Hammer mills are like flail mowers the good ones are bought out and put out of business at least in the Mott flail mower case anyway.

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Greetings and salutations Redtrey from my corner of the very soggy eastern wilderness @ 1140 feet above mean sea level.

The bearings are the deciding factor in your question;

The motor pulleys, flywheel pulleys and V belts also figure in the mix.

In your case will you be changing the motor pulley only and installing new matched belts?

You need to find out the type of bearings you have and their recommeded speed.

meaning are they

bronze babbit

single roller

double roller

barrel roller

double barrel roller

tapered barrel roller

double tapered barrel roller

Most likely they are at the top of their collective rpm range but that is an unknown as of today.

also the bearings are either a slip fit or a press fit-press fit being more difficult to work with.

A lot of high speed bearings are oil lubricated these days also

FYI if you can simply remove a bearing end cover for both hammer mills-

the bearing depending upon whether it has the cup or cone exposed hopefully the cup to the outside-

The bearing identification numbers will be stamped into the wide edge of the cup or cone race.

The identification will give you all the information required to identify the bearing and its maximum speed rating.

The other question is are hammer arms and anvil still available or do you do the resurfacing your self?

If I can help in any way,

leon ■

First rule never assume anything- borrow or buy an contact tachometer or borrow or buy a non contact tachometer a good hobby shop will have one in stock for sale.

I would contact a local bearing supplier or a bearing representative and chat about this over a pint or two with what material you have

as far as the machinery manuals, electric motor specs current actual speeds deterimined from a contact or lazer tachometer for all parts-

1. electric motor plate ratings.

2. both belt pulley sizes for both hammermills

3. flywheel sizes, flywheel anchorages- keyed and set screwed, locking ring for high rpm, or taper lock for low rpm

4 The bearing mounting shaft outside diameter of both hammermill rotors.

a. outer bore diameter of bearing housing- this is going to tell you if you can replace the bearings in use assuming you will be able to use-a tapered barrel roller or a double tapered barrel roller bearing set.

nasty factor two may be the need to change the type of lubrication from grease to oils-can be done, been done etc.

5. belt sizes- you will end up changing the belts for heavier belts most likely-V belts must be of the same lot number !!!!!!!!!!!!!!!!!! when replacing belt for belt

the Hammermill RPM is a function of the electric motor speed which in turn rotates the driven pulley and or flywheel or both in your case at a slower speed.

all that has to be taken into account with a lot of basic math to determine actual and desired speeds

dont forget the hammer mill shaft is rotating faster than the pulley, flywheel etc., or the orbit speed of the hammers!!!!!!!!!!!!!!

until you know the rpm rating of the bearings etc.,etc.,etc.

A more robust bearing set will have a heavier cup and cone if a tapered roller bearing or a heavier roller set and inner race.

You should think about this for a while as you may end up slowing the feed rate of the limestone due to plugging and tripping out the electric motor at a faster delvery rate.

perhaps upgrading to a vertical impactor such as the smallest spokane crusher could replace both units with a recirculation circuit- but if you are happy with how everything runs etc. ■

Originally Posted by redtrev

I have a variable speed drive controlling the No.4 mill so eay enough to find out exact speed on that one.

The two mills although operating side by side and of the same plant are used for different products, i.e different production lines so replacing with one crusher wouldn't work besides both mills work excellently.

I will check with bearing manufactures and take it from there.

Cheers for help mate.

Trev.

Greetings,

You are most welcome, please keep us in the loop with your progress;

The B10 life-at higher rpm will be the overriding factor in any decision as far as the bearings so please keep that in mind; maintaining the new inventory of bearing spares for the mills is the other expense-unless you have ready access to a bearing warehouse nearby during operating hours. ■

Originally Posted by redtrev

Hi All,

I talked with my bearing supplier over the weekend and he feels that the existing bearings are well able to for faster shaft speeds than the maximum rated for the crusher - 1500rpms

He feels that 1500rpms is low for crusher bearings and that 1800rpms should be no problem for the existing bearings.

Though this might be of interest to some.

Regards,

Trevor.

Be very sure to add spring pressure grease cups to each bearing trevor as this guarantees grease to the bearings. ■

Originally Posted by redtrev

Lzaharis,

Could you elaberate a little on these spring pressure grease cups, as i ve never heard of them. Mind you im no bearing expert.

Trev

The spring pressure grease cups are great way to deliver grease to bearings with no fuss.

The McMaster Carr catalog will have them in their master catalog on the web.

The grease cups must be installed vertically/upright to meter grease properly.

No wasted grease or excess grease dripping on the floor either. ■