Meddings MF 4/3 - removal of gearbox cover

[texutree]

I wondered if anyone could give me some advice on removing the gearbox cover on a 1978 Meddings MF 4/3. I purchased it recently knowing there may be ‘issues’ which may or may not be within my skillset to resolve. While the motor works, there’s no play in the quill and the table isn't too bad, the main problem I’ve got with this machine is failure of the high range gear to engage. I would like to get inside the gearbox to disassemble and replace any defective parts prior to reassembly, hopefully.

Having removed the pulley, circlips retaining bearings and all the M5 bolts around the perimeter, the gearbox cover doesn’t budge and there’s no play. Can anyone suggest how it can be removed?

Any information would be gratefully received.

 

[Pete.]

They often leak like a sieve so it may be just stuck down with gasket sealant. Your lack of top speed is probably due to a stripped plastic gear. Normally I offer to make them for people who need them but right now I don't have my machines with me as I've just moved house, but not the workshop just yet.

 

[zzr1200]

Normally I offer to make them for people who need them but right now I don't have my machines with me as I've just moved house, but not the workshop just yet.

Any idea as to when your workshop maybe up n running????

As I have a gear that needs making?

 

[texutree]

Many thanks Pete. Any idea what's the best way to loosen the gasket sealant? There is also what the parts list/diagram describes as a roll pin on the front right edge of the cover (to me it looks like a solid pin). I've not been able to get this out as there's only a couple of mm protruding to get some pliers onto

 

[Agroshield]

Any idea what's the best way to loosen the gasket sealant?

Drive a few stanley knife blades into the joint around its perimeter. Then slice between them with a snap-off type knife.

The roll pin probably does not need to come out. It wil remain in one half or the other when you separate the two pieces.

Failure to engage could be a problem with the selector mechanism rather than a stripped gear (on one I saw, the pin connecting the selector fork to the shaft had sheared), so don't lose hope just yet until you see inside the box.

The gear is available from Meddings, but is costly. If you have money but not time to wait, that might be an option.

 

[Brad93]

On the meddings, what you need to do is takeoff the two small covers which cover the bearings check that the oil is not varnished if it has then break it down with some brake cleaner I don't remember they're being circlets clips but if there are remove them unscrew all of the bolts for the cover and then there should be two holes which you screw bolts through to push the cover off of the actual gearbox bear in mind that the gearbox in these is a separate unit and not integral to the body of the drill

 

[texutree]

Many thanks for the advice above - I've managed to lift the cover by first separating it from the drill body by screwing two M5 bolts through the two smaller holes, pushing it up, as Brad93 said. Lifted it up by around 40mm and held it with some blocks of wood. but cannot figure out how to free things up any further as it all seems to be held in place by the selector lever (which it doesn't like like can be removed until the top plate is off). I must be missing something here. Anyway the high gear is definitely stripped as others had anticipated.

 

[Smouser]

@Pete. kindly made me and @Dieselman 63 a replacement gear for our drills.

I have attached a manual (not the best copy) which will hopefully help you.

I have also uploaded it to Vintage Machinery's publication reprints here.

 

[Smouser]

View attachment 461836

It looks to me like the 'shaft' the gears are on is just 'stuck' in the bearing which is in the top cover plate.

You should be able to separate it.

Btw, you have the newer version (square) of the Meddings MF4.

*Edit* there are now sellers on eBay selling replacement gears.

You can still buy a replacement gear from Meddings, just make sure you sit down when they give you the price.

 

[texutree]

Cheers Smouser, looks as I might have to buy a replacement from Meddings as Pete posted above he's not making them at the moment having moved house. I've yet to enquire what the Meddings price tag will be though!

Have tried tapping that shaft with a soft faced hammer to get it through the bearing, maybe I just need to use a bit more force on it

 

[Smouser]

Here is a better parts diagram of the square gearbox you have.

Looks like you need to remove a circlip or two.

 

[texutree]

Thanks - that diagram is much clearer than the one I have

 

[Brad93]

Many thanks for the advice above - I've managed to lift the cover by first separating it from the drill body by screwing two M5 bolts through the two smaller holes, pushing it up, as Brad93 said. Lifted it up by around 40mm and held it with some blocks of wood. but cannot figure out how to free things up any further as it all seems to be held in place by the selector lever (which it doesn't like like can be removed until the top plate is off). I must be missing something here. Anyway the high gear is definitely stripped as others had anticipated.

View attachment 461836

Thats newer than mine i'm afraid, mine had a separate gearbox.

 

[texutree]

It was a bit fiddly to do and took a little while but I was able to remove circlip numbered 227 on the diagram which sits underneath bearing labelled 243 on the input shaft and the cover lifted off together with the quill shaft & gears, leaving the input shaft behind.

Next job will be to remove the stripped gear (#239 on the diagram). I've removed the circlip and had a look with my bearing puller but I might take it to a local machinist to get the new gear fitted as even if I can get the bearing off (I only had a quick look but could only get 2 of the 3 feet under the bearing at the same time) I'm not going to be able to get it back on again without a press. I'll order a replacement gear from ebay (thanks for the pointer, Smouser) and take it from there.

Many thanks for the input and advice - I think I'm getting somewhere with it now! Hopefully I will be able to get it back together again without too much fuss when the time comes.

 

[Smouser]

Great stuff!

Don't be a stranger on the forum. Lots of clever people on here (me not included) who can give advice and help.

 

[texutree]

Just been trying to remove the drive shaft with tufnol gears from the gearbox cover. Have taken out the external circlips for the top bearing (numbered 230 in the diagram above) which is housed in the cover and was hoping I could then just remove the bearing together with the shaft - but the bearing remains tight inside the cover (pictured). Is the external surface of the bearing likely to be an interference fit here? All I can think to do is use some penetrating oil and put a small block of wood on the end of the shaft and try to gently tap it out with a hammer.

(The inner race of this bearing has noticeable play in it, allowing the shaft to wobble, so it will need replacing. I think it is 52mm OD on the 25mm shaft).

 

[Smouser]

I have not actually stripped a square type gearbox (only the older round ones) but I am sure the bearing is just 'pressed' into the housing.

You should be able to just knock it out (provided you made double sure there are no more circlips.

 

[500e]

#6 worth a read + heat on cover (paint gun)

 

[texutree]

Put the whole assembly in the freezer for a few hours, took it out and used a heat gun on the part of the gearbox cover around where it housed the bearing. Tapped the bearing (together with shaft) out easily. Thanks for the pointers and information!