I agree on the respect issue.
"Grant Erwin" wrote in message
...
3000 sfm is what is used on bandsaws when cutting wood I believe.

The horsepower I was gaging based on abrasive metal cutting. After all,
this *is* a metalworking NG. The electric/gas hp equivalency I was told by
an industrial air compressor company (Quincy) when I called to inquire
about repowering an 18hp trailer-mounted compressor with electric.

The issue with safety is probably just my own fear. I have an incredible
fear of large saw blades, or maybe I should rephrase that as respect.

GWE

Laurie Forbes wrote:
"Grant Erwin" wrote in message
...

Laurie Forbes wrote:

Am contemplating constructing a wood cutting chop saw for cutting up
fireplace logs. 18" circular blades are readily available here and
would seem about the right size for the size of logs I'd be working
with. Question is, what HP electric motor would be required (about 3?)
and, what would be best RPM for the blade?

All suggestions appreciated.....

Laurie Forbes



7.5hp MINIMUM motor, and that's electric. If gas, make it 18hp.


Seems a bit large but I would be interested in how those values are
calculated. Keep in mind I won't be ripping with it and don't require
particularly fast cutting speed.

Blade speed 3000 sfm. 1.5' diameter, 4.7' circumference, rpm = 636.


I'm not sure where the 3000 ft/min derrives from - my 10" radial saw
turns about 3600 RPM which gives a surface speed of about 9500 ft/min.
Is there some inherant reason why larger blades should be a lot lower?

Figure 1760 rpm / 3 = 586 rpm, close enough, gear a 1760 motor down
3:1-ish.

This sounds *extremely* unsafe. Better type all your questions now while
you still have hands.


I realize such a saw would have to be built solidly, with proper
shielding etc. and operated with caution but I would be interested in
specific reasons why it would be necessarily unsafe (18" is certainly not
by a long ways the largest saw blade in use).

I appreciate your response but would be interested in more detail if you
could provide it...

Laurie Forbes