Warco GH Major Milling Machine

Hi all,

Never rains but it pours!! The gearbox on my mill GH Major Mill has started making what sounds like 'metal on metal' noises. When conventional milling it comes and goes when climb milling it is almost constant but not regular - if that makes sense.

It originally sounded like coming from the motor spindle drive. I removed the motor and found that the keyway in the gearbox drive shaft was badly worn and that the 6mm key was loose in the motor shaft keyway. Probably was never a good fit from production

I got the files out and made a new key which is a good snug fit in/on both shafts so I know the there is no 'slop' between the motor output and gearbox input shafts. So, sorted I thought but it is not. On starting up the mill is quiet. But when under load it makes the noise again.

I have found that the there appears to be a lot of backlash in the drive chain between spindle and motor. I have close to 90degs. rotation of the spindle before the motor moves,

I would like to ask those of you with this mill to test the amount of backlash you have and let me know. In speed H1 please.

Has anyone attempted to strip and rebuild one of these gearboxes? If so would you prepared to share you exprience with me?

Best regards

Deric

Deric Hi,

I’m surprised that no one has answered yet as these are popular machines but perhaps you have had a private message with the information already. Hope I am not trying to teach granny. I expect you have already but, I have always found a phone call to Warco to talk with one of their engineers useful. They have always been helpful and know the machines they sell well.

I have just had a look at my unused Super Major and there is virtually no free movement as you describe, perhaps 10-15degs at the very most. Your machine is what is known as an RF40 clone and sold under many names and slightly different specs. The head is very similar to the larger RF45 which is a very popular conversion to CNC and a Google search for RF45 gearbox will find a number of sites that cover a gearbox re-build and repair. They do on occasion have gearbox bearing problems.

Is the backlash consistent? If you rotate the spindle a few turns to put the gears in a different position does it stay the same? Is it the same if you select a different gear ration? This will give you some clues to decide which shaft/gear cluster is to blame; unfortunately in either case a gearbox strip is needed.

You will find a good set of pictures of the similar RF45 gearbox here:

**LINK**

**LINK**

There is also a Yahoo group that covers Mill Drills that include the RF40 clones. They have a good PDF file in their file section that covers a gearbox strip and re-build. If you don’t want to register and download I can send you a copy if you let me have your email address.

I haven’t stripped one of these myself but they look fairly straightforward and the bearings are available from most bearing suppliers.

Hope this helps a little

Keith