Back at it

[Andy Howell]

If you are not in manufacturing, you can skip the rest of this if you want.


Well, I leave for a few days and this is what I get? Oh where do I start :)

How about the mini-mill? The Y axis was jammed. The handle would not
budge for anything. Devan and I took the Y lead screw out by removing
the front mounting block. The lead screw was welded to the block. We had
to use the arbor press to get it out. It was really stuck. The first
picture shows it after a lot of cleanup. We used some 500 grit emery
cloth the sand down the galling. What caused it? Lack of lubrication.
When you have metal on metal contact, the two pieces can weld themselves
together. You can see the pits on both the block and the lead screw.
Previously there were raised ridges on both. We put some lithium grease
on it. The will keep it lubricated for awhile. The bad thing about
machine tools and grease however, is that tiny bits of metal work their
way in, forming an abrasive paste. Oil is better. Many machines are to
loose the oil. Fresh oil flushes the old contaminated oil out.

I made a couple short videos on adjusting the gibs on the mini-mill.

https://youtu.be/UTujoeL1mA4

https://youtu.be/0zznppOz1aI

On to the drill press. There is something wrong with picture two. Can
you figure it out?

The spring broke on the drill press. This was pretty dangerous because
the spindle could just come down on its own. The third picture shows the
spring after I heated with a torch to be able to bend it. I finally got
the spring back in its holder, photo four. Photo five shows why I hate
working with springs. Stored energy, meet finger tip. Ouch.

What else? The tail stock on the small lathe jammed closed. Did some let
loose a Gorilla in the shop? Shesh. Repeat after me, nothing, expect
maybe the arbor press, takes lot of force to operate. The lead screw was
locked solid in the tail stock quill. I tried heating the quill with a
torch, trying to make it expand and break loose. No luck. I put it in
the freezer for an hour and repeated the heat treatment. No bananas.
Finally, I did what I told you not to do. I used excessive force and it
finally broke free. The 6th picture shows it separated in the vice. Note
the plywood. The spindle needs to be very smooth. Scratches would be
enough to keep it from sliding freely.

Not to be out-done by the mini-mill, the Grizzly mill's switch burned
out. This was the switch George and I rebuilt awhile back. Well, the
magic smoke escaped. Fortunately we had a spare switch. Devan and I put
that in, and the mill works fine now. The last time this happened I
offered a prize to anyone that could tell me why it go so hot. No one
gave the correct answer. Now I have to come up with a prize for Devan,
as he figured it out. Each time contacts close in the switch, there is a
little arching. That increase the contact's resistance. With the motor
drawing a fair bit of current, the contacts heat up, the plastic melts
and the switch fails.

Finally, I put on a new rubber on the mill. The old one was full of
holes, ripped to shreds. This keeps the chips out of the machine ways.

Enough for one night.

Andy