Meddings M4 - welding repair

[Paul99]

After months of keeping an eye out I finally got my hands on an Old Drill press and I didn't have to drive half way across the country to get it - a Meddings M4 in pretty decent condition:

It's been well looked after on the whole only a few shallow marks in the table:

All the bits are there (bar for the chuck key) and came with a brand new spare reversible motor (current one isn't wired for reverse) also came with a bucket of drill bits too

The one slight issue is where the backbone sits into the cast lower leg - someone's obviously over tightened the clamp and cracked one leg of the bracket off. A very poor attempt has been made to weld it (there's more slag inclusions than weld ) which failed with just a slight bit of pressure when I re-assembled it - the top half of the drill can pivot under a bit of pressure:

In reality it won't affect the function but I'm wondering whether to have another go at repairing as it can't really make it any worse. I've not ever attempted welding cast iron before so what would be your advice - will Mapp gas get it hot enough for pre heating or should I take it to a mate's garage to get the oxy acetylene on it? and what cast rods would you recommend - or should I look at getting it brazed instead?

your advice is welcome...
Paul

 

[Paul.]

Don't bother pre heating, to do it effectively and evenly you will need an oven to take it up to around 500 deg C, use a nickel rod and weld it reasonably cool, use short runs about an inch or so, and lightly peen the weld between runs.
Make sure to get all the old scabby weld out before you start, and prepare it by grinding a vee into the joint.

 

[Paul99]

Don't bother pre heating, to do it effectively and evenly you will need an oven to take it up to around 500 deg C, use a nickel rod and weld it reasonably cool, use short runs about an inch or so, and lightly peen the weld between runs.
Make sure to get all the old scabby weld out before you start, and prepare it by grinding a vee into the joint.

My brothers commercial oven wouldn't get that hot even if I could fit it in - it's bigger than it looks in the photo. It sounds like it'll be a leave it and live with it job for now then. I may well just see how much trouble it will actually cause in use - my initial thoughts are that it'll never be a problem anyway but if it is then I may drill and pin it with a brass rod so it can easily be removed if needed in the future.

 

[Paul.]

Its a simple repair, the nickel electrodes take a bit of getting used to if you have never used them, and are best used on DC, the difficult bit would be finding someone who will sell a few loose ones, a pack will cost more than the drill is worth,
You would need to lay the drill on its side to get the weld in the flat position, they are not easy to use in position.

 

[Paul99]

Its a simple repair, the nickel electrodes take a bit of getting used to if you have never used them, and are best used on DC, the difficult bit would be finding someone who will sell a few loose ones, a pack will cost more than the drill is worth,
You would need to lay the drill on its side to get the weld in the flat position, they are not easy to use in position.

Thanks Paul, I have an arc inverter and I see you can buy small quantities of nickel electrodes on eBay (not sure if they are any good though) Laying it flat is simple too it's remarkably easy to dismantle it all - two people needed to lift the head off and then 5 bolts and it's broken right down - certainly easier than trying to tip the whole thing over my god it's heavy...

 

[BillJ]

Our local agricultural supplier sells them singly. I'd be surprised if there wasn't something similar somewhere in mid-Wales.

 

[@Turbo]

I used nickel rods before to weld a table on a re saw. it cracked like mad when it was cooling but it still held. Think I let it get too hot so just be wary of that.

 

[Paul99]

Thanks all, I've watched a few you tube demonstrations of nickel rods and from what I saw and given the advice here (pretty much the same thing really) I think I could manage a repair. There are quite a few agricultural repair places locally I'll try first for rods if not I'll spend more time looking online.

I've got half a dozen different cast jobs that have built up over the last few years that I've stored away for "one day" as I always considered it to be a near impossible task that's rarely successful - I remember well those very words coming from the design and technology teacher at school - he was no welder though so guess he was wrong.

When I eventually get onto the job I'll be sure to update the thread with the results...

 

[brightspark]

Thanks all, I've watched a few you tube demonstrations of nickel rods and from what I saw and given the advice here (pretty much the same thing really) I think I could manage a repair. There are quite a few agricultural repair places locally I'll try first for rods if not I'll spend more time looking online.

I've got half a dozen different cast jobs that have built up over the last few years that I've stored away for "one day" as I always considered it to be a near impossible task that's rarely successful - I remember well those very words coming from the design and technology teacher at school - he was no welder though so guess he was wrong.

When I eventually get onto the job I'll be sure to update the thread with the results...

why dont u practice on some old cast iron 1st thats of no importance

 

[Paul99]

why dont u practice on some old cast iron 1st thats of no importance

Yep I certainly will do, though with the price of the rods, I'll make sure not to get too carried away.

 

[arceyered]

I would Fabricate a replacement part out of steel and bolt to base plate, put a grease nipple and grooves in as there is no free carbon.

 

[Hopefuldave]

Can't see how you'd be able, on steel replacement - part of the column base, innit? I'd braze or weld the lug back on, if there's a way to I'd fit a split cotter rather than relying on the clamp.

Before anyone asks, split cotter = two tubes, one threaded for clamp bolt, with a cut away radius that bears on the shaft (round column in this case) as you tighten the bolt and pull the two together. As it's 'floating' it shouldnt break the collar unless some gorilla really swings on the wrench....

 

[Paul99]

I managed to track down a few pure nickel rods for this fix - they've been sat on the shelf for quite a while. I've had manflu for a few weeks though and whilst feeling weak the thought of having to lift the head back off has so far put me off doing it. I have been using the drill in the meantime though and as suspected I could quite easily leave it as is and it'll never be a problem. - not unless I ever come across a job where I need to clamp to the base rather than the table - which is highly unlikely. Will see what the weekend brings...