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Project Schaublin 135

The posts are displaying well in the new format, and I must say you take nice pictures! The spindle bearings are lubed with circulating oil from the tank. Take care to clean out the oil lines and the mesh screen in the reservoir. Good luck!
Ole
 
Thank you Ole, yes the tank is super clean as is the filter, all the oil feeds are being replaced with hard wall nylon and push fit unions so there wont be any issues with dirt in them.

VARIATOR # 8

Have now cut the oil/grease seal pockets for the new Viton oil seals, these are 52 x 40 x 7mm and are twin wiper and multidirectional seals so hopefully they will serve the task in hand and keep the thin grease lubricant in the sliding centre section of the Variator assembly so the belts stay oil/grease free moving forward.

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We are now in the process of working out a way to hold the Variator yoke assembly to the mill table to allow the machining of the two pockets to accept the twin bearings.

The end which is deepest inside the base cabinet of the lathe will have two bearings pressed into place so they don't move or fall out as these will have the new shaft inserted from one end and a washer and bolt will fix the shaft in place with some light thrust pressure on the inner race, the end closest to the cabinet opening/door access will have the same bearing configuration fitted but these will be a drop in fit so they will slide out easily, this should allow us to insert the new shaft, and then fit these bearings over the shaft end which will be turned down to suit and fix them again in place with a bolt and washer on the end of the shaft.

Setting up in progress..

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BEARING & SPINDLE RE-ASSEMBLY

While I wait to find time to get over to my mates for his lathe & mill to carry on with the Variator mods I wanted to cover up the bearing race on the back of the spindle, don't really want this exposed to grit and dust too long. Cleaned it off carefully with a dry lint free rag and gave it several puffs of compressed air, followed this with a light coating of the oil I'm using for the gearbox (Mobil Velocite No6).

The bearing cover was also cleaned and the bearing surface coated in some oil, I also added a thin bead of silicon sealer/gasket in the corner of the flange so that when bolted home there was an oil seal between it and the lathe mating face.

There is an art to getting this big bearing flange on, naturally the fit is tight and the bearings are 'sloppy' in their support ring to start with so I placed the flange carefully into its rough place, a light tap of a rubber mallet should give just enough purchase for the flange to be self supporting as it just engages with the rebate in the lathe mating surface but not yet on the bearing. I found that M8 x 45mm bolts will screw in from this point and 'pull' the flange on. You must rotate the chuck/spindle all the time as you literally quarter turn each bolt in a circular pattern.

You will feel when the first bearing race meets the flange bearing seat, but as long as you gently turn the chuck & spindle while nipping up the bolts the bearing will go in and the process gets less stressful, there is a point when the second row of bearings hits the bearing seat but the same process will sort this out too. Once the M8 x 45's have done their work you can replace with the actual bolts and finish off the tightening process - spin that spindle the whole time, if it gets snaggy back off a few turns on the bolts and ensure they are nipping up the flange evenly....

Flange on

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Next the oil thrower (the correct way round! Yup got that wrong first attempt) followed by the locking ring which has those tiny bolts which lock up the ring and were so tight to remove. Still debating if to loctite them in with some medium goo but not sure yet so they are nipped up with an Allen wrench at the moment

The final cover/flange goes over this lot and I was debating if there was any particular way this should be fitted

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Well yes there is, on the inside around the rim you will find a small machined slot and drilled hole, this I can confidently say needs to be at 6o/c so that any oil thrown out into this rim will run to the bottom and drip out via this machined slot and into the oil recovery system. Here is the slot pictured at the bottom..

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Ensure a new 'O' ring is also fitted. This gets bolted to the flange already fitted resulting in this..

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I test fitted loosely the oil catcher along with its rear tray (which varied in design from machine to machine) and luckily it did not fowl on the new oil line push fit union I screwed into the gearbox drain - phew!

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Yes I have sliced off part of that washer, hoping it's the first of only two 'slight' modifications needed to get the new oil feed round to the feed gearbox just behind it, will post the second when I do it! The rest of the lines are all more easy too route.

More later....
 
