the engine turning on the side of the top slide.


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## RodF (Oct 21, 2014)

The last major part to make is the cross slide drive shaft.  This is a 30" long 5/8" diameter shaft with a slot cut in it for most of its length.  On my mill the slot needed to be cut in 3 operations.V blocks and clamps allowed for repositioning without losing registration.  I need to get the lathe up and running now to machine the shoulder of the shaft to fit into the driver. First I will need to machine the chuck adapter to fit my 4 jaw chuck.  So getting the lathe running will be my main focus now.


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## RodF (Oct 22, 2014)

Worked on getting the lathe assembled today.  No major problems.  The worst thing so far is the amount of wear on the cross slide ACME thread and its nut, not a huge problem as backlash is not a big issue there.  Cut my first chips on it, modifying the chuck adapter plate for the 4 jaw chuck.  The adapter plate is cast iron and somewhat hardened so it is quite hard work.  Managed to get the belt slipping so will need to add weight to the motor so I can get more tension on the belt.  Still plenty to be done.


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## RodF (Nov 10, 2014)

I've been out of town and concentrating on my 40% Slick 360.




Have taken the spindle out of the head again to set the tapered bearings properly.  Will also add weight to the motor mount for more belt tension.


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## RodF (Nov 12, 2014)

Got the 4 jaw chuck fitted to the one chuck backplate I have.  I will probably get a precision 3 jaw chuck and make a new backplate for it.  Spent some time getting the motor aligned properly so the belt runs true and also getting the apron action nice.


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## RodF (Nov 17, 2014)

Machined the end of the cross slide auto feed shaft to fit in the gearbox. Trial fitted it and all is well.


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## RodF (Nov 25, 2014)

Have started making things on the lathe . However still plenty to do.  I need to replace the top slide lead screw and nut.  The screw is well worn and there is lots of play in it.  Have ordered a 3/8" ACME tap for the nut and will make the thread on the lathe.  Have also ordered a set of imperial taper pin reamers to redo all the slider drive handle retaining taper pins.


Worn top slide ACME thread


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## RodF (Nov 29, 2014)

Undercoated the last few parts.   The steady's and the back gear mounting arms.  The travelling steady is a beautiful bronze casting and I will be using it soon to make a new cross slide ACME thread.  Unfortunately ordered a right hand 3/8" ACME tap for the cross slide nut before realising it was a left hand thread.  However will probably use it for a Z axis drive on a CNC router.


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## valleyboy101 (Nov 30, 2014)

Hi Rod,
Your Cromwell is coming along beautifully.  Nice job on the cleanup and paint job.
Michael


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## RodF (Dec 12, 2014)

Thanks Michael, I'm afraid it will slow down now as I am working long hours now for the next 4 months.  However I will keep it ticking over.  Got some tail stock tooling and a knurling tool also a set of imperial taper pin reamers and a left hand 3/8" ACME tap.  Some bronze should arrive soon for the cross slide nut and a steady finger.  Finished off the switch housing.


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## RodF (Feb 16, 2015)

I'm still working long hours and will be away on location filming all around New Zealand, almost a paid holiday really.  In a couple of months I will do the final push on the Cromwell and finish it off.


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## Whittler (Feb 19, 2015)

Hi Rod, I am new to this site, joining after having found your Cromwell rebuild project.  First my congratulations!  You've brought new life into another piece of great British engineering having faced quite a few challenges along the way!  Well done!  
I have just acquired the same lathe and am now assessing what I have and what I have to do!  My lathe came without the stand and motor, so for sure I have to consider what to do about that at some time.  There are a few points I am not clear about so far, particularly about the headstock adjustment / disassembly.  Before I launch right in, I hope you might point me in the right direction? At the moment the Bronze/Brass thrust end caps (the visible castellated C spanner ones at both ends) are not 100% tight. Should they be? I can rotate them just a bit either way by hand, but they cannot be undone by hand. What holds them tight?  I have a cross section drawing from the manual but its not really conclusive on this so any advice would be appreciated.  There appear to be a few differences between our lathes, a bit of product development I think.  The base for my compound slide is a gunmetal casting, and not cast iron for example.  Mine is number 946. Apparently there were only about 350 made, so quite rare as you know.  I hope to hear from you.
Paul


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## RodF (May 7, 2015)

Hi Paul sorry for the belated reply.  How have you got on with your machine? I will be redoing the belt on mine so will reacquaint myself with the head setting then.
Have ordered a new belt from Lathes UK also more taper pins and some U screws to hold the Gearbox plate on.  
First job will be to make set screws for the hand wheels. Once they are done I can get the outstanding chrome work done.


