How to Choose the Correct Bonnet Size

[encapman]

Sometimes there's  confusion about which bonnet size to choose. Here's a brief overview on bonnet sizing as it relates to rotary and orbital machines. Also a breakdown of pad driver sizing as it relates to the machine size.



Pad drivers generally run 2 inches smaller than the deck size of the machine. That means if you have a 17" machine, you'll actually have a 15" pad driver. If you have a 19" machine, you'll actually have a 17" pad driver.

With any machine, you'll ALWAYS want to have some overlap with the bonnets - beyond the edge of the pad driver. For example, if you have a 17" rotary machine, at the very minimum, you'd want to have a 17" bonnet. Keep in mind, the 17" machine actually has a 15" pad driver, so with a 17" bonnet you'd be adding an additional inch (1 inch) of bonnet around the perimeter of the driver.

Now let's bring this into perspective with an orbital machine. Orbital machines are highly jiggly as you know. So it becomes even more important to run the bonnets on the large-ish side. In the case of an orbital machine it's recommended to go 2 inches larger than the deck size of the machine. In other words, if the deck size is 19", then ideally you'd want to go with a 21" bonnet.

In the case of a 19" orbital machine you're actually running a 17" pad driver. Therefore you'd need a 19" bonnet at the very minimum to sufficiently cover the driver. Recall that a 19" bonnet will add an additional inch (1 inch) of bonnet around the perimeter of the pad driver. But an extra inch doesn't amount to very much wiggle room on an orbital machine. So with a 19" orbital machine, you'd really want to consider going with a 21" bonnet. And with a 17" orbital machine you'd likewise want to increase 2 inches and go with a 19" bonnet.

Bottom line rule of thumb: For a rotary machine, select a bonnet that equals the deck size of the machine (actually 2 inches larger than the pad driver dimension). For an orbital machine, select a bonnet that's 2 inches larger than the deck size of the machine (actually 4 inches larger than the pad driver dimension).

Selecting the correct bonnet size will improve the performance of the machine (especially in the case of orbital machines). And you'll enjoy working with the machine much more!

[lancer1004]

for 17 inch rotary machine 175, what size is better? 17inch or 19inch?

[encapman]

Either size would work. 
A 17" bonnet will be very satisfactory. 

Copied from above... "For example, if you have a 17" rotary machine, at the very minimum, you'd want to have a 17" bonnet. Keep in mind, the 17" machine actually has a 15" pad driver, so with a 17" bonnet you'd be adding an additional inch (1 inch) of bonnet around the perimeter of the driver."

A 17" bonnet for your rotary machine will do the trick. 

[joeyjcc]

Don't tell my wife..... I'm in love with the 21" Bonnet size!
Just used a 21"Microbeast-2 today on my Lowboy machine. What a pleasure. The bonnet didn't buckle underneath and the extra few inches got right up to the edges. I 'ain't' never going back!

[encapman]

21" is the PERFECT size for the Vario.

An orbital with a 17" driver benefits from having a couple extra inches of additional bonnet space around the perimeter. In other words, a 21" bonnet is 4" larger than the driver, which actually provides 2" surplus on all sides of a 17" driver. That gives you the extra "wiggle room" that you need.

[encapman]

And as you noticed Joey, the newer style bonnets that we had spec'd are very firm which is really helpful! We had the bonnets designed with increased rigidity to help them not fold up under the machine. We loved the firmness, but it turned out that they weren't quite as durable as we wanted. So we're now clearance pricing all those old bonnets at a loss. I'd rather take a loss on these bonnets since the material wasn't as bulletproof as we expected.

Good news though! We've now moved our bonnet production to a new microfiber bonnet manufacturer. We have spec'd out a very nice bonnet! We've received samples of the new bonnet and it tested very well! The new bonnets are very firm, and they're more durable. The new version will be called Microbeast Pro. It's been a search to find these bonnets and have them developed the way we want, but we're happy that we now have some very nice bonnets in the pipeline. We should be receiving the new Microbeast bonnets in the next couple of months (they're currently going into production). Stay tuned