All lubed up, gibs and leadscrews carefully adjusted for smooth operation and you're ready to go - a well maintained lathe is a joy to use.
How to ensure your mini-lathe is a truly well oiled machine
As with any item of machinery time spent on regular care, maintenance and lubrication will pay dividends.
Not only will your lathe be more pleasurable to operate, it will extend its working life almost indefinitely. The smoother travel of the carriage and slides is also conducive to the improved surface finish of turned parts.
Weekly
After a good clean up to get rid of debris coat the ways with way oil and go round the oiling points with a general purpose oil and that’s it – job done.
Every six to twelve months
The following step by step routine is more of a 6 or 12 monthly service. Though, if like me, you have not given your lathe a thorough going over since you first bought it then it’s time to get stuck in.
Right, so where do we start ?
First, unplug your lathe from the mains power supply.
Slide the tailpost assembly off the bed for a thorough clean especially underneath where there could be a build up of swarf.
For removal of swarf, chips and general debris I use a cheapo paintbrush and a decorators scraper to shovel up the bulk of the waste followed by a good going over with the workshop vacuum cleaner. I start from the top, in other words from the toolpost downwards so that all the debris finishes up in the tray. A blast of air from your compressor will clear out awkward areas. Don’t forget to rotate the lead screw and give it a thorough brushing and a blast with the air gun. I then shovel the debris up with my scraper before bringing in the vacuum cleaner to finish off. A squirt of brake and clutch cleaner followed by a final wipe with a paper towel completes the cleanup.
The next stage is lubrication. Whilst you could use motor oil on the basis that any lubrication is better than none it is far better to invest in a dedicated slideway oil. You will also need some general purpose grease for situations like the concealed slide leadscrews and metal change gears.
You will also need some general purpose oil for all those oiling points. Bogs tells me that it is common practice amongst engineers to use a 32 medium grade hydraulic oil.
Due to its exposure to debris, oil is better than grease on the main carriage leadscrew. White lithium grease is the preferred choice for plastic change gears and may also be used as an alternative to general purpose grease.
Whilst you may already have general oils and greases on hand slideway oil can be a little more difficult to find. Chronos are a good source and they can also supply a decent general purpose oil. Remember all their prices include VAT and free delivery in mainland UK.
5% Discount exclusive to Start Model Engineering regulars from Chronos Engineering Supplies
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Just enter SME1000 when prompted during checkout and you will receive 5% off (don’t pay with Paypal Express as this skips the voucher code option. Standard Paypal or debit/credit cards work fine).
One piece of good news is I have been given to understand that the main spindle in the headstock in 99% of lathes runs in ‘sealed for life’ tapered bearings and does not require any lubrication.
Click on any image for a larger view.
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- Remove the bulk of the swarf by GLOVED hand, swarf and chippings can be razor sharp.
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- A cheap paintbrush is just the job for brushing debris down into the lathe tray.
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- I used an old paint scraper to shovel up the waste.
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- A blast from the air gun cleans out those awkward crevices.
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- A squirt with brake and clutch cleaner nicely cleans up all surfaces.
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- A touch of general purpose grease keeps the metal gear wheels running smoothly. Use lithium grease on plastic wheels.
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- The topslide wound back prior to removal and showing the all important gib.
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- Underside of Topslide prior to final clean and greasing of the leadscrew
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- Topslide removed and gib withdrawn, a good opportunity to give the sliding surface an improved finish.
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- Wind the cross slide away from you to remove. It may be necessary to remove the back guard to gain clearance.
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- Undo the bolts either side of the dial and handwheel to withdraw the leadscrew
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- The leadscrew can now be withdrawn for cleaning and lubrication with general purpose grease.
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- Re-assembly of leadscrew prior to fitting of cross-slide plate.
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- With the cross-slide removed the ways can be cleaned up and lubricated with way oil.
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- The cross-slide leadscrew reay for cleaning and application of fresh grease.
