My Wits End

Well you don't mention any details... ie: shaft size, part nos, price paid, grinder type and model........found this though

https://www.arboristsite.com/community/threads/vermeer-630a-pillow-block-bearing.205817/

Thanks for the link. I will happily pay $125 per bearing compared to the wild quotes I've received $303 - $356 here in rip off U.K.

PB22423H 1-7/16" bore. I will happily pay $125 compared to the rip off range of prices I received ($303 - $356)

Specifications and pictures are often helpful, especially for the "off the wall" suggestions. Someone might come up with a suggestion for a standard bearing (lower cost wear item) and a custom gadget for adjustment (one-time acquisition, low wear).

SKF and others do double taper bearings that you can tighten to take up slack.

Not cheap but there again I don’t know what you’re using now.

As explained in my initial posting I need an equivalent bearing that offers a wear compensation adjustment as does Rexnord-Link Belt but at a lesser price. Here in rip off U.K. I am getting quotes ranging in price $303 -$356+ (£233 - £276+) for PB22423H Rexnord bearings. They seem to have their market sewn up.

Contact the person at this link and describe your particular needs.They do offer their bearings in standard inch sizes. Perhaps this guy can help you.----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sorry I cannot post a proper link,just cut and paste. https://www.igus.co.uk/myigus/default.aspx?page=form_contact&adre=464

Look for replacement substitute from Timkin Bearings. They are a world leader in all types of bearing,including mining,conveyors,etc.

A bearing number will be VERY HELPFUL.

For reference: Spherical Plain Bearings or Stay with Spherical Rollers from last year.

Hmmm, maybe you just need a bigger grinder....?

Its somewhat difficult getting these into back yards!

I saw an article about this recently referring to IGUS replacements. See www.igus.co.uk/igubal

"Motion plastics specialist igus introduces igubal spherical balls that can be inserted into existing metallic pillow block and flange bearing housings within a few seconds. These bearings, which are often used in construction machines and conveyor systems, are exposed to harsh environments requiring regular lubrication and maintenance. The igubal spherical balls are injection moulded in the high-performance plastic iglidur J, which is self-lubricating. The retrofitted bearings therefore are maintenance-free. Another advantage is that due to the absence of lubricant, dirt and impurities can no longer adhere to the bearings. Thus, there is no long downtime of the machines and plant for maintenance.

The long service life of the igubal spherical balls has already been proven in a biomass chipper. The original metal bearings on the conveyor belt of the machine had to be lubricated each month. When the flange bearings were retrofitted with igubal spherical balls, the bearings remained wear-free for more than a year, without the need for lubrication and maintenance."

Thanks for the great link.I am always interested in new technology.I have seen dry UHMW bearings in dirty,abrasive and harsh chemical environments out last many lubricated bearings in same application. The IGUS bearings appear to be a combination of UHMW,or similar polymer,plus nano-embedded coating,and embedded lubricant.Forest mulchers are very high maintenance because of the harsh environment and high wear of all components.Most skid steer mulchers are sold for parts at around 3000 working hours,or need a complete overhaul. The low clearance requirement helps to exclude dirt, and any dirt that does enter is embedded into the base coat and does very little damage to shaft. When dirt enters a grease lubricated bearing,it mingles with the grease and grinds away at the rollers and races,like a grinding compound. I will try the IGUS bearing myself when the need arises.

Sounds like a great bearing for conveyors, but as previously explained for a stump grinders cutter wheel that is subjected to intense grit, vibration, and shock loading, I have my doubts as to its suitability.

Unfortunately, these Igus bearings max out at 30mm and are not offered in imperial sizes. I am running 1-7/16" shafts and to convert over to metric is cost prohibitive.

I use Rexnord - Link Belt PB22423H pillow blocks. Below is the response to my question about Timkin I received from a UK supplier.:

Clive Simkins <clive.simkins@acorn-ind.co.uk>

08:57 (2 hours ago)

Reply

Hi Mike,

"Just to clarify the differences between the Rexnord Housed unit and Timken alternative.

Although the Timken unit has the facility to adjust the bearing from a ‘fixed/located’ to a ‘free/unlocated’ it does not have the same facility of the Rexnord unit of altering the bearing seating owing to wear.

The only comment on this would be that depending on the amount of wear would question for how long the bearing could operate successfully afterwards.

With regard to the base to centre of shaft measurement comparisons:

Rexnord – 47.625mm

Timken – 47.8mm"

Regarding Clive's comment, "would question for how long the bearing could operate successfully afterwards." --- is just a smoke screen to put some doubt in my mind so he can sell me Timkin when to my experience Rexnord's wear compensatory adjuster has more than doubled the service life. In fact I disassembled a bearing to inspect the rollers and races for fretting, brinelling, etc. after having run out of any further wear adjustment, and found nothing apart from obvious wear.

If Rexnord has indeed cornered the market with this particular wear compensation feature I will pay their price, but just put out the question is their an alternative with this feature.

Have you given any thought to making up a pair of housings that would accept back to back automotive tapered roller bearings? Load is high, adjustment excellent and wheel bearings are generally dirt cheap.

Maybe you should just soften up the stumps a little before grinding...

Project Gutenberg has a book available from Dynamite Nobel entitled "Farming with Dynamite" that includes such procedures not only for removing stumps, but also for high speed hole creation to plant new trees.

I think the key is to drill in the ground beneath the stump....seems more effective at taking a deep bite....

How to remove big whales....

Here is a link to a Rexnord surplus page. Maybe this will help. gonna have to cut and paste. ====================================================================================================================================================================================================================================================================https://hebeama.com/p-b22423h===============================

I dug a little deeper on the Igus bearings and they are not suitable for your application,the shaft speed is too high. I am wondering if the bearing wear you are experiencing is due to dirt entry into the bearing. Are the Rexnord bearing seals triple -lip seals?I think you need a shieldedand sealed bearing. I do not know if this is applicable,but there are Bearing Buddies available for boat trailers.They provide a constant supply of grease to a bearing under a slight pressure..not enough pressure to damage the seal,but enough to keep out external contaminants.You may be able to find a suitable size for your application. At a bearing seminar,many years ago,provided by Fafnir Bearings ,we were told that the number one cause of bearing failure is Over greasing. More than dirt!It was very hard to believe,but it was explained. According to them,over greasing of a bearing will not allow the grease to get out of the way,and it will churn the grease,causing a heat buildup which will turn the grease into carbon,which in this condition, is hard and has no lubrication properties.Bearing failure will result. Too much grease can also cause seal failure and allow contaminants into the grease. I know if you own the equipment,you take very good care of it,but greasing can be overdone. I have still got my feelers out for a replacement for the Rexnord,so don't give up just yet.

Here is a link for substitute replacement bearings:======================================================================================================================================================= https://www.thebigbearingstore.com/1-7-16-m2000-heavy-duty-two-bolt-pillow-block-bearing/ Good luck!

... And just how did this Mechanical Engineering question come to be posted in the Civil Engineering Section ?...

Stumps is wood.

Stump grinders turns them into chips.

Chips can be made into OSB.

OSB can be used to make buildings or crate up exploded whales.

That makes it civilized engineering.

Wooden stumps consist of wood cells...

Check with these people in the following link regarding rebuilt bearings.They can rebuild cost for about 60% of the cost of a new one,and they are as good as new.

Do you have any old used bearings to send to them?

http://scheererbearing.com/uploads/pdfs/Scheerer_Bearing_Rebuild_Recondition.pdf