Step 8, Mounting the block
The crane is great for lifting heavy tools and workpieces,
picking up the block like this was simple.
Step 9, Powering the machine
If a steel or concrete table is to be used for MultiMachine,
make certain that it is wide enough to have a two foot space
off to one side to use for the drive unit. If possible give the
drive it's own table since that is a good way to suppress
vibration. If the drive is to be attached to the side of the block
then it is easier to build it while the engine block is turned on
its side. Be careful here because the heavy swinging electric
motor is very hard to handle. The motor and its mount can be
dangerous.
If you plan to use the machine only as a horizontal mill used for milling iron or steel then a single
50 to 100 rpm speed range is needed but may take six 2 grove pulleys. If you want a very useful,
simple general purpose lathe, end mill and drill then a single 450 rpm speed is a good choice. I
have found that this speed also works well on aluminum with a three or four inch horizontal
milling cutter. Use three inch and twelve inch two grove pulleys to get this speed. Grizzly tools
has some very nice cast iron pulleys that will work here. Why two groove? Three groove pulleys
with matched belts would be even better but are much more expensive and also are also hard to
find. Getting a 100+ lb. spindle up to speed with a 2+ hp motor causes a lot of noisy belt slipping
with just a single belt.
If you try to use cheap zinc hardware store pulleys you may find that they soon fly apart! For
more reduction, fit in a small truck transmission that has an extra low first gear. The best but
$300 answer is a VFD (variable frequency drive) 3hp motor and a 2 speed (4 pulley) belt
arrangement. This could give you a high range of 300 to 3000 rpm and a low range of 50 to 500
rpm. The MultiMachine idea is to do everything as cheaply as possible so this goes against the
grain a little but if you have money to spend, this is a good place for it to go. After thinking about
all this, the single 450rpm speed may sound better and better!
A warning about belt drives and aluminum pulleys. For many years I worked on large
industrial belt drives that used iron pulleys and never noticed a friction problem. However, just
slightly increasing belt tension with the multiple aluminum pulleys will make my machine bog
completely down to a stop. This is another reason to start with a single 450rpm speed.
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