Dynabrade Dual Action Buffing Head

Kevin Brown said:
It's a quality piece of equipment... shouldn't pose much of a problem for any decent rotary. Now, the weight of the pad... that's a different story if you're using something larger or heavier than a 9" double-sided pad. I'll be using it with a Makita 9227C. At such a low price... I bought one, too!
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Yeah, amazon.com has them right now for $180 with free shipping... I just *know* that this is exactly what my wife wants for Christmas....
 
Accumulator said:
Ah, that's a change for the better!



What's the practical minimum, given the overall size of the thing?
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The Dynabrade housing measures 4-3/4" in diameter, and its backing plate mounting spindle is offset 3/8" (thus developing a 3/4" diameter stroke). If we were able to center some sort of adjustable diameter disc directly over the bottom of the Dynabrade attachment , set it to 4-3/4",and then move it 3/8" either way, we would need to add 3/8" to the diameter to cover the housing opening.



So... by my calculations... 4.75" + .375" + .375" = 5.50"



A 5-1/2" diameter backing would be required to keep the spinning parts covered.

No reason to lose a digit. You'd be stuck doing "High Four" instead of a "High Five". :hifive:



That seems about right, judging from these pics:



The aluminum housing measures 4-3/4” in diameter.



dynabrade1.jpg




dynabrade2.jpg




The Mirka #106GG Backing Plate measures 5-13/16" in diameter (lower left in the photo:



dynabrade9.jpg




Here is the Mirka #106GG installed.

Look how close the edge of the backing plate comes to the edge of the Dynabrade attachment:



dynabrade19.jpg




dynabrade20.jpg




That's it. :wavey
 
Kevin Brown- Ah, OK, thanks for the info.



Think it puts an excessive amount of stress on the backing plate's spindle (or should I say "threaded stud " :think: )? As in, causing a need to select the plate with great care?
 
I don't think it will, as long as the plate is a tried and true model.



Not sure which places more load upon a plate and stud:



  • 5/16" diameter orbit @ 6,800 OPM (common specs on the random orbital's we typically use), OR
  • 3/4" diameter orbit @ 3,000 OPM (common top speed of rotary machine's we typically use)

I think on paper, the Dynabrade might be creating a bit more speed at the spindle location, around 5.9%. But then, I suppose we might want to account for how much moving mass we have, too. The machine with the heavier mass would perhaps push through an opposing load easier. Would we find ourselves adding downward pressure to the other machine in hopes of creating a similar amount of cut? Or, just polish longer. If we add pressure, how does that affect the backing plate stud? Hmmmm. :wall



Man- there's a lot of math I don't want to even try to get into!

Well, I do want to get into it, but am not a mathematician, nor an engineer.



I'd love to ponder all the possible forces and speeds and whatnot, and give those numbers to a mathematician, or an engineer... it would be great to know all this cool stuff! :drool:



But then, once again, I am over-analyzing the answer to a simple question.

Make sure the plate is tight, and there's a sufficiently-sized washer to distribute the load:



dynabrade4.jpg




Dynabrade uses a sturdy washer on the bolt that holds the plate to the machine, on and the backside of the backing plate itself:



dynabrade8.jpg




Should be good-2-go.
 
Kevin Brown- Heh heh, I for one seldom worry about people *over*-thinking much of anything ;) And yeah, the stuff you were pondering is exactly what I was wondering about too. And yeah, I too wish I had the knowledge base to make a firm determination, just...well...because ;)



So the Dyanabrade plate uses a separate screw instead of an integral stud, huh? I glossed over that when looking at the pix :o With the sturdy washers that strikes me as more secure than even the riveted "normal" plates :think: You use any thread-lock stuff or does it stay nice and secure?



So (back closer to topics others might care about), with the Dyanabrade and products like M105 you're not applying much downward force? (I'm thinking of foam pads here, not the SurBuf-types where you wouldn't want to bend over the "fingers" too much.)



Any experience with the Dynabrade machine (as opposed to the head made to fit on a rotary)? It looks like a nice, handy unit.
 
Got my Dynabrade today!



A funny thing occurred the other night after I placed the order, they called to make sure I ordered one? They stated they got a bunch of orders all over the place and wanted to make sure they were legit! The power of a forum, a sale, and Kevin Brown!



Cheers,

GREG



I don't know when I'l try it, as I have a few other testings to do first.
 
I tried one of these a couple of years ago, and wasn't too impressed by it. What worried me the most about it was the wear and tear on the rotary buffer, as it seemed to be quite a bit off balance when I was using it and would be hard on the bearings inside the buffer. They may have changed it since. Would love to hear more people's reviews about this product.



John
 
JohnKleven said:
I tried one of these a couple of years ago, and wasn't too impressed by it. What worried me the most about it was the wear and tear on the rotary buffer, as it seemed to be quite a bit off balance when I was using it and would be hard on the bearings inside the buffer. They may have changed it since. Would love to hear more people's reviews about this product.



