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Yeah good call Mike and yes the motor is 1 HP.

My plan is to only capture the buffing wheels with the pulleys enough to keep them turning well but leave enough 'slack' in there to compensate for all the torque and hopefully being able to 'stall' it by having the wheels slip within the pulleys. And, from what I'm gathering, 1000 is a little too high RPM for buffing as well. Only a plan up to now so we'll see how it ends up. Also though of slowing the RPM's but as you suggest the torque will still be a problem.

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Parma?

When I'm in a hurry, I use one of these...

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

What are y'all going to buff with these things?? Why so big? I'm still perfectly happy with my little StewMac setup(their original one, not the new, larger one).

You do realize that the longer the shaft is, the more pronounced any slight imbalance will be, and that no buff is ever perfectly balanced, right? And keep in mind that as the shaft and buffs get heavier, you'll need more power to simply get the thing going, and once going, basic physics will take over and even if you have minimal power, inertia will still prevent the buff from slowing in the event you lean-in too hard, or, god forbid, you present an edge and it grabs your work and slams it(hard!) to the floor.

That said, any machine shop, or for that matter, anyone with a decent size steel lathe can easily cut the threads, both right and left hand, so all you need to do is go to a steel supplier(ever city has many) and buy a raw shaft. Heck, any decent machine shop will have the shafts on hand, for that matter.

Where in the world is that thing? I would like to see it in operation.
Actually, I'd like to see the shop it's in!

I am going with -12 thread, like the Parma (it can also take the Weninger arbor adapter that way)

http://oarenj.com/prd/catalog/product_i ... ucts_id=47

Gotcha.

But the larger shaft, while minimizing flex, still won't help with the balancing of the buffs. I'd place the bearings as near the buffs as I could get away with, and with the large diameter buffs, they could be just about -at- the buffs.

Balancing may not seem important when you spin them at 600 rpm, but if you get into polyesters and such, you'll want to spin them at 1500 to 2000(I run mine at 1:1, or 1725 rpm) and balance then becomes a real issue. The larger the buff, the more pronounced the out of balance will be, also. You might be able to balance it all by using a hose clamp and a little chunk of lead or two, by trial and error, if need be, I suppose.

Too bad y'all don't live nearby; my lathe(a Harrison M250) can take a 1-1/4" shaft; cutting threads would be a 2 beer task, at worse...

any machine shop should be able to do that. Simple quick and easy. If they don't have capabilities for that I would run away.

I wish I knew how to do threads on my lathe - mine are a glorified wood lathe...

Just tried our latest batch of dark red with Yerba Matte (1 lb. for 5 gallons)... that is not a six pack I'd do in one sitting.


(I've been wanting to use that emoticon)

Anyone get any quotes on machining a shaft yet? I'm still waiting to hear back on my end...

I see. This economy has run a lot of places out of business. Hopefully you can find one. That's a pretty simple job once you find a shop. Depending on your tolerances I'd say you are looking at about $40 in machining plus material. Possibly cheaper than that.

Being a newbie, I'm just building my own, and going off of what seems to be the best value I can come up with.
When I saw that Grizzly sold 16-20" wheels for not much more than the smaller ones, I figured I'd get as close as I can to the wheels the big boys use. But since FPM is obviously an issue (I calculated it needed to stay below 2700fpm?) I tried to gear it down to less than that.
I also keep hearing about how handy it is to have longer shafts, so that you can work the body around the wheel without banging into bad things.

Mario, what size wheels are you turning at 1725 rpm? How much adjustment do you have in your system?
I was trying to get mine to have three speeds, set up to be the same fpm for 16-20" wheels, and some up or down if I played with the wheel/pulley combinations. (I also didn't want a huge pulley on the buffing shaft, thus I went with a double belt system).

If I'm missing something here, please let me know.

Okay, where do I send the case of beer to?
I just got a call back from one machine shop, and I don't think they want to do the work.
Quoted 2.5 hrs at $90/hr!

BTW, also said they don't want to thread a shaft that already has a keyway at the ends (might have to return some of my Mcmaster order and rethink this).

I would be game for going in with a few others to have a shaft machined, if you can get a better deal on the work.
Is it legal to mail 'home brew' across state lines, as payment? If not, I have a few extra federal reserve notes (supposedly the same as money) that I can send...

that is an absolutely insane price! The $40 I approximated was for cutting threads, keyway, two tight tolerance areas for the bearings and turning the entire length of the shaft for concentricity. Of course there would be about a $50 set up cost. So you are looking at $90 for the first one and $40 a piece after that. Plus the cost of some cold roll steel. Whatever shop you contacted was just quoting you a crazy number to scare you off cuz they don't want the work.

That's what I figured... but I'm in California, where most people deserve to get paid not to work, and those who do work deserve to get paid triple (so they can have some left over after they pay for those who aren't working).

HELP!

Having escaped from California and moved to Tennessee about 14 years ago I can verify that there are some major price differences.

