Jolyon, it may help others giving you information if you indicate what part of the world you live in. Ian S C

Try clicking onto the Myford link on the right hand sioze of this page, that will take you direct to Myford. Why do you think a Colchester Student is too big? You can always do small work on a large lathe but the reverse is not the case. As Ian says above…..where are you located? There may be somebody local who can help.

Hi joylon,

The ML7 manual say

640 Rpm ( 1"7/8 pulley & 1450 Rpm motor)

870 Rpm (2"1/2 pulley & 1450 Rpm motor)

1070 Rpm (2"1/2 pulley & 1750 Rpm motor/ 60hz)

This higher value is the max safe Rpm, old babbit bearing manual say

100 meter/minute (330ft) linear speed is max , with heat contol (hand touch)

The probleme is less modern lubricant than heat evacuation.

Certainly too much modication for the benefit

brgds

pierre

Hi JDF ,

Myford sold an upgrade kit for ML7 consisting of new hardened spindle and bronze bearings . Properly fitted and adjusted the new spindle and bearings were good for 2000 rpm running for extended periods and probably ok for much higher speeds .

It is sometimes the case that out of balance problems limit the speed that can actually be used .

Just a mention of something that can occur if running ML7 faster than original design speed :

Heat build up causes spindle to expand longwise and jam up the thrust bearings . No problem if you know in advance – just ease them off a bit .

Regards ,

Michael Williams

Q: Not sure if you need special nickel chrome steel though.

You do and it has to have an Aluminium content as well .

Really and truly with a spindle that is already probably undersized and made of unknown steel I would personally stay away from hardening .

Unless you want to make or buy an all new hardened spindle I suggest that you polish up the journals on the existing one and run spindle in DIY Glacier bronze bearings . Would be worth  making the bearings a couple of atoms undersize and scraping them in and also worth scraping proper oilways .

If your regular use of the lathe is just making the 10 mm bits and pieces that you mention then the bearing loads are almost nothing and Glacier bronze bearings running on old shaft will last forever given plenty of oil .

Michael Williams .

Edited By MICHAEL WILLIAMS on 15/10/2012 18:42:35

the Myford Super 7 was primarily designed to give a much higher top speed than the old ML7.

if you run your old ML7 at much higher than the stated top speed (which will require some steppng up on the drive anyway or a faster motor) then please be very careful!

what a lovely gift!

leadscrew handwheels are easy to obtain… i saw quite a few on sale at very reasonable prices at last year's midlands exhibition. you will definitely need the oilers for your top speeds! they arent difficult to make but can easily be bought too. i would stick to the myford oil specification carefully, and before you run your ML7 at top speed make sure the bearings have been cleaned etc, and not too tight and keep a regular check on the temperature with the palm of your hand as loco drivers do on loco bearings! if you are drilling with very small drills eg for injectors then an added sliding drilling spindle to the tailstock can be recommended to increase the speed.

cheers,

julian

Alec Tiranti is a good supplier.

MichaelG.

You need engineering grades of whitemetal for bearings . Read through these earlier postings :

**LINK**

Regards ,

Michael Williams .

Now tell me what it is and why it is suitable . In fact why not tell us all how to design a plain bearing and choose appropriate materials from the bottom up . Don't omit all the lubrication considerations .