Hand Plane Vibration

[sroger007]

I am looking into measuring the levels of vibration in hand planes (specifically in the blades when mounted in plane bodies and potentially in the plane body as well). These are metal bodied hand held planes one would find in a woodworking shop.

Subjectively the vibration frequency one can feel in the"hands" seems very low - I'm guessing in the 60Hz range. As I have no baselne to compare to I'm thinking a general purpose low frequency mini piezoelectric device should suffice. My only concern is the shock levels the device would see as the blade hits wood knots etc. I don't care if I can't measure it I just don't want to damage the device. Is there a particular type of device I should look at? I have realestate constraints about 1/2" square is the upper limit - side mount

My plan is to run this through an oscilloscope - as I can easily rent one of these puppies.

Any input would help - Thanks

 

[MikeHalloran]

Use metal foil tape to strap an accelerometer to the plane body.

Rent a _digital_ oscilloscope, so you can record the waveforms and process them later.



Mike Halloran

http://www.deangelomarine.com

 

[hacksaw]

tape a microphone to the plane and monitor it with your sound card

there are a number of freeware software pkgs that will reduce the dat,

have fun

 

[GregLocock]

If you use a conventional piezo type acceleromter then it will easily withstand any vibration that a human can withstand. The smaller ones are rated for 5000g and can be used inside artillery shells.

A 1/2" accelerometer (B&K 4371 off the top of my head) will be fine for your purposes, although you may want a triaxial unit in which case your problem will be lack of sensitivity rather than the reverse.

Are you looking into 'white finger' ?





Cheers

Greg Locock

 

[sroger007]

Greg,

White finger is a thing of the past with most of todays current planes. I'm looking into smaller increments of vibration - I'm not even sure there is measurable vibration on a good plane. However people who use these things are so sophisticated they measure flatness with CMM's and draw relationships to planing quality. I want to understand vibration levels and then see if there is any relationship to planing surface quality. If so I will explore reducing/eliminating it through blade thickness, blade bed contact area, etc.

Thanks for the input. I'll be using a single axis device

Scott

Scott

 

[sroger007]

Mike

Thanks for the tips. The digital Osc is a good one. I'm a little out of my elemnt here.

Scott

 

[sreid]

Go to Tektronix

http://www.tektronix.com

and check out the TDS1000-TDS2000 Digital Storage Oscilloscopes -DSO's.

 

[Rob45]

Try hacksaw's idea first: use the analysis capability in Cool Edit 96, freeware available at among other sites,threechord.com.

 

[sreid]

The Tektronix scopes have a built in DFT so one can immediately get a frequency spectrum from the displayed time domain data.

 

[chscholz]

Are you trying to measure vibrations in "normal" operating mode or vibrations due to "chattering" (vibrations of unsupported part of the blade that leads to engaging and dis-engaging of the blade with the wood)?
Since you are probably interested in the eigenfrequencies of the blade (and not of the plane body), I appears that mounting your sensor as close to the cutting edge as possible might give you the most useful measurements.
You probably want to consider various factors including type of plane (block or bench), sharpness of blade (difficult to measure objectively!), thickness of blade, lenght of unsupported blade, bevel angle, frog angle, mouth opening, type of "chip breaker", type of wood you are planing, ...

 

[sroger007]

chscholz

Primarily intersted in the blade but will need to understand relationship of the body. Getting as close as possible to the unsupported area of the blade in front of the blade bed is my starting point. You seem to know your plane anatomy. Not aware of much material on this so basically starting from first princples