Re: are 3/4 shafts good for axis ?

Dave,

Three key questions- What sort of tollerances do you need to hold and
what sort of finish do you want? What do you want to make? Axis
travel length would also have some impact on the rail.

I have a retrofitted mill and a home made 3 axis router. Both aren't
like a big rock solid closed loop servo unit but they serve my needs.
Much depends on what you are making and the tollerances and finish you
need. Another issue is feeds. I can't hog material at 30ipm on my
machines but then I don't need to.

My shop is geared to make things and I don't build, buy or use a machine
with out considering what I am going to make and the cost involved.
What one fellow considers a junky machine might serve another fellows
needs.

Most of what I make on my little mill are tiny metal casting patterns or
simple parts which have to be reasonably accurate. The parts I make on
my less than precision router are fine if they come out within a few
thou or fit together properly. In both cases I sometimes tweek my
program to get more accuracy. Often I run a few test parts, measure
and then tweek the program and run the parts.

Build a machine that fits your budget and needs. If this is mostly
just for fun, build cheap and do some learning before you spend the big
bucks on building the dream machine.

I buy parts off eBay and have had pretty good luck. I especially like
Thompson "super slides" which seem to be a good value on the used
market. I also use Thompson 5/8" transportation grade ballscrews with
reasonable results. Most of my parts are less than 12" long though I
often rout them from 24" long planks.

Jack





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