Flexispeed Mk 2 Restoration - Final Questions (Hopefully!)

The restoration of my recently acquired Flexispeed Mk 2 lathe is progressing well, and now in the reassembly and adjustment stage. I have a few remaining points on which I would appreciate some advice.

I am not very good/knowledgeable with imperial threads so these questions come out of ignorance rather than laziness!

1) The headstock pulley grub screw is missing. But the grub screw in the back gear wheel (or more correctly, the bull wheel) fits the pulley. It measures 0.25" diameter but what thread is it?

2) The gib adjuster screws on the saddle include locking nuts. But the cross slide and top slide only have adjuster screws. I'm thinking it might be a good idea to replace those with longer screws and add locking nuts. What thread size are these? Or is this a bad idea anyway?

3) I have polished the gib strips in the saddle and slides. What's the right thing to do with these - should they be oiled or run dry?

4) Still on the subject of gib adjustment. Obviously these shouldn't be so tight the saddle (or slides) won't move! But just how tight should that adjustment be? I seem to be having trouble adjusting to the point where I believe there is no play without being what I think is tighter than it should be.

Andy

to find the TPI lay against a imperial rule and with a mag glass check tooth count over a known distance and if say 1/4' was used multiple by 4 =TPI. if pulleys are cast odds on they will be Whit.

This question was asked a few years ago in 2019, search the forum for Flexispeed and you will find it.

I can only answer for my Flexispeed 2 lathe that was bought from the Norfolk Lathe and Tool Co in the mid 1970's, as this lathe has been made by a number of manufacturers there may be variation in the threads that were used.

On my machine the thread in the three step pulley is 1/4 x 20 UNC. The grub screw is a dog point 3/8" long.

On my machine the gib threads for the saddle, cross slide and top slide are all the same, they are:

For the adjusting screws (outer two screws) 6 - 32 UNC (nominal OD 0.138". The grub screw is a cone point 5/8" long. 1/4" AF hex lock nut.

For the locking screw (centre screw) 4 - 40 UNC (nominal OD 0.110". This is a cap head screw 3/8" long under the head.

I have always oiled the gibs on my machine. It can be difficult to get a consistent tightness on the gibs on the Flexispeed, they were not an absolutely precision lathe. The assembly instructions did give advice on easing any tight spots by carefully using a smooth cut file on the gib side of the dovetail. But I would only do that if you are confident you know what you are doing and then only as a last resort. I still have a tight spot on my Flexispeed so obviously I did not attempt it, too long ago to remember now.

I hope that this helps with your machine, there can be variations, particularly on a second hand machine where you do not know its history. Someone might have modified things to suit their own equipment. Just go carefully.

Neil

I bought a spare saddle for my Flexispeed. It was clearly from a different era, manufacturer or had been modified as the gib screw threads were different on each.

James.

Thanks for the reply Neil. I've found that old thread (excuse the pun!) https://www.model-engineer.co.uk/forums/postings.asp?th=144241