high speed bearings

[muddstopper]

I am in need of flange or pillowblock type bearings, for a 7/8in shaft, that are capable of withstanding 6000-8000 rpms. I have been searching for spec's for the popular surpluscenter, tractor supply, northerntool varities and can seem to find a speed rating to go with the bearings they sell. I think the standard bearing is only rated to about 3500rpms, but havent been able to verify that. The shaft will be supported by 2 bearings on either end and wont be over approx 16inches in lenght. There will be a double V pully of 2.55inch dia on one end and a 13tooth .404 saw chain sprocket on the other end. I will be applying approx 20-25hp of hydraulic power to spin the shaft. I need to know if there is a specialty bearing I can buy that will meet my requirements, as well as where I might purchase it. Any help would be appreciated.

 

[BHD]

my guess is you will need some type of oil pressure feed bearing,

motor cycle and chain saws use needle roller bearings that are at lest splash lubricated, on there shafts and connecting rods,

http://www.grainger.com/Grainger/ne...nsmission/ecatalog/N-bo4?op=search&sst=subset

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http://www.timken.com/pt-br/product...ngs-for-Machine-Tool-Applications-Catalog.pdf

check put pages 51, 112,138, 142. they talk about high speed bearings, many say contact the company,

the other Idea is to order some machine tool bearings say for a commercial heavy duty router, (not a home shop router but a industrial router), or find a similar process and adapt the bearings or idea to your project.

I think you need to contact a bearing supply house, and not farm stores,

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another catalog,
main menu
http://www.nachi.de/files/Bear.pdf
hi speed bearings
http://www.nachi.de/files/Bear.pdf

 

[RBA50]

McMaster Carr will let you search for bearings by speed rating. They have several types with ratings that match your requirements

 

[muddstopper]

I think you need to contact a bearing supply house, and not farm stores,

Actually I did contact a company, Impact Bearing :: Your Bearing Solutions , but they havent called me back. I hadnt thought about Mcmaster Carr, I will look them up now. Thanks.

 

[BHD]

I think the standard bearing is only rated to about 3500rpms, but haven't been able to verify that. .

I had found a place last night and that is a true statement , some are less than that in the 2000 range,
this is for a lubricant, but still has the RPM limit calculator, MicroPoly Lubricants :: Maximum RPM Calculator
click on there high speed tab, some info on a special high speed lub,

here is a search for bearing maximum rpm might be some thing there you can glean, bearing maximum rpm - Google Search

I think the trick it the lubricant and the precision of the bearing and it ability to dissipate the heat, of course the size has a big factor as well, but your not in to large here,
many like a motor cycle engine uses the lubricant to take the heat away, and to resupply the lubricant, a sealed bearing is tougher,

 

[Redneck in training]

I am in need of flange or pillowblock type bearings, for a 7/8in shaft, that are capable of withstanding 6000-8000 rpms. I have been searching for spec's for the popular surpluscenter, tractor supply, northerntool varities and can seem to find a speed rating to go with the bearings they sell. I think the standard bearing is only rated to about 3500rpms, but havent been able to verify that. The shaft will be supported by 2 bearings on either end and wont be over approx 16inches in lenght. There will be a double V pully of 2.55inch dia on one end and a 13tooth .404 saw chain sprocket on the other end. I will be applying approx 20-25hp of hydraulic power to spin the shaft. I need to know if there is a specialty bearing I can buy that will meet my requirements, as well as where I might purchase it. Any help would be appreciated.

Two cycle engines like in motorcycles have high speed bearing. Motorcycle dealers could have them in the diameter you need but you will need the housing.

 

[BHD]

for a 7/8in shaft, that are capable of withstanding 6000-8000 rpms. The shaft will be supported by 2 bearings on either end and wont be over approx 16inches in lenght. There will be a double V pully of 2.55inch dia on one end and a 13tooth .404 saw chain sprocket on the other end. I will be applying approx 20-25hp of hydraulic power to spin the shaft.

I jsut tryed to find what your looking for, at first now I am trying to talk you in to cahnging your desigine,

one go with a larger sprocket, if you need that kind of feet per min, on the chain,

but for an example (my guess is you reverse enginer most wood processers, you will find the chain moving much slower than a chain saw,

and for example out power company show up one time with a pole chain saw for triming limbs and a hand held hydralic that worked off the trucks hydralic system, and I was waching them, and notireced the chain was slow in comparison to the gas saw I have, yet it was cutting as fast and they said it hardly ever dulls, (my guess is the deth gages were ground down for more bit,

but I would study out the prcessers and the mechincal tree machines that use that size of chain, and see what they are using for rpms,

you take that kind of speed and HP, and your workign your bearings

http://www.tractorbynet.com/forums/...emade-firewood-processor-hydraulic-chain.html

Standard Hydraulic Chain Saws & Components

404 Grapple Saw

Chain Saw Sprockets

 

[cycle_gator]

What are you building that needs such a high RPM range with a 7/8 shaft and transmitting only 30 hp?

 

[muddstopper]

What are you building that needs such a high RPM range with a 7/8 shaft and transmitting only 30 hp?

Gator this link 404 Grapple Saw by BHD is exactly what I am building, except instead of a grapple saw, I will be using it on a firewood processor.