Clean up that chuck
If the chuck on your mini-lathe is starting to feel a bit gritty or notchy it is more than likely its due for a thorough clean and lube. Contrary to my initial concern the whole process was surprisingly easy and straightforward. I was expecting bits and pieces to make a bid for freedom as soon as I released the back cover but no, they just sat there. So with mug of coffee at my elbow here goes.
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- Three jaw chuck on my Chester lathe due for a thorough clean and lube job.
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- Jaws removed and all set to attack the innards to remove months of accumulated debris.
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- With essential morning cuppa on hand the plastic back cover held by 3 screws cover is removed.
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- The bevel gears revealed adorned with a fine layer of brass chippings.
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- The three long perimeter screws are removed which releases each of the three bevel gears.
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- The three bevel gears removed – they are not location specific.
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- The scroll plate is removed next, it may require a light tap with hammer and drift to free.
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- A blast of air effectively removes debris even from awkward crevices.
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- Scroll ring Use general purpose oil on all components on reassembly.
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- After thorough cleaning and oiling of all components the chuck is reassembled in reverse order to disassembly.
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- Top tip – wrap your chuck in a paper towel and give it a quick spin to remove excess oil.
Right, so with the chuck back in the prime of health it’s time for lubrication of the ways, cross slide and top slide as we reassemble.
Let me repeat, there is no need to do a full strip down each and every time. Oil the bed ways and feed lubricant into the oiling points on a regular basis and all will be well.
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- Two or three drops of GP oil in each of the oiling points, use a point to open the ball seal if necessary.
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- Way oil and a general purpose oil available from Chronos with a 5% discount to SME visitors.
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- Brush the way oil on to bare metal bed ways on top and side surfaces.
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- Apply a general purpose grease on cross and top slide leadscrews during reassembly.
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- The top slide swivel is oiled and reinstalled into position.
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- Way oil or a general purpose oil is brushed onto the top slide dovetail.
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- The top slide gib is tweaked up starting with the centre screw then the two outer screws.
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- Run lathe at slow speed and brush a coating of oil onto the lead screw. Don’t use grease as this will attract too much debris.
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- After a good clean up under the tailstock apply wayoil to all contact surfaces including the clamping block
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- Cleaned and lubed the tailpost slides back into position.
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- All lubed up, gibs adjusted – a well maintained lathe is a joy to use.
Adjusting the gibs
You should aim to remove any slack in the carriage, cross and top slides whilst retaining smoothness of movement. Until you develop a feel for adjustment it is a case of trial and error to achieve the desired balance between any excess slack and smooth control. Free off the lock nuts and try adjusting the screws in and out whilst cranking the feed wheel. You will quickly sense when the gib is beginning to bite and you find that sweet spot. I find I get better results if I adjust the inner screws first followed by the outer screws.
Incidentally there will be times when it is desirable for rigidity to ‘lock’ the slides against any possible movement. You may find there are what look like gib screws but without lock nuts. I use these to lock up movement of the slide. Most lathes have a facility for locking the carriage, useful on facing and parting off operations. Check your lathe manual for location of this lockdown screw.
Adjusting the leadscrew nuts
This central hex screw adjusts the cross slide leadscrew nut. You may have an extra screw either side.
For the cross slide there is usually some form of adjustment for taking up any play in back and forth movement (as opposed to sideways movement which is controlled by the gibs).
On the top of the crosslide there are usually three in line adjusting screws.
Loosen all three screws then tighten the middle screw until just snug then tighten the two outer screws until they are also just snug. In the case of my lathe there is just one screw which I slacken to gain free movement. Then, whilst cranking the leadscrew handle, I tweak it up until it just starts to bind, indicating that any slack has now been removed.
Whilst lathes produced in China have improved enormously in quality their handbooks leave much to be desired and provide little or no guidance on adjustment. So, on your lathe, you may need to experiment with various settings until you develop a feel for it.