ML7R Lathe

This topic has 6 replies, 5 voices, and was last updated 30 November 2015 at 20:11 by Neil Wyatt.

Viewing 7 posts - 1 through 7 (of 7 total)

Author

Posts
30 November 2015 at 14:42 #214648
Alan Girvan
Participant
@alangirvan88520
Hi,

Please would anyone be able to help with the below queries.

I have got a severe oil leak at the lead screw end of the gearbox. Seems to be coming out of the Lay shaft (No 159 in the users hand book) and (Shaft 140 in users handbook). It mentions in the handbook a laminated washer but when i take this out it seems like a wee shim washer that has been made out of a coke can or something similar. Could this be the problem?

Also when using the lathe to cut bar it always cuts narrower at the end than it does at the chuck, when i adjust everything up it will cut straight but after it is used for an hour or two it goes back to cutting small at the end again. Something seems to give but don't know what. Is it possible that the head of the lathe could be moving as this only seems to happen when i a taking a fairly heavy cut.

Many thanks for any info you may be able give.

Alan
Advert

30 November 2015 at 14:42 #24252
Alan Girvan
Participant
@alangirvan88520
30 November 2015 at 16:00 #214653
Brian Wood
Participant
@brianwood45127
Hello Alan,

The oil leak is easy, the box is overfilled with oil and it is escaping from where it can. There are no oil seals on the shafts you mention. Unscrew the level plug [#134 in your handbook] and run the surplus out until it just drips, then refit the plug. The O ring oil seal for the plug should be OK, it is just held in compression.

The turning problem needs some more information.

1 Get hold of the headstock and try to twist it across the bed in both directions. It should feel as solid as a rock. That being so, the head alignment is very likely to be as it should.

2 Are you turning with tailstock support? If so, is the tailstock offset for taper turning?

3 How long is the work? What diameter? Is the chuck grip good? Is the tool above or below the centre height?

With some answers to those questions we can go further

Regards

Brian
30 November 2015 at 16:13 #214655
Lambton
Participant
@lambton
Alan,

Oil is probably coming out as described if the gear box is over filled with oil. I suggest that you put a suitable receptacle under the gear box, remove the level plug (No 134) and leave it for a few hours until all surplus oil has drained out. Put the plug back and carry on. It is best to use K68 grade hydraulic oil as this is a bit sticky and tends to stay put (see the note on lubrication on the inside front cover of the later editions of the instruction manual No 712V).

The laminated washer (154) is to control the end float of the shaft and is not there to form a seal of any kind. It is made of laminations on shim and when the box was fist assembled in the factory a fitter would remove some of the laminations in order to get the end float within limits. It may well look like a bit of drinks can but it is rather more technical than that! Best not to interfere with it.

From your description I think you mean the lathe is not producing a parallel job when taking a long cut off the diameter. There can be lots of reasons for this with the most likely cause being the way the tooling and the job is set up. I do not recommend that you do anything drastic with the head stock casting alignment until you have tried all the standard techniques for good turning practice. Check the adjustment of the saddle, cross slide and top slide gib strips and the make sure the lathe bed is secure to the stand/raising blocks. Check for "levelling" as described in the lathe handbook (page 12 in my Super 7 book).
30 November 2015 at 16:39 #214660
David Clark 13
Participant
@davidclark13
Check the main bearing adjustment and the roller bearing positions.

Also make sure the felt oiler is letting oil pass, they have been known to dry out,

If the front bearing is loose the leverage away from the headstock may be a lot more than close to the headstock or the tool is pulling the work in. It is not difficult to adjust the bearings but you do need to follow the instructions in the manual. Then turn a test bar in the chuck to check the lathe is turning parallel. If not true use a spirit level (cheap one will do) release all four bolts slightly and level in the cross axis. Nip the two bolts lightly at the headstock end. Set the lathe level along the bed By adjusting the back foot adjuster and nip it down lightly. Then tighten up the front adjusting screw so that it just touches the bottom of the lathe bed and nip it.

The bed should be level enough as a starting point for further tests.

I did an article on adjusting level on an ML7R which is probably in the archive section. This also covers tailstock alignment.

It is the practical engineer part 2 In workshop processes.

Edited By David Clark 1 on 30/11/2015 16:43:39
30 November 2015 at 19:22 #214696
Alan Girvan
Participant
@alangirvan88520
thanks everyone for your input i have tried all these tests the bar i am cutting 25mm with 50 overhang down to 18mm with no tail stock support
30 November 2015 at 20:11 #214700
Neil Wyatt
Moderator
@neilwyatt
Here we go, David's article inb setting up a Myford:

http://www.model-engineer.co.uk/news/article/the-practical-engineer–part-2/4784

Neil
Author

Posts