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## Whittler (May 8, 2015)

RodF said:


> Hi Paul sorry for the belated reply.  How have you got on with your machine? I will be redoing the belt on mine so will reacquaint myself with the head setting then.
> Have ordered a new belt from Lathes UK also more taper pins and some U screws to hold the Gearbox plate on.
> First job will be to make set screws for the hand wheels. Once they are done I can get the outstanding chrome work done.



Hi Rod, and thanks for your reply.
The lathe is coming on quite well now. It has presented challenges, the tailstock and gearbox were not original to the bed it seems, so that has taken quite a bit of alignment and fettling.  I have had to make a stand, fabricate an underslung motor with VFD and make several parts that were missing, along with all the small stuff like replacement sight glasses, wicks etc.  The headstock is sorted now with new main bearings.  I had it spinning under power for the first time yesterday, and am really impressed with how smooth it runs, and that was without oil in the headstock!  This one had a conversion to use a link v belt drive, and I've stayed with this, although there is very little clearance under the backgear engagement rod.   I'll make a judgment call on whether or not to go the extra mile with re-chroming - this was only intended as a spare to use while I can work on my other lathe.  There appears to be a small amount of wear in the bed, I would  guess around 0.002" along the length, which makes the saddle a bit stiff near the ends.  I may have to make some compromise with the saddle gibs.  On the whole you can't fail but to be impressed with the build quality, more or less hand made I would say.  The tumbler reverse box is a work of art!
Will try and send a pic later.  By the way - what are U screws?  Cap heads? Socket heads?
Regards
Paul


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## RodF (May 8, 2015)

U screws are rivet like screws to be hammered into unthreaded holes.  They are to  hold the gearbox lever indent plate on.  Had to buy 100 for US$14 with $25 postage.


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## RodF (May 21, 2015)

U screws, belt and taper pins arrived. I now have enough U  screws and taper pins for 10 machines.


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## RodF (May 25, 2015)

Making thumb screws for the hand wheel dials.  I need to brush up on knurling. once these are done I can take a few things to the chrome plater.


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## RodF (May 27, 2015)

Didn't really think the process through so I had to buy a 3/16" BSF tap and make a mandrel to hold the screws for knurling.  The result was a bit fine but I prefered that to the next coarser cut. Original is on the left.


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## RodF (May 27, 2015)

On the cross slide wheel.


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## RodF (Aug 3, 2015)

Decided to use the belt from Lathes.co.uk.  Made a fixture to hold it in position and to clamp the join.


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## RodF (Aug 3, 2015)

Had some chrome work done. Also got the cross feed drive shaft taper pined in.


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## RodF (Aug 12, 2015)

Have been adjusting the motor mount for a good fit, which took a while.  Sorted out the light and RPM display stand.  Need to make a housing for the RPM display on the 3D printer.


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## RodF (Aug 13, 2015)

Made a pin and a retaining socket for the gearbox change arm.  Not sure how close to the original design it is.  Had to get a 3/8" BSF intermediate and bottom tap for the retainer from Tracy tools in the UK (they are great). Now I need to find or make a spring for it, needs to be 6mm or 7/64" diameter.  Got the plate on too finally used those U screws. Really need to clean up the knurling on that knob and get it chromed.


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## RodF (Aug 18, 2015)

Working on the back gears.  I need 2 more 30 tooth gears but nearly everything else is there.  Blanks are made ready for gear cutting also a mandrel.  Just need to make a brass guide for the broach to cut the key way.


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## RodF (Aug 19, 2015)

Cut the gears today.  Just need to broach the key ways. Next up 40 tooth gear.  The only problem is that I need a 45 or 9 hole indexing plate for the 90:1 rotary table to cut the 40 tooth gear.  I am also wanting to cut a 76 tooth gear for another project so I need a 38 hole index as well.  Fortunately I can use the indexing plates I have to make the new plate.


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## RodF (Aug 19, 2015)

Made a new index plate today 38 and 45 hole, there is room for more hole patterns but will leave that till I know what I need. It might need to be 77 or something odd like that.  Now I can move on to the 40 tooth gear for the Cromwell.