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Wise words indeed, will look into that suggestion about the 'green' Loctite.

I may also order two new bolts as I'm sure the hex drive heads have been slightly damaged/deformed as a result of removing them, also will grind off the end of the hex driver to ensure a crisp new end with flat faces to give the best chance of fixture and ultimately removal at some stage down the line.
 
Should be good enough. If only barely.

Disclosure:

I don't LIKE "hex" atall. Too easily damaged to the point of useless.

First choice Bristol, second choice Torx II/Torx plus, rather.

A Schaublin is "worth" Bristol fasteners, yah?


:)
Hi had a quick look at the Bristol site, nice concept however looks like finding a big range of metric bolts will be a challenge as it seems its imperial only sadly. These tiny bolts (M5x10) are part threaded with a shank area near the head and the head is CS which means these little items are not an 'off the shelf' item as far as I can tell.

If anyone knows of a source great, and for me a Torx would be a nice alternative as think they have a large metric range of fixings.
 
I was about to place an order for some M5x10 CS Torx bolts when I thought I had better check what this bolt actually looks like and as you can see from below its not going to be a matter of grabbing an M10 bolt and machining the threads off the top of the shank.....

As hopefully you can see from the picture the head is not a CS but a very thin (0.9mm) flat head and I'm pretty sure that if you took a normal Torx bolt in M5x10 and machined the head down to 0.9mm and to the right diameter you would have very little of the Torx recess left to engage a driver with sadly.

Unless anyone can suggest other options I think you are left with replacing them from Schaublin for new ones to give you a chance of having a new hex recess to give a decent driver engagement....

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VARIATOR # 9

The process to machine the yoke for bearings has started, there will be two SKF 7mm thick deep groove sealed bearings in each end with an internal diameter of 20mm. The new shaft will be 25mm between yoke legs and then turned down to the right OD for the bearings.

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In post 143 I mentioned that the washer 'mod' was the first of two to allow the oil line to work as push fit rather than the touch and go copper washer and banjo system, well this is the second 'mod'.......

The push fit fittings stand away from the surface a little more than the original system so in order to get the stiff 10mm OD pipe to connect to the fittings I had a small issue with part of the lathe base unit casting getting in the way. I bought a hole drill with carbide tips as the castings is hard, drilled through and then filed the edges flat and rounded them too. The pipe can now connect up to the two push fittings and provided the drive belt does not foul on the pipe when assembled I will run with this set up in the hope its oil leak free.

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This turned up today, a chunk of bronze rod with a hole already down the middle which I plan to machine the electromagnetic armature bushes from rather than use nylon/delrin.

I spoke to a guy who used to work for Warner UK who remembered that originally these brake units were made with bronze bushes but as the fad for plastics become more popular and naturally cheaper to make they changed the spec, he said bronze is always going to be better and will give a far superior life expectancy and if reamed to the right diameter won't be at all noisy, intact it should be quieter.

This bar is just right dimension wise and the hole already down the middle will need opening out but it will save a lot of machining to get to the right result.....

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VARIATOR # 10

My machining guru has been busy, the ends of the yoke assembly have had the ends milled out to accept the twin bearing sets, part of this design requires a cap to ensure the bearing assembly remains in place, the end which is furthest inside the machine cabinet and as those who know is the end the shaft originally has to be removed from (a real PITA) will now simply be the end stop for the shaft assembly which will insert from the front of the yoke and access should be simple through the large cabinet access door.

This bearing set is a press fit as it wont need to come out but there is a need for a retainer plate and this is the item being machined, pictures of the retaining ring being machined, fitted to the end of the yoke and with bearings pressed in place...

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Next the new 25mm shaft starts the process of machining to fit the new design, due to the concerns over the 'meat' on the ends of the Variator yoke not being suitable for a 25mm ID bearing we opted to machine down the shaft at the bearing sections to 20mm, the feeling is this is still plenty of material to support the Variator pulley system especially as the shaft ID reduction to 20mm is only at the very ends.

