Lev­el­ling the lathe

The Shed - - Levelling A Lathe -

I set up the lathe by clean­ing the ways with ace­tone and in­spect­ing them. There should be no sig­nif­i­cant div­ots or pro­jec­tions — if there are, it’s a good idea to use a stone on them to get them flat. Ide­ally, it’s best to level some­thing us­ing just three points.

Put a jack un­der the mid­point of the tail­stock end and then just bal­ance the thing from the head­stock end where all the weight is. I didn’t have any­thing small enough to do that as the best jack I have is too big to fit un­der, so I tried us­ing a lift­ing jack that I have, but it tended to lift the end too far to be use­ful. Usu­ally I se­lect three points across the ways to find level — un­der the chuck, in the mid­dle, and against the tail­stock.

I set all the feet at their low­est point so they were all more or less even. Then I be­gan the busi­ness of ad­just­ing one foot at a time un­til I could get the level flat. It is a te­dious busi­ness and very tire­some, es­pe­cially on your own. My thigh mus­cles haven’t quite re­cov­ered. I

It’s not ex­actly pre­ci­sion, but it’s not bad for a small lathe, and overall I’m happy

did even­tu­ally re­sort to us­ing a mir­ror to save the con­stant mov­ing up and down. Even­tu­ally you will get all three points roughly in line and then it’s just a mat­ter of fine-tun­ing. You can rarely get it per­fect. To dou­ble check I also put the level on the car­riage, since this is the op­er­a­tive bit. It’s rec­om­mended to do the lon­gi­tu­di­nal level first. The lon­gi­tu­di­nal level is the least im­por­tant but it gives you a base to start from. The most im­por­tant level is the lat­i­tu­di­nal one across the ways. This is where twist will man­i­fest and that will cause you the most is­sues.

Test­ing

Once you are happy, or when you get to the point that you can’t get it any closer, it’s time to check the ef­fect. Lock all the feet. Put a test bar in the chuck and skim the end off. Bore a cen­tre hole for the live cen­tre. Af­ter mak­ing a quick skim cut, make a cut at each end of the bar, enough that you can mea­sure with a mi­crom­e­ter. Mea­sure both cuts and see how they com­pare. With luck they will be per­fect; in prac­tice they’re likely to be out by a greater or lesser de­gree.

If there is still sig­nif­i­cant vari­a­tion, check that the tail­stock is aligned prop­erly. Check the amount of vari­ance and move the tail­stock by half the dif­fer­ence. If the ta­per starts at the tail­stock end then move the tail­stock away from you; if it’s the other way round then move it to­wards you.

Mine still has a small vari­a­tion of .001mm over 300mm. It’s not ex­actly pre­ci­sion but it’s not bad for a small lathe, and overall I’m happy. Once the lathe is level it pays to check it reg­u­larly, but it’s al­ways eas­ier to level the sec­ond time around.

Level!

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