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## RodF (Sep 1, 2015)

Made a 40 tooth gear.  I think I have all the gears I need now.


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## RodF (Sep 13, 2015)

Am cutting metal on the lathe now and have been setting up the tail stock.  However am having problems with the spindle jamming.  To release I have to back off this locking threaded collar.


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## RodF (Sep 14, 2015)

OK so I am having trouble adjusting my spindle bearings and end play. How to do it?  I am going to try and answer my own question. Hopefully those viewing this will chime in with their ideas as well.
Here is a cross section of the head, spindle nose to the right.


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## RodF (Sep 14, 2015)

The spindle runs in tapered split plain bearings.


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## RodF (Sep 14, 2015)

As the bearings wear they can be tightened with these threaded adjusters.


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## RodF (Sep 14, 2015)

End loads are carried with these plain thrust bearings. They are also pined to the bearing adjusters.


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## RodF (Sep 14, 2015)

On the back is a threaded lockable collar to adjust the end play.


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## RodF (Sep 14, 2015)

OK this is the adjustment procedure I am proposing.
One bearing at a time.
Back off the inner adjuster to allow the bearing to be tightened.
Screw in the outer adjuster till the spindle just nips up then back off a bit (not sure how much).
Screw in the inner adjuster to lock the bearing in place.
Repeat with the other bearing.
Finally screw in the end play adjuster till the spindle nips up then back off and lock.

I will give this a go later in the week.


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## Whittler (Sep 14, 2015)

RodF said:


> OK this is the adjustment procedure I am proposing.
> One bearing at a time.
> Back off the inner adjuster to allow the bearing to be tightened.
> Screw in the outer adjuster till the spindle just nips up then back off a bit (not sure how much).
> ...




Hi Rod, I had similar problems with mine,  the mainshaft just got tight all of a sudden.  I had more or less adjusted it the way you describe.  You have to make sure the inner and outer locking rings are acting on the taper, and work together on it.  It can be difficult to feel when the locking rings are in contact, they are quite tight to turn anyway.  I found I had to more or less use the inner rings to first push the taper out a bit, and then clamp from the other side.  I was surprised how much I had to back everything off, but now it runs very smoothly and without play.  

What did you use for your wick oilers?  I used 2mm paraffin lamp wicks, but they seem to syphon the oil out of the reservoirs overnight.  I am using a light weight hydraulic oil like Hyspin 32.

I am still in the process of finishing the Cromwell off, but on initial commissioning it appears to be very accurate, and nice to work with.  I don't like the visible cross slide screw, which seems vulnerable to swarf ingress from the top, maybe I'll have to come up with some kind of cover.

Good luck, I am sure it'll come good, just needs tinkering!

Regards,

Paul


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## RodF (Sep 14, 2015)

Hi Paul thanks for the input.
Regarding the top slide.  This Cromwell on Tony's site http://www.lathes.co.uk/cromwell/page5.html has a cover.
Rod


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## Whittler (Sep 14, 2015)

RodF said:


> Hi Paul thanks for the input.
> Regarding the top slide.  This Cromwell on Tony's site http://www.lathes.co.uk/cromwell/page5.html has a cover.
> Rod
> View attachment 110756



Hi, mine is the same as in the pic but wind the cross slide in a bit and the feed screw is exposed. No cover.
Paul


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## RodF (Sep 15, 2015)

Hi Paul, mine has no cover at all.  It is an early model with the short tail stock.  It is number 845 so I assume it is the 45th production model so must have been built in 1946 or 1947.


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## RodF (Sep 19, 2015)

Cutting metal, no jamming yet. This is the guide for the broaching tool to cut the key ways in the gears I made.  A few more hurdles yet.  Like a back plate for the 4 jaw chuck.  A mount for the RPM display.


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## RodF (Sep 27, 2015)

Got the accessory shelf in and moved the lathe to its final position. Front bearing is still a bit loose so still some work there.  Nearly finished drawing up the RPM display mount.


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## RodF (Oct 3, 2015)

Got around to making the broaching guide and cutting the key ways in the gears I made earlier.


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## RodF (Oct 3, 2015)

Made the RPM display holder on the 3D printer. I tried to stay true to the original design. Colours not a bad match either.


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## RodF (Jan 14, 2016)

Still working away at the Cromwell lathe.  Got the gearbox sorted out now.  Next is an adapter for the 4 jaw chuck then the steadies.


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