Logistically this causes a few headaches when it comes to installation as it's fine on the end you see above as the shaft simply slides into the bearings, but at the end where the shaft is fed from you cannot feed a 25mm shaft through a 20mm bearing! The plan here is to make the pocket milled in the yoke arm a 'drop in' fit so the bearings can be removed easily before the shaft is inserted and then slid over the end of the shaft (which is machined down to 20mm) and the whole assembly secured in place. This securing process is a work in progress but we have a few concepts and ideas so the planned solution will be simple, effective and easy to assemble and dis-assemble.

The end of the shaft that slots in the bearings above will have a circlip fitted which will add lateral stability and add engagement with the inner bearing race.

Shaft machining, the shaft runout was 0.01mm over its length which is very acceptable IMO ...

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Found a few jobs to do on a Sunday when I suspect like many of you you are weary from a busy day on Saturday doing whatever you do so it had to be a 'no brainer' ......

Did some more cleaning internally around where the motor and oil tank go, really grimy in here as you would imagine after copious amounts of oil and rubber from shredded belts have taken their toll, petrol soaked rags and liquid hand cleaner are working well, not planning to get it spotless just clean enough so you don't end up with black marks all up your arms everytime you venture inside the base unit..

While the motor was on the bench awaiting the new brake bushes to be made from bronze I decided to check the bearings, clean off old grease (only manually cleaned them with no compressed air) and re-applied a smearing of new HT bearing grease. At the pulley end there is a cover plate with a fibre seal pressed into it and held by pin punched dots around its circumference, there is quite a gap between the motor shaft and the fibre as over time this has worn. Now whilst this is not a critical part and the chances of nasties getting in is remote but I am going to replace this seal with a modern Viton shaft seal, so ordered a 40 x 55 x 7 seal which should fit nice and the only mod is machining the depth of the pocket 1mm deeper as the current seal is 6mm deep.

Closer inspection shows a rather zealous pin punch operator who was obviously distracted at the critical moment with a cuppa tea and a biscuit as he/she missed the casting and punched the seal :-)

There was a hole under the transfer gearbox for the leadscrew which had a threaded hole going through to the above where the motor sits, I looked at the drawings and could see nothing to indicate why or what should go there in the threaded hole so as the thread was not the same as my recently bought push fit unions, I drilled the hole out and re-threaded so one of the 12mm OD 90 degree fittings could be screwed in from the underside and I will connect up a length of 12mm poly pipe and route down the inside of the base casting and into a drain container under the lathe, don't suppose much will come out but not happy with just letting the discharge empty on or near the motor and belt. If someone can explain what this is and if the threaded hole should be connected up to something I would be pleased to understand the original set up.

Working on CAD drawings for the design of a component for the Variator which will allow the pulley assembly to engage with the new shaft but also allow a small amount of sideways movement so the pulleys will align with belts under running up. More on this 'part' at another time...

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Have made some progress on a few items relating to the 135, the new Variator shaft has spent some time being ground so its nice and straight and round.....

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Have machined up some leg pins to fit into the fine threaded feet adjusters so that the new feet pads will provide support and allow some adjustment with floor levels etc.....

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Machined out the old seal pocket on the motor front bearing cover to accept the new Viton seal...

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Fitted the seal ...

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Have also now machined up the three new brass brake assembly armature bushes, these were made as a direct suggestion by a member of the Warner company who said these brakes were originally made with brass bushes but as plastic became more popular and cheaper they moved over to plastic, brass he said would always be better - lets see, fingers crossed ...

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The new design where the Variator is mounted on a shaft that spins in bearings rather than the Variator spinning around a fixed shaft requires a coupling design that allows the Variator to not only spin the shaft but also allows a small amount of lateral movement along the shaft so the belts self-centre once the machine is up and running following the re-design.

A locking device or set screw would not allow the lateral movement so we have designed what we call a 'split drive dog'.

