Official Luthiers Forum!

I ordered mine last night. I have two home made micro turn buckle jacks but this thing is too cool and a great idea. At least from my point of view.



On an other note the new buffing arbor w/ motor is out and as I thought the motor is a 1725 rpm/120v but they don’t say what HP. Keep in mind that with the sheave reduction you do not get 1725 rpm at the wheel. The don’t say what sheaves are on the arbor or motor so I am not sure what the max rpm at the wheel is.

Where does one get this way cool stuff Michael?

C'mon, Hesh, take a guess!

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Same place my so so guitar plans will soon be available at

At MacDonald's! Thats Stewart MacDonald's Not Ronald

I've seen the jack at the Montreal Guitar Show... seems very well made. Controlled myself and did not buy since I don't do much repairs...

I think the new arbor kit will use 14'' buffs... thereby increasing the "tip" speed of the buff...

Yes it will use 14" buffers and they increased the length of the shaft by 6"

But stop and think for a second. If a 14" wheel is attached and fixed to a shaft spinning at 1100 rpm how fast is a 14" wheel spinning at the periphery of the wheel? Now if a 12" wheel is fixed to the same shaft, how fast is it spinning at the periphery?

Of course Michael... they have both the same rotation speed... but there will be more "buff" touching your guitar per minute if you use 14 inches buffs... so more heat generated... so the rpms should be lowered. But you already knew that!

Now this is a true statement. I just was not sure if you assumed that the bigger the wheel diameter the faster the speed at the wheel.

Now a larger diameter of wheel the more the contact area at that rpm more heat is generated at a given amount of pressure applied.

These do come with two input sheaves on the shaft for variance in speed.

Happy to agree with you...

Thank you for having allowed me to pass the 100 message mark...

The number of rpm's remains the same, but the tip speed of the bigger buff is about 16% higher than the tip speed of the smaller one.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Define what you are calling tip speed. the both complete a revalution in the same time so the tip speed in regards to the arc of travel is the same. If they were wheels on the grond and covering a distance the 14" wheel would cover more ground in one revalution that the 12" but that is a factor of diameter to the flat plane of travel.

Tip speed meaning that with a given rpm, the larger circumference of the 14" wheel means that the tip has to move faster in a given amount of time to complete the same arc, because the arc is longer. Or, in 1 minute @ 1100 rpm, the tip of the 14" wheel travels 52,575.6" vs. 45064.8" for the 12" wheel.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

This is true. You are refering to feet per min or second whatever unit you wish traveled not RPM these are indeed differnt that is why as I said a bigger diameter will goes further in one revalution.

Tip speed? In machining, the term is surface speed, it eliminates RPM variance as relation to work being done.

One thing also is the surface speed of a buffing wheel is constantly changing due to buffing wheel ablation, or fibers worn down in use effectively making the wheel smaller.

I've heard the numbers 300 RPM bandied around in relation to finish buffing wheel use, that would give a surface speed at about 18fps(feet/sec) for a full sized 14in wheel at 300 RPM.

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Billy Dean Thomas
Covina, CA

"Multi famam, conscientiam, pauci verentur."
(Many fear their reputation, few their conscience)

What you guys are discussing is the difference between angular velocity (RPM or radians/sec or degrees/sec) versus Linear or tangential velocity in ft/sec. Ya'll are engineers arn't ya??

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Steve Walden
Aspiring Builder,
Bartlesville, OK

The term you are talking around is Surface Feet Per Minute (SFPM).

Tip speed means the tangential velocity at the radius of the buff (r x w)

The tangential velocity is 16% higher for a 14" buff (over the 12") as already noted.

Although the tangential speed increases with buff radius, the reverse torque applied at the buff edge also increases making it possible to stall the machine.

Mike

Will bet a nickel that it is 1/4 hp. Do all here think this machine (complete system) is a good value at $465?

Mike

Yes Mike These are the proper descriptions. I actually looked in 4 different text books, theoretical mechanics, theoretical physics and a couple on application of mechanical engineering. There is no definition of “tip speed”. I just want to know what they were calling tip speed. Waddy’s explanations was good, basic and understandable to the layman.

I might have used the wrong term, but I said it was 16% faster. So there!

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I bought the jack right after GAL. Very cool tool. Has been useful in repairs many times so
far. It can also lift my coffee to my face when it is very early in the morning.
Best, Evan

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http://www.NewYorkGuitarRepair.com

I like the term Tip Speed. Kinda makes more since to me. Anyway, how fast with the tip be speeding the first second as compared to the second second if it's falling off the Empire State building in a vacuum at sea level during a full moon?

I love you guys! You make my brain hurt.

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"After forty-nine years of violin building, I have decided that the search for a varnish is similar to the fox hunt. The fun is in the hunt."
Jack Batts Maker and Repairer of Fine Violins

Back to the value question for the buffer. $465?

Motor: ~$100
36" Go-kart axle: ~$100
Pillow Block Bearings(2): $30
Multi-Diam Pulley: $15
Motor pulley: $15
Belt: $10
Buff Sticks(2): $50
Buff Pads (14" + arbor hardware):$75 Total ~$400

Still have to build a frame and protective cover for belt & pulleys.

I am basing my guesses (rough) on stewmac.com, casewell.com, and mcmaster.com

I think Stew-Mac did their homework.

Mike

That ought to be able to pop the top huh?

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Tickle your guitar daily, and it'll tickle you back.

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