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Steve Smith
"Music is what feelings sound like"

That's a good point; if the blocks are right next to the wheels, it would be virtually impossible to hit them (the angle would be too steep). I guess it's just that most systems have a central casing that you want to keep a guitar body away from, thus the desire to cantilever the wheel as far out as possible. Nonetheless, there has to be some sort of pulley on the shaft, and it either needs to be in the middle (equadistant from from both buffers) or also right next to one of the buffing wheels. The shaft will always be in the way to some degree, but if you can keep everything else away as well, that is ideal.
Thus, if you built some sort of metal frame that the pillow blocks bolt to, right next to the wheels, and the frame is behind the shaft and almost no wider than the pillow blocks, then everything should be close to ideal. Other than the pulley, you wouldn't even need the shaft to be that long - just want to make sure the body won't ever touch both wheels at the same time (or in the same movement).
That definitely gives me some more to think about in the design.... but since I'll probably keep the pulley in the middle (to balance torque) I'll still probably go with a longer shaft; I have a 48" which seems about right with the 7" pulley I have.

I'd like to hear what other people's layouts are going to be.

Just a quick update: Today I received my 1" x 39 3/8" axle that I paid $14.95 for. From initial inspection I'm very pleased. The machining is nice and crisp. Threads were well protected for shipping. I can't tell yet with any degree of precision but, sighting down it, it seems very straight and it rolls just as straight and true as you could want it on a flat surface.

The only flaw I could find with it is that it isn't coated in any sort of protectant so it does have one spot of light surface rust about the size of a dime. I think I'll live.

I'll be a bit surprised if this doesn't do the job quite well. Again: $14.95. I don't know how or why but so far looks good.

For me, it's because I am planning on mounting the pillow blocks vertically instead of horizontally... I want the shaft to be the furthest most part of the system sticking out from the wall, not the frame. And for that, I trust metal more (probably not the best reason, but then I also have a full metal shop that can make it for me, so it's almost as easy).

However, with the pillow blocks up against the wheels, that 1" shaft is starting to look very appealing - as a step-up bushing is easy enough to slide on for the 1-1/4" buffing wheels (and pulleys are much more common - and less expensive).

Where is a good place to get 16-20" wheels?

Any further discoveries on getting larger shafts machined?

I couldn't pass up the 1" x 39" axle for $14.99, total $20 and change to my front door. My current buffer has a 3/4" shaft and a short axle, so I was looking for a little more room for buffing. The 1" go cart axle turns out to have about .015" run out, so I may have to redesign and move the bearings closer to the ends. Also, I am not sure how well the lock nuts will hold since both sides are right hand thread. For now, I am going to give it a try as soon as I get larger diameter buffing wheels. Here's a couple of pics of my simple buffer minus the motor and on/off switch...with welding required;

Chuck

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I talked to that axle shop on Thursday, and they said that they would machine a solid 1.25" aluminum axle with L&R threads for about $55-60 each (I told them we might do multiple).
However, though AL is stronger than steel, it is three times more flexible, so even with the larger diameter, the bearings may need to be much further outside. On the other hand, my structural engineer (who races motorcycles and designs some race car stuf) thought that racing cart axles 2would probably use alloys that have similar stfifness, and thus may be okay? Unfortunately, they don't stock 1.25" solid steel, and the owner won't bring it in for a small order. But they may be willing to thread their hollow steel axles... they have 1/4" wall thickness, which should leave plenty of material under the threads for some buffing wheels to hang of of. I hope to find out on Monday.

BTW, I am having a batch of 18" 16ply (1.25") buffing wheels made.; medium, fine and extra fine. If anyone wants to tag onto the order, I can have them shipped to you (minimum of 4).
I will get pricing next week (should be less than $25 each).

Aluminum is not stronger than steel unless you are factoring the strength per weight basis. But in an application like this, weight is not really a consideration.

How many of you guys use ventilation fans behind the buffing machine?

Well guys, for lack of further input from others, I've pretty much decided to go with a 1.25" aluminum shaft, threaded with both left and right hand threads. I am going to move my bearings out toward the buffing wheels, so that the flexibility of the aluminum is not an issue. Plus, I like the lighter weight of the AL - but the $75 cost for the machined shaft is the major factor!

I am ordering my shaft to be 44" long, for two reasons. First, since the bearings and pulley will be next to the buffing wheels, there is no big hump in the middle of the machine that I have to keep the guitar away from, and thus can let the machine have a narrower stance. Second, I wanted to design it so that it could be stored in a standard four-foot shelf when not in use (I actually have some cabinets that I will keep it in, so that it won't get loaded with dust from my home shop, which is mostly in one room).

A couple of questions.

1) Since my pulley is going to be fairly close to one of the buffing sides, how far away should I safely keep it so that I don't have to worry about the buffing pad hitting it (when it is flopping around, getting up to speed)?

2) What recommendations would you give for how much thread I should put on each end?

Thanks in advance for your advice. Once I have this nailed down, I hope to get building.
If you have any last minute changes/suggestions for me, now is the time to speak up or forever hold your peace!

Update for those thinking on using the go cart axle. I have mine finished and buffed 4 guitars with it so far with no complaints. It seems that only 1" of right hand thread is all that is necessary if you use locking nuts on the threads and locking collars on the inside flange. I know that 4 guitars is not enough to be conclusive, but so far I have not had any loosening of the locking nuts, and the locking collars (from Mcmaster Carr) have not moved and are made for using a wrench on them. Also, the go cart axle I received has .015" of run out, which is undetectable when running free and/or buffing. I am using 12" buffs from my old buffer and plan to go to 14". Also, running a 1/2 hp motor. Here are a couple pics of how I use it now...still need to mount it permanently.

Chuck

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