On the end of the bronze Variator sleeve is a flange which allows the end disc of one pulley to be fixed to the shaft by four bolts, this is the end of the Variator which is deepest inside the cabinet ... (picture taken before cleaning etc)

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The plan was the remove around 9mm from this brass flange in depth and remaking a part 9mm deep which bolted on the end so maintaining the original depth, this split drive dog would use the bolt holes to fix the pulley to the brass Variator sleeve but also using a flat machined into the end of the shaft would engage and turn the shaft as the pulley spun, the machined flat would be wider than 9mm allowing some lateral movement along the shaft whilst still maintaining full rotational engagement.

The crude sketch ...

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The sketch developed into a CAD drawing and to maintain rotational balance we decided to make a extra part that slid into the open slot and that would be permanently bolted in place so the whole split ring dog would not spin out of balance.

Machining and end result ...

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I don't recall seeing lip seals on motors with greased bearings. Lip seals are usually found in oiled environments. The lip depends on a film of oil that gets replenished. I'd be concerned that the film will go away and not be reliably replenished in a grease environment. The prior fiber seal would hold oil as a wick. That said, it probably does not matter if the lip seal stops sealing perfectly in this application.
 
Clever enough. Nicely executed. But I am puzzled.

I have three "slightly" different variators here. One Reeves, one Reeves-like that IIRC is a licensed clone, and the Cazeneuve-patented hydraulically-operated one on the HBX-360-BC. I had repaired "many" smaller size (2 HP or less) Reeves drives on sheet-offset printing presses, forever-ago as well, so not a lot of "mystery" to them, nor where and how they degrade, innards on-out ... to my way of thinking.

Every one of those (but perhaps not those on a Sheldon..) expects ONE of the "cones" to be in a fixed position, axially. Against which... the drive belt finds a proper tracking position as the movable cone is actuated or "follows" under spring - or hydraulic - influence. There is not only no need of allowance for the belt to seek any other course, it is detrimental if/as/when it were to be allowed to "float" to do so.

Example:

On one, (the Quartet combo mill), operation was sore noisy as prior owner had recorded in a You Tube video. The control yoke - which had been cracked, then crudely repaired - was THOUGHT to be the cause, but was the VICTIM, rather.

The ACTUAL cause was tracked down to a roller-thrust bearing having failed, the designer having selected the wrong type... of two options.

Failure had allowed about fifty thou of departure from the intended position of the fixed cone - which was deleterious to belt life (frayed edge) as well as noisy. New thrust bearing adjsuted to poer alignment is what was REALLY called-for - control yoke imperfections not the critical item.

So - given Schaublin's OEM designs are generally well-regarded and durable as-had, and "pioneers get arrows in their a**"
I have to ask:

- Have you just "fixed" the wrong problem?

- Potentially exchanged one problem for a different one?

Or...... made a genuine and enduring improvement?

If so, how so?
So interesting comments and great to get this sort of feedback and questioning.

I get the logic behind the fixed position for one of the cones, it makes sense and to be fair its one aspect of this modification that I have held off machining as I am not fully convinced of the need for a small amount of lateral movement.

I have studied the drawings for the later 'Schaublin' bearing shaft version and cannot see anywhere a fixing method to hold the Variator slide to the shaft, it shows distances from the inside of the yoke boss to the edge of the Variator etc which I assume is the desired running/design position. I would be interested to hear from anyone about this as I can easily just cut the slot in the shaft to exactly match the split ring dog so the Variator assembly is 'fixed' to a position but pointers would be appreciated.

I have attached the drawing of the later version I referred to above so if I have missed a fixing device than please let me know. I will also reach out to someone who knows these machines and ask the same question, thank you for questioning my design direction and hopefully the end result will be the right one.

So maybe I am fixing the wrong problem which is important to consider and is a reply to the first part.

Changing one problem to another also is a possibility, my re-designed shaft is smaller in diameter to the revised version Schaublin made mainly as I did not have the 'meat' on the end of the yoke arms to accommodate larger bearings so this may be an issue, I am hoping that it is not, the bearings may not cope with he forces or rotational speeds however I have chosen a good brand (SKF) and doubled up at each end so there are 4 bearing races. The tension on the belts is not super tight as the design always needed to be a compromise between tension and managing seals and oil leaks. As with many designs there is always a risk and we know failure will simply occur at the next weakest point if you strengthen a part which fails on an original design.