John
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One day soon you will be a believer in the power of random orbit. :grinno:
 
At the price these are being had for, I think we're going to get plenty of feedback from all sorts of users!



Personally, I have a lot of faith in its ability to cut paint. In my experience it does so incredibly fast. User comfort depends somewhat upon the type, size, and weight of pad being used, which is usually the case with any machine using an offset backing plate spindle.



As for polishing paint to the highest degree? Is it Do-able? I say, "Yes, do-able". Further, I say it's probably easier for the average guy to achieve their best result using this attachment paired with a rotary versus using just a rotary.



This unit was designed for use with large diameter pads. If the backing plate is changed to one that is dramatically lighter and then paired with a light weight buffing pad, I could see having some "comfort" issues.



Not only that, but if the diameter of both the backing plate and pad are changed to those featuring smaller diameters, I could envision a decrease in stability of the rotating components. Makes sense that a small diameter base on just about anything is going to be less stable if set in motion.



For both of these reasons, it would be wise to consider these points prior to exchanging of the backing plate and pads to those that are smaller in diameter. Not saying it can't be done... and not saying performance will suffer... just saying to be aware of the changes in dynamics.



Just sayin'. :dance



p.s.-

As for the long term effects on the drive machine, I hope to hear that it doesn't shorten bearing life. I doubt that it will when paired with the "sturdier" or heavy duty machines that have been designed to do double duty as grinders. This list would include machines such as the DeWalt DW849, the Makita 9227C, the Milwaukee 5460-6 and other units capable of being used as heavy duty grinders.



It would be great to test the effects on the smaller units. I suspect that if the bearing is high quality, and its support the shaft in a proper manner, there shouldn't be a notable failure rate, but I just don't have the experience say one way or the other with machines like the Metabo PE 12-175 or the Flex L 3403 VRG.



I'm speculating here... but I imagine that instability and dramatic weight adjustments could shorten bearing life more so than lugging about the extra weight. Perhaps the added weight taxes other components of the machine (electronic parts due to increased load) because it would take more juice to get the added mass up to speed.
 
Kevin,



It looks like the Dynabrade BP is about 6 3/4" - so I'm guesing 7.5" pads would be ideal? What do you think? And did you order one from them at 53 bucks?



I have a Dewalt coming for Christmas and thinking I might want another gadget too, I need something as smooth as possible!
 
dschia said:
Does anyone know the weight of this attachment?
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Yes.

The weight of the 61379 Dynabrade Dual Action Buffing Head is 653 grams, or 1.44 pounds without the backing plate.



The supplied backing plate weighs 144 grams, or 5.08 ounces. For comparison:



The Meguiar's W67DA weighs approximately 106 grams.

The Meguiar's W68DA weighs approximately 111 grams.

The Mirka 106GG weighs approximately 130 grams.

The Meguiar's S6BP weighs approximately 133 grams.



Some of the attachment's weight is attributed to three counterbalance weights.



The primary counterbalance weight weighs approximately 186 grams, or 6.56 ounces.

The disc shaped secondary counterbalance weight weighs approximately 45 grams, or 1.59 ounces.

The kidney bean-shaped secondary counterbalance weight weighs approximately 35 grams, or 1.23 ounces.



It looks like a lot of effort was put into the design of this piece to counteract the large offset and make it comfortable and stable to use with larger pads... kudos to Dynabrade for that!
 
JuneBug said:
Kevin,



It looks like the Dynabrade BP is about 6 3/4" - so I'm guesing 7.5" pads would be ideal? What do you think?
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Just measured the backing plate supplied with the 61379, part number 50855. It measures 6-7/8" edge to edge. If you were to cut the foam away, the remaining plastic measures 6" edge to edge.



This unit was designed to handle large pads- it comes with a pad measuring about 8" across.

Yes, 7.5" to 8" would be a great choice. Various literature lists that it was designed to handle 8" pads.



JuneBug said:
And did you order one from them at 53 bucks? I have a Dewalt coming for Christmas and thinking I might want another gadget too, I need something as smooth as possible!
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I did! Killer price, well below my cost if I purchased it through my auto body supply warehouse. Other than putting that dough towards an air compressor to blow buffing pads clean or towards the new D/A Microfiber Discs, this would be a great polishing investment.
 
Kevin Brown said:
Other than putting that dough towards an air compressor to blow buffing pads clean or towards the new D/A Microfiber Discs, this would be a great polishing investment.
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Kevin, I know you can't say much about 'em, but.... ;)



Do you think the DynaBrade will be a good choice for use with those new micro fiber DA pads?



I prefer smaller pads in general. I usually use 6" pads or smaller. See any issues with using smaller pads on the DynaBrade?
 
I'm bumping this thread back from the dead - cause with the new MF pads coming out, I'd like to know if this Dynabrade and the 6" MF pads would be a good idea or not.
 
I've been using my Dynabrade with the 6" Meguiar's MF pads for a while now, works great.



(I'll be replying to your PM shortly as well, Jimmy)
 
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