PT Cutterblock RPM

[dicktimber]

I notice that one of the planerthicknesser manufacturers (record PT 310)quote Cutterblock RPM, then state the cutter blade RPM, which is lower than the cutter block RPM.
My Father in Law a retired engineer, insists that the cutterblock and the knife RPM should be the same as they revolve at the cutter block RPM.
He insists the knife RPM stated has been calculated using distance travelled rather than RPM, which is fixed by the cutter block RPM.

IS he correct?
My brain hurts trying to fathom it out!

Mike.....

 

[Maverick.uk]

Something is wrong somewhere, if the spindle is turning at 1000 rpm then everything on it is travelling the same amount or revolutions.

You sure it is not quoting something slightly different and there has been some mis interpretation?

Do you have a link to the info?

Thanks

Mav

 

[neilyweely]

Sounds like your father in law is correct to me, but what do I know, I am a humble chippie!!

Will be interesting to find out!!

Neil

 

[jasonB]

Are you sure one of them is not FPM - feet per minute, this would be the periferal speed of the blades which I would expect to be lower than the RPM as the block is likely to be less than 100mm dia

Jason

 

[dicktimber]

The spec as published in Nicks , British Woodworking FEB/March 2009 back cover page Record Power ad for PT300.
Spec states
cutter block speed 5300 rpm
blade speed 4000rpm.
I expect it is periferal speed.

Mike

 

[jasonB]

That would be about right for a block of just under 3"

3/12 x 3.142 x 5300 = 4163 Feet Per Minute

Strange that they don't have that model on their web site

Jason

 

[Maverick.uk]

I expect it is periferal speed.

Mike

In which case rpm is the wrong unit.

Quick calculation for a cutter block of 3" (i dont know the size just guessing) with an rpm of 5300 on the spindle gives 4161 Peripheral Speed: (feet per minute)

see here
http://www.haskinsindustrial.com/en/cal ... heralspeed

Cheers

Mav

 

[Maverick.uk]

Strange that they don't have that model on their web site

Jason

Yeah i checked the web site too, its actually PT300 in the book not 310.

Cheers

Mav

 

[dicktimber]

Sorry for the incorrect info, it is the PT 300.
It would be interesting to know if it was a Record power cock up or a misprint at the publishers end?
Thank's for the help

Mike