Schaublin design does generally get good reviews but I have to question how good the Variator design was on these earlier machines when almost every one fails when the oil starts to leak out and trash the belts. My goal was to emulate the later design within the confines of using the same yoke etc as €5000-6000 for a new later version is not an option for me.

I would like to think I end up with a reliable fix, its not my idea just copied from Schaublin is its general format so whilst I hope for a genuine improvement the inspiration is still rooted from the manufacturers later design outcomes.

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The original shaft for the Variator has now been modified with the flange end being turned down by 10mm to allow for the new split ring dog to be fitted - the resulting overall size (length and flange dimensions) remains as designed ...

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This shows the sleeve assembled on the new shaft, this was done to check fit and to plan for the next stage, some of which was discussed in the post above which considers if the sleeve needs to be locked onto the shaft in the factory suggested position given the measurements on the Variator drawing or allowed to float laterally slightly to allow for belt alignment etc. The census is it needs to be fixed in one location but still awaiting some guidance from another expert on the 135's ...

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Finally the end with the new split ring dog bolted in place to show the design of the system that will engage the sleeve to the shaft. If we machine a 10.2mm wide slot in the shaft this will effectively give a fixed solution to the system, if the slot is say 30mm wide this will give a 10mm lateral float in each direction from centre.

The whole unit will be put back in the lathe before its fitted out and the face machined flat and to remove the small scratch caused when the de-burring tool slipped! ...

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So interesting response to my question to an authority on these lathes around the floating option on the Variator and shaft, here are some key take aways from the reply email to me:

... the variator is able to swim on the lengh of the complete 25mm bar, from arm frontside to arm backside
... the variator runs on the bar absolute free with axial play of surely 40mm*
... because if you change the speed you see the variator-unit walking a little bit on the bar
... sometimes you see the variator axial a little bit walking without changing the speed only in running


This is naturally the setup on the later Variator system where the shaft (25mm in this case) runs in bearings and the Variator system slides (as it looks) freely along it, this confirms that the 'swim' and 'walking' terms do indicate that allowing the Variator to laterally move does seem to be the intended outcome of the new design so I think for now my gut feeling is cut the slot to allow this to happen and position it so it stops the Variator 2mm from the inside of the yoke arms, a quick calculation shows this will allow +/- 12mm movement from the centre position.

* I believe this refers to the overall gap in mm on the revised yoke and spindle system, looking at the drawings it adds up to 39mm, the older system as in mine has 29mm overall gap.
 
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So the 40mm long slot has now been machined on the main shaft to engage with the split ring dog that bolts to the main Variator assembly, only seen the pictures myself not the item in the flesh but overall the outcome seems good and hoping the resulting system works as designed.

Here are a few pictures of the process ...

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Another small but key job ...
The motor mounting plate which pivots and slides for and aft for alignment and is set using a set screw was all jammed up and needed some TLC and oil to get it freed up and able to slide and pivot, not a challenging job but good to be done. When I took the mount off the motor only two bolts were fitted, I can only assume than in the process of trying to adjust the motor tension when the belts got oiled up that some wally decided it was too hard to reach the two bolts and just left them off! Yes it's hard to reach them when the motor is installed but not impossible so I decided to order new bolts and changed out the remaining two for four new ones and nuts too, both with flanges, the bolt ones serrated.

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Next little job is one I'm doing just 'because', the motor is wired to cable running in a metal flexible sleeve which runs through the cabinet and into the end electronic panel, the cables enter the motor via a metal connector box and have to be fed through a tight 90 degree bend to get them into position for connecting to the terminals, its not a big deal but a faff so I am going to experiment and have ordered a MIL spec 12 pin connector assembly and plan to hard wire one end to the connector box and hopefully the plan will be the feed end will simply be a push fit and lock the connect together. It may be a waste of money etc and time but as I'm re-terminating the wires anyway seems its an opportunistic time to embark on a pointless upgrade :) ... will post the outcome shortly.
 
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