Re: Sherline was - Re: Magnifier primary

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Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

A
>Before you ask...  I have asked many people about the "Harbor Freight 
>class" Chinese made milling machines that go for $500 that do about the 
>same thing.  They are bigger and heavier but no one that has used them 
>seems very happy with them.  Screws falling out, impossible to adjust 
>gibes, 65.2 mil per turn wheels (extra credit if you figure out how they 
>do that ;-)) things never really flat and straight...  I keep thinking I 
>will get one to use just as a fancy drill press, but I keep getting 
>scarred off...  I know that many people love Harbor Freight stuff, but 
>twist drill bits that "un-twist"*.......  too goofy for me ;-))

The Harbor freight mills are, in fact, kind of funky. They are much heavier 
than the Sherline (all that cast iron!). Kind of tough to set up too... not 
to mention the weird lead screws.

If you need cheap milling, at lowish precisions, you'd probably be better 
off to buy a cheap drill press and an X=Y table. (probably about $200, 
tops, for both drillpress and table).

Your basic Sears/Harbor Freight/discount $100 benchtop drill press will 
have a 1/2 HP motor and a stroke of 2-3", with a Morse #2 taper spindle. 
One might be able to get collet type holders for this, but you can just 
clamp the mill bit in the drill chuck.

The cross slide vise will typically be around $50-70, and travel 6 inches 
or so. Mine has crude markings on the handwheels, maybe 0.2"/rev? (I 
haven't actually looked at the markings in a long time.


The bearings in the drill press aren't really designed to take a huge side 
load and the runout may not be ideal, and keeping the table positioned 
relative to the quill requires a bit of care (the drill press table will 
want to spin around the column), but, if you aren't cutting too fast, and 
you're always cutting to a scribed line on the work piece, holding 10 mil 
tolerances is doable.  At least you'll have a fairly good sized motor on 
the drill press.

This kind of thing works just fine for milling out slots in aluminum 
panels, cutting UHMW PE strips with slots, etc.  Fixturing is, as always, 
going to be half the challenge, especially for big work (like trying to cut 
holes in a 14x19 inch aluminum panel, for instance.  The saving grace for 
the kind of machining a TC'er is going to be doing is that you're usually 
working with fairly soft material (aluminum, brass, plastic) and not trying 
to do things like mill 2 thousandths off your cast iron L6 cylinder head.


I've heard of people replacing the bearings in a drill press with higher 
quality ones.

I've also heard of people finding/modifying a cheap x-y table for more 
travel in one direction (the one I've got only travels about 6 inches) by 
sawing apart two of them and putting the ways together with a longer lead 
screw (which sounds like more trouble than it's worth)..  If I were going 
to cobble something together to mill big stuff, I'd start looking at the 
"gantry" type scheme where you move the cutting head around the workpiece, 
rather than vice versa.  Some big linear bearing rails, etc, and you can 
shove that 100 pound cutting head around.