Advice on an Internal Acme Thread

I've been getting my info on lathes.co.uk

Repair Parts
Although Sanford-produced parts are no longer available, some items are commercially available - or easily adapted from substitutes:
Spindle wrench: from www.armstrongtools.com - model #34-101.
Flat belts: from http://www.wmsopko.com/products.htm.
Bearings: check for the type needed, available through numerous suppliers.
Leadscrews: can be machined from Acme threaded stock. 5/8" - 10 Acme, left-hand for the cross feed shaft and right-hand for the vertical leadscrew.
Cross feed nut insert: this can be machined from a larger 5/8" x 10, left-hand Acme available from McMaster-Carr.
Table rack and pinion: the pinion is Boston Gear Part NB16b, 16-tooth, 16-diametral pitch, 14 ½-degree pressure angle, 1/2"-bore and matching rack; available from McMaster-Carr. You will have to drill and counterbore the mounting holes as they go through the teeth, not on the side. Be sure to counterbore deeply enough or the gear will hit the cap screws - those on the Sanford having thinned heads.
Shaft bearings - bushings or needle bearings: replace with the same from McMaster-Carr
Top bevel gears: Boston Gear part L149Y-G, 32-tooth, 16-diametral pitch, 20-degree pressure angle, ½"-bore. On the Model SGm the vertical leadscrew gear needs to have the hub machined to diameter and threaded for 5/8" - 10 Acme right-hand (available from McMaster-Carr).
 
Some pics. Feed screw is quite worn as you can see. The next two pics are the vertical ways in the back and from the front. The bottom pic is the shaft that the handle goes onto and it attached to the small bevel gear on the other side. It looks like there is a small area in the middle that is a smaller diameter than the outsides. Must have something to do with the grease zirk on the housing. IMG_20170824_100926869.jpg IMG_20170824_104348423.jpg IMG_20170824_103457451.jpg IMG_20170824_105501257.jpg

IMG_20170824_105433783.jpg
 
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No insert in the old gear.
Also, I took out the spindle. 2 bearings an E14-y and E15-y.
 
There was a broke retaining ring for one of the bearings. Not sure if it affected much. One thing I find odd is these bearings are rated for max speed of 2315 rpm. My spindle speed is twice that.
 
Some pics of the ways for those who may be interested. IMG_20170824_200708996.jpg IMG_20170824_200751567.jpg IMG_20170824_200718621.jpg IMG_20170824_200755750.jpg
 
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Here's a pic of the cross slide nut. Can anyone tell be about why it looks like it has threads?
The spindle looks a little beat up. IMG_20170824_200911561.jpg IMG_20170824_200951880.jpg
 
can you tell any better from these pics. One is the vertical screw and the other is the cross feed screw. View attachment 240460
Not really, the Acme thread form has a 14 1/2 Deg flank angle, a square thread has a 0 Deg flank angle, the difference will be obvious upon inspection. If in doubt an Acme thread gauge is available from McMaster for $23.00 and likely 1/2 as much from other sources.
 
so ok 5/8 10 rolled acme 4140 rh both rh lh taps for brass bronze from bench master tune up Idid the plastic nut on the x been excellent for a year of hobby uses so how can I HELP you are close
 
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