New lathe “running in “

[martin107Participant @martin107]

I have ordered a new WM 250 do they need "running in " to get the best out of them or can you just start playing with them and can any one please tell me what tool size you need for them so I can get a couple in ready.

Cheers

Martin

[martin107Participant @martin107]

[Chris Evans 6Participant @chrisevans6]

All things mechanical require a bit of easy running to start with, just avoid running in the higher speed ranges for a few hours and all will be well. Modern oils are good but do not allow things to bed in as quick as they used to, when I rebuild bike engines I use cheap mineral oil for the initial running rather than synthetic which can allow the bores to glaze. So use the lathe but don't "Granny it"

[HopperParticipant @hopper]

Roller headstock bearings. Go for it.

[JasonBModerator @jasonb]

First off I would set the backlash in the gear train from spindle to lead screw so you start off with a quiet running machine. Then give it 5mins running in low speed range at 500rpm, then 5mins at 750 and finally 5 mins at full low ratio then swap to high ratio and just 5 mins at mid speed of about 1500rpm. Have the lead screw turning while doing this.

Check for any excess build up of heat around the head bearings as you do this and for any play in the head bearings afterwards.

[FMESParticipant @fmes]

I agree with Jason, Our Harrison M300s recommend making a low feed rate selection and then:

3 hours @ 540Rev/min

2 hours @ 800 Rev/min

1 hour @ 1200 Rev/ min

1/2 hour @ 1700 Rev/min

so you can make a good judgement for your particular machine

Regards

Lofty

[martin107Participant @martin107]

Thanks Jason,

Can I be a thick newbie and ask how to take the backlash out of the gear train please.

Thanks

Martin

[Mick B1Participant @mickb1]

Without doing it as formally as Jason suggests, what he recommends is pretty much what I did when I first started my WM250V.

It was as much a matter of familiarising myself with the controls, with the sounds and feel of the lathe running. I fiddled with the headstock gear train too, to see how it was put together and how to get the backlash right.

After a few months' use, I took up the headstock bearings a little, and haven't touched them since.

Thing to avoid is engaging power feed when the slide can't move – the shearpins seem stronger than is ideal. About a month after installing the 250, I engaged the longitudinal feed when I meant crossfeed, against a hard-locked saddle. The shearpin held, everything got locked solid and the saddle drive pinion shaft got bent – the one that engages with the bed rack. Eventually I freed it off, and lived with the tight spot caused by the bent pinion for a year before I discovered how to straighten it with the tail of an ordinary crowbar… No more trouble with that since. Nearly 3 years now, and in use most days – I wouldn't go back to the Myford I used to have.

 

Edited By Mick B1 on 23/02/2018 09:11:36

[JourneymanParticipant @journeyman]

Posted by martin107 on 23/02/2018 08:40:38:

Can I be a thick newbie and ask how to take the backlash out of the gear train please.

Thanks, Martin

The change wheels can be set to a good running clearance with minimum backlash by using a sheet of paper. The technique is explained in the rather poor manual (at least on my ancient model it is).

Loosen off the banjo and the various square headed spindles that hold the gears. Working up from the gear on the end of the lead screw trap a sheet of paper between the two gears and press them hard together so that the paper concertinas into the gear tooth shape. While still pressing together tigten up the square spindle nut.

Work up the gear train doing the same for each pair until you get to the spindle gear press this in and tighten the banjo. Be aware that the banjo can move laterally on it's mount, you need to set it's position so that the gears don't rub on the sides. Also be aware that if you take the gears off the various collars and the 'C-clip' retainers are slightly different thicknesses to maintain the side to side spacing of the gears.

I found it useful to make up thin plastic washers to go between gear pairs to stop them moving/rocking side to side which stops the gears rubbing. Use plenty of grease to lubricate and help deaden the noise.

Sounds complicated but isn't really you will soon get the hang of it when you have changed the setup a few times.

John

Edit: typo + photo

Edited By Journeyman on 23/02/2018 10:43:21

[SillyOldDufferModerator @sillyoldduffer]

Posted by martin107 on 23/02/2018 08:40:38:

Thanks Jason,

Can I be a thick newbie and ask how to take the backlash out of the gear train please.

Thanks

Martin

There are no stupid questions! I was puzzled by 'backlash' as well. I'll stick my head over the parapet and suggest Jason means you should adjust the mesh between the change gears for quiet running. Because change gears can be changed, you have a choice about how close together the meshing teeth are positioned. They shouldn't be rammed hard together, nor should they be a sloppy fit.

When assembling change gears I trap a strip of thickish A4 printer paper (or a doubled over strip of thin paper) between the gears as they are meshed together. The paper serves to set the gap. Then, rotate the chuck by hand and remove the paper; at the same time check that the gear train turns smoothly throughout. There shouldn't be any tight spots, nor should there be much taking up of slack when you reverse chuck direction. When all seems good, replace the gear guard and run the motor. Don't be surprised if it takes practice to get the meshing 'just so', and don't worry too much if it's a bit slack. Much better to be too loose than too tight.

Hope that;'s right!

Dave

 

Edited By SillyOldDuffer on 23/02/2018 10:47:41

[JasonBModerator @jasonb]

Do as John has described, can't add more to that.

[MuzzerParticipant @muzzer]

The idea is simply to ensure there is no actual preload between the teeth – ideally there would be zero gap between them but unless you can demonstrate that there is some finite gap, there would be no way of knowing for certain. So different thicknesses will be recommended for various reasons. Some people recommend cigarette paper.

When measuring gears, you mesh them against a "master" (hardened super precision reference) gear with a spring preload (ensures zero gap) and then measure how much radial movement results when you turn them. Ideally there would be no movement if they are perfectly made involute gears. If you deliberately introduced a gap you'd screw up the operation but for a gear train on a lathe it's hardly going to matter.

Murray

There was a guy selling a load of DP master gears on the homeworkshop site recently but I doubt many people would be aware what they were for.

Edited By Muzzer on 23/02/2018 14:19:14

[mechman48Participant @mechman48]

Concur with all the previous 'backlash adjustment' methods. This is how i did mine, a piece of A4 notepad sheet folded over gives between .004" – .006" clearance, I did this with all the gear meshes individually & tightened up as I worked way back to the driver…

​Certainly reduces gear mesh noise noticeably…

George.

p.s. By the way the gunk on the gears is Motor bike chain spray, thicker than oil & doesn't fly off when gears rotate, helps with deadening the noise too.

Edited By mechman48 on 23/02/2018 15:36:28

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