Just went throught this with my 6" beaver in the post below.you are in the ballpark,maybe on the low end but acceptable.in researching to set up mine most three knive cutters I found reference to seamed to be in the 3500 to 4500 rpm range

 

UPDATE...I found the manual...

It calls for a head speed of 4000 RPM with 6.5" drive pulley and 2.75" head pulley...

Are these standard sizes...? Should I slow it down...?

 

FWIW The Shopsmith/Magna 4" jointer suggests the following speeds:

Finishing Cuts-----Hardwood-----Softwood
----------------------5300 RPM------5200 RPM
Heavy Cuts--------3900 RPM-------4550 RPM
Min Speed---------3900 RPM
Max Speed--------6200 RPM

I would say that 4000 RPM is a bit slow for finishing cuts/jointing

 

Thank you Al...I'm finding the same...

Since I would only be using it for edge cleaning (<1") I was wondering if I could run it slower...bearings are cheap ($3.99) but retainers are not ($146)...go figure

EDIT...I went back through your post...nice looking machine...hope mine comes up as good...I especially like your stand...

 

If you compare to modern machines most will give cuts/minute among the specs. Divide that by the number of knives on your head and that will give the rpm you need the cutter head to turn.

 

I have a old (1950's) 4" craftsman and they recommend 4500 rpm so 4000 sounds ok

 

you can get manuals at vintagemachinery.org

 

Another 'toy'!
https://www.princessauto.com/en/detail/digital-laser-tachometer/A-p8714933e
Everybody needs one...

 

you make it sound like it's a bad thing...
I have that in analog and laser...

 

Your settings are good enough.
Running it slower will make more little undulations or then slow the feed rate to reduce undulations.
(Some machines are built to reduce this by having more cutters like 3 blades)
.
There is also an optimal speed for wood cutting, but that one is not RPM's,
That is a linear speed , the speed the blade cuts.
Too slow is not optimal, especially on soft woods , to fast can make burns on wood.
This is the speed the blade travels :
A 3 inches diameter cylinder will give 3" x pi (3"x3.14) = 9.42 " per turn
This is to be multiplied by speed of turning:
9.42 x 3500 =32970 inches by minutes
to be converted in inches by second:
32970/60 =549,5 inches by second
or in feet per seconds:
549,5 / 12 =45,79 feet/second

This is about 14 m /s for the metric users or about 50 km/h or 30mph very normal.

(The cutting speed is less critical when woodworking than when cutting metal.)

This article might be interesting:

https://en.wikipedia.org/wiki/Speeds_and_feeds

Regards.
Gérard

 

Sounds like you have way more than enough power. I think my 50's Craftsman 4" runs fine on 1/2 or 3/4 hp.

Sent from my SM-G900V using Tapatalk

 

Here's a Calculation table for Speeds with different size Pulleys. You are close enough though with your Calculations. This is from VintageMachinery.org website, great Website for Research for Old Woodworking Machines. Calculate Arbor RPM | VintageMachinery.org.