Subject: Grinding ways

From: NJRich <[email-masked]>
Date: Mon, 09 Dec 1996 18:31:15 -0800

Warm greetings,

I have this Sears (atlas)  12" x 36" and the lathe bed does have in
the neighborhood of 1-4 mils of visible wear ( I haven't cut with it
yet to be sure). I read recently here about concerns with grinding
to eliminate lathe bed wear. The lathe in general is a snap (aside 
>from  the mass of the parts) to take apart and the ways are just two flat
rails. Also if I jump through a few flaming hoops, stand and my hind 
legs, bark at the moon and deliver some fresh pastries there is a large 
machine shop Iknow that may do the grinding at no additional charge!.

My question is should I go ahead and try to get this grinding done, try
and live with it or try and get another lathe. I would like to work 
within reasonable tolerances not any world records but at least near
professional work.

Thanks a 1,000,000

Rich

---

From: [email-masked] (Fitch R. Williams)
Date: Tue, 10 Dec 1996 05:23:50 GMT

"Les Whitaker" <[email-masked]> wrote:

>And I thought I was the only one...
>Les Whitaker

Not even close!  This is a whole group of "ones".

Fitch

>Reckless <[email-masked]> wrote in article
><[email-masked]>...
>> [email-masked] wrote:
>> 
>> >.....ANd then sometimes you can make a $5.00 tool out of $100.00 worth
>of
>> >material and many hours of labor.  But then if we knew what economics
>was
>> >all about we wouln't be running a lathe would we?
>> 
>> Don't I know that one.  To make a small (1.5 gallon) air tank, I
>> needed at TIG welder.  $1700 for the TIG, $27 worth of scrap aluminum
>> and I have a very nice tank.
>> 
>> A lathe and mill are on the horizon.  My project car is getting
>> expensive.
>> 
>> -Reckless
>> 
>>

---

From: "Les Whitaker" <[email-masked]>
Date: 9 Dec 1996 22:13:07 GMT

of
was

---

From: [email-masked] (Jonathan M. Elson)
Date: 10 Dec 1996 06:24:05 GMT

NJRich ([email-masked]) wrote:
: Warm greetings,

: I have this Sears (atlas)  12" x 36" and the lathe bed does have in
: the neighborhood of 1-4 mils of visible wear ( I haven't cut with it
: yet to be sure). I read recently here about concerns with grinding
: to eliminate lathe bed wear. The lathe in general is a snap (aside 
: from the mass of the parts) to take apart and the ways are just two flat
: rails. Also if I jump through a few flaming hoops, stand and my hind 
: legs, bark at the moon and deliver some fresh pastries there is a large 
: machine shop Iknow that may do the grinding at no additional charge!.

: My question is should I go ahead and try to get this grinding done, try
: and live with it or try and get another lathe. I would like to work 
: within reasonable tolerances not any world records but at least near
: professional work.

Unless your friendly local machine shop has a grinder in absolutely
perfect condition, and the guy who sets up your lathe bed on it treats
it as if it was his own, you may not get it any straighter than 1-4 mils,
anyway.  If it is one mil, absolutely DON'T try to grind it.  Vertical
wear is of least importance in a lathe, anyway.  The front/back wear
is most important.  On a lathe not equipped with inverted Vee ways, then
the only thing constraining the carriage are the front and rear vertical
edges of the ways.  These don't wear all that much, unless the gib is
overtightened.  Still, I wouldn't get too excited over wear of no more
than 4 mils.  Assuming the wear is evenly distributed front and back
(which might not be the case) that leaves only +- .002" error in
carriage position.  All this will do is allow long cylinders to have a
slight barrel shape.  if you need to turn long shafts to precision
diameter, one wonders why you'd even get an Atlas.  But for general
lathe work, your machine is probably in quite good condition.  When people
on this group report areas worn down .030" on their bed, then you KNOW
it needs work.  I'd get the lathe running and see how it does on work
of the sort you expect to be do.  Of course, if your friends really have
experience grinding lathe beds, you might take them up on it.  If they
would be doing a favor, and don't do this kind of work regularly, I'd
be a little leery.  First, they need to have a surface grinder big enough
for a small lathe bed.  Most smaller shops don't have a grinder this big.
Second, they need to have the right size and shape wheels and mounting
jigs to set up a lathe bed on the grinder, and be able to true it up with
the grinder's axes.  You don't want them cobbling up something with a bunch
of bolts, nuts, washers, wedges and assorted junk.  If it gets loose, you
could have your lathe bed shot through a concrete wall, and your friend
explaining to his boss why they need a new $50,000 grinder!

Just a few thoughts from the overly cautious.
						Jon