lathe_explanations

Lathe explanations

Explanations of unclear material, typography corrections, drawing corrections, and elaboration on what may have been left out goes here.

Q1): In the Holy Orange Book Of The Lathe, Dave (blessings be upon
him) says that the two outer gib screws are "pointed" and that they
fit into the dimples "formed by the tap drill". Now - I assume the
latter means I should have the gib in place when I drill the holes,
and that I should drill just slightly into the gib, so just the tip of
the drill bit leaves a kind-of-countersunk dimple in the gib piece --
is that what y'all have done?
A1 - Pretty much right on the money. When I did mine, I used the
drill to 'mark' the key stock and then used a 1/16" bit to make a small
dimple.*1
A1 All I did on my lathe and mill was use a 10/24 set screw hand ground to a
point to make a small dimple in the gib after the holes were tapped.The set
screws are plenty hard enough to make a mark in the gib as they are
tightened.if you want you could always centerpunch the marks made by the
screws to make them deeper but i never found it necesary. *2

Q2): As to the "pointed" screws -- he doesn't really specify the
screws other than that they're 10-24 x 3/4". I assumed he meant
"machine screws" or "stove bolts" -- which are flat-ended, as far as
my experience goes. I looked around for pointy-screws (e.g.
sheet-metal) that fit 10-24 threading, and they don't. Any help, here?
A2 - Take your gib screws and grind a point on the end. I chucked
mine in my drill press and used a file to do this. It did a decent job
of keeping the points concentric. The gib screws I use are actually set screws. Set screws can be easily chucked in a drill without damage to the
threads or the difficulty dealing with a head. *3
A2
A2 I don't understand why you boys are making things difficult for yourselves.
Just get some cone point set screws from MSC or ENCO and be done with it. *4

Q3): what kind of lock-nuts did people have good
results with? Split-washer and nut? Jam-nut? Crown-nut w/ poly insert?
Scalloped nut?
A3 - I, like most people, use plain flat nuts as jam nuts. Keep in
mind that the jam nuts only keep the gib screws from turning. Very
little torque will be required to do this. *5
A3 My southbend lathe doesn't have locknuts on the gib screws but my
Burke Horizontal mill does so I guess they aren't critical. Anything
that will keep the screws from working loose but doesn't interfere
with adjustment will work. You could just center punch from the
underside to put a dimple in the side of the threads. That would
make the threads tight enough to hold without a lock nut. *6