Saddle "stiction"

Thanks for the ideas. I'll probably disassemble the saddle to check the sliding surfaces and the wipers.

In regards to the rack and pinion, I don't believe the pinion is the problem. The handwheel has two positions, 1) inwards towards the ways engages the handwheel/pinion with the rack and 2) outwards away from ways in which the handwheel/pinion are not engaged. In the second position the handwheel spins freely so I don't believe it is binding internally.

I will locate a more appropriate way oil like Vactra or Vacuoline. IIRC, I didn't want to buy a gallon or 5gal when I needed a small amount. My internet search probably came up with this lube as a reasonable sub.

Once again, thanks. I'll update as I complete some of these suggestions.

s
 
Save the bucks. The machine is being used in a home shop not a production shop.
ISO32, or ISO68 hydraulic fluid. Find it at a farm store.
Put the money saved towards tooling.
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www.hobby-machinist.com

Is cheaper hydraulic oil OK?

I am brand new and starting to learn. I just bought a lathe from Precision Matthews (1440GT) and will be picking it up later this week. I notice they spec Mobil DTE heavy/medium iso 68 SAE 20 grade oil. I looked at MSC and they want $175 for 5 gallons. I read several other posts on this...
www.hobby-machinist.com www.hobby-machinist.com
 
I had the same problem with my 12 x 36. The shaft that the pinion mounted on was bent. Cranking the handwheel resulted in loose tite loose tite all the way down the bed.
 
I took the saddle assembly apart today and looked at the sliding surfaces. I did not find any kind of trapped crud that would cause binding. It looked like the V-shaped area where the front way slides had an odd appearance. In my limited experience it almost looks a poorly executed scraping. It felt wavy but nothing sharp or jagged. Not much that I could do immediately I decided to reassemble and see if I could make things better.

I wiped everything clean, loosend the floating rear saddle gib adjusting screws, and reassembled. I kept all the screws loose and snugged them evenly as I moved the assembly up and down the leadscrew. The saddle moved freely until I did the final tightening on two bolts. Voila! I found the culprit.

It was the bolts that held the front saddle gibs. On this lathe, the front gibs are single piece, fixed, non-adjustable whereas the rear gib is floating and adjustable with set screws. I placed some thin shimstock aka cut up beer can between the gib and the underside of the saddle. I was then able to snug the bolts and the saddle continued to move freely. woohoo!

Problem solved. I'll switch to way oil once it arrives. Input much appreciated.
 
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