BDH, I have looked at just about every manufacturer of this product and have researched the saw and motor requirements pretty extentsively. The Danzo saw uses a F11 radial axle type of hydraulic motor and they are pretty pricey. The advantage of this type of motor is high speed and high torque. I have looked pretty hard for a used one and havent been able to find one I was willing to pay for. What I do have on hand is a Rexroth highspeed motor capable of 3150rpms at 2300psi and 18.5gpm. In talking to the company I am purchaseing the bar and chain from, they claim I wont be very happy with the slow speed of my motor and suggested a minimum speed of 4500rpms. While researching chain speed I looked at some of the bigger chainsaws, the large husqvarnia, 3120xp. This saw uses the .404 size chain, its maximum speed is 9000rpms at 8.4hp with a chain speed of over 65 fts . What I am trying to match is the speed and power of the 3120 saw with the parts I have on hand. Using the 13tooth sprocket will put my chain speed right at the 65fts mark of the production saw. Using a belt driven jackshaft and mounting the sprocket will allow me to double the speed of my motor, while reduceing the hp that drives the chain. I will still be overpowered according to the spec requirement of the husqvarnia 3120, but that just means I dont have to run at WOT while doing the sawing.

You also mentioned using a larger sprocket on the motor, yes you can do that, but it does have its drawbacks as well. The larger the dia of the sprocket, the larger the width of the bar that is needed. Looking at a chainsaw bar, you will notice that the bar is tapered down in width near the sprocket. This is necessary to keep the chain on the bar and in direct contact with the sprocket at the same time. Not a problem on a new chain, but as the chain stretches, the bar gets farther away from the sprocket, when this happens, more force is put on the back of the bar which creates heat and wear problems on the bar. The manufacturer I was working with suggested that I stay away from the larger sprockets and fatter bars. I figure since he could have sold me either, he has other reasons besides wear problems for makeing the suggestion of staying with the skinnier bars and smaller sprockets.

 

[CalG]

Pick a smaller shaft size

Routers routinely spin 15k rpm on greased double sealed ball roller bearings. Two stroke crank bearings can do the same on oil mist.

A 6203 double sealed from a name brand mfg. would carry the load at speed for many many hours.

 

[Cpjlube]

I think the idea of building my own processor is cool. Never really considered having to include a bearing capable of 9000 rpms. I would hate to be near it, if it failed. I would design a hefty shield for that shaft. Make sure to post som pictures as you build.

Chuck

 

[muddstopper]

When chooseing shaft size, one also must consider side load, torque and twist. While a router motor might spin 15k rpms, it doesnt have 25hp twisting it into a prezel either.

Most of the processors you will see will have the sprocket mounted on the end of the hyd motor, not on a jackshaft. Most the the factory processor also have very slow cutting saws. This is because they use cheaper gear motors to try and keep the cost down, F11 motors are pretty pricey, and they also use small hp engines barely capable of powering the machine. What I have noticed on most, if not all the smaller commercial/homeowner processors is that there are two potential choke points when it comes to high production. One, the splitter cylinder is to slow and they endup waiting on the cyl to retract before they can cut another block of wood. Two, the saw cuts to slow, so they still endup waiting on the saw. Circle saw processors on the other hand cut faster, use larger engines, and are a lot more expensive to purchase. I am building a chainsaw type processor because its simply cheaper to build than a circlesaw processor.

 

[Brad_Blazer]

Mcmaster has it for $102
McMaster-Carr

If you can make your own mounts you can use $10 bearings.

 

[90cummins]

The operating speed of a bearing also dictates the method of lubrication.
Grease is used on slow speed bearings and light oil or oil mist is used on high speed large bearings.
You have a difficult application.
Is a continuous operation at speed or momentary?

 

[muddstopper]

Mcmastercar has one I think will work for about $46, but I need to research it a bit more. I am still waiting for ImpactBearings to call me back. I dont always trust what I read in catalogs, mostly because I dont always understand the terminology. I prefer to talk to a expert for things I aint sure about.

As for the quetion of continuous speed, no, the saw design will be so that when the saw isnt actually cutting, it will be stopped. Lots of starting and stopping. I will be using a electric over hydraulic control valve to control the hydraulics for the saw. It will only be energized by use of a micro switch, attached to the manual control valve being used to extend the cylinder for lifting and lowering the bar and cutting the log. As soon as the cut is complete and the bar is raised, the saw motor will stop running. The control valve will be self centering so that continous pressure on the hand lever is required to keep the electric circuit complete for saw operation. As soon as I let off the control lever, or raise the saw bar, the chain should stop running. I cant see myself, or anybody else letting the chain run in the upright position. As another safety precausion, I also intend to use a electric limit switch at the log clamp inline with the electric circuit for the saw. I want the log clamped tightly before the saw starts to run. I have seen handheld chainsaws kick pretty large pieces of wood if the chain hangs even a little bit, I dont need that to happen with a log that might be near head height while in the feed conveyor.

 

[Hooked_on_HP]

Are you going to have enough hydraulic flow to operate this type of hyd. motor.
Bill

 

[muddstopper]

The processor will have three pumps, one for the saw, a 28gpm 2stage for the splitter, and a 4gpm to operate the conveyor, log clamp and sawbar. It takes 18.5gpm @2300 to run my hydraulic motor 3150 rpms. I will be powering it with a 58hp diesel engine. The saw motor will require 29hp and the splitter pump 16hp so I should have the necessary hp and flow needed to run both the saw and splitter at the same time with about 10-18hp in reserve. The conveyor to feed the logs only runs intermittely and will only run when the saw isnt running so I havent factored it into my hp requirements.