Meddings Overhaul – missing parts

[WoodlikesbikesParticipant @woodlikesbikes]

I’m about to start overhauling another Meddings drill. This one is missing a few parts that I’m not sure how to replace.

First up is the cover for the spring box. I’ve not been able to find an original anywhere. Does anyone know of a supplier? My next option is to modify a Branstons pickle jar lid. I reckon i might be able to cut slots in the sides in the hope that it pops in the same way as the original Meddings did. Does anyone have alternative suggestions?

I’m missing the knob from the switch. Given a NVR switch costs about £10 I’ll probably just fit that instead. But does anyone know where to find a rotary switch knob? The shaft measures about 4.6 mm so I’m guessing that it will need a 3/16″ one. But I’ve found nothing similar.

Finally, the are two nuts, one on the foot and one on the table clamp. They look crudely hacked to fit. I’m guessing these aren’t original. But I’ve found a picture online that suggests they might be. Can anyone clarify?

Many thanks in advance.

[larry phelan 1Participant @larryphelan1]

For what it,s worth, I “restored” an old bench drill [found in a hayshed ], which was missing the cover from the spring. I made one from a piece of tubing, using a piece of scrap plate to form the front, and just cut a few slots around the rim.  Nothing fancy, but it worked. Why not just replace the switch with a NVR unit from Aliexpress ?

[DC31kParticipant @dc31k]

The whole point of rstoring these classic machines is sympathy for their original looks. A modern NVR switch will look completely out of place.

For the switch knob, search for “chicken head knob”. They are used in audio applications (amplifier ones are larger than guitar ones, and would be closer to original). Avaiable from eBay and Ali. The square hole will not be correct, but you can make an adaptor bush.

The original switch is made by Santon amd knobs are interchangeable. You can keep an eye on eBay as you can pick up a complete switch and knob for £20.

I think I 3D modelled one, so a 3D printed one or using the 3D printed one to a cast one that looks close to Bakelite is an option.

What does the spring cover look like? Can you make a drawing of the important dimensions? To me, a jar lid will be too flimsy. You could make one from steel sheet, turning a flange on it in the same way you would do for a model copper boiler (but would need a steel former and heat). An outside option is a very large core plug from an engine.

[DiogenesParticipant @diogenes]

Pretty sure the nuts are original – threads in the castings wouldn’t last long.

I think the standard spring cover probably had grooves or some ‘grip’ to it so that there’s something to get hold of when tension is adjusted? ..an ali. casting? ..is there a groove round the body of  the spring housing?

[noel shelleyParticipant @noelshelley55608]

the square head bolt will be original. I would not bother with a £10 no volt switch, more likely to be trouble. Noel.

[DC31kParticipant @dc31k]

I did model one. It is parametric, so could be altered/scaled to suit any dimensions.

You know the shaft a/f and depth, so that is a start. Looking at pictures of existing ones and knowing the diameter of the aluminium backing plate will allow you to make a good estimate of the remaining dimensions.

That would allow a FDM print to be made as a prototype to verify proportions and a resin print (via one of the commerical 3D printers – JLCPCB or PCBway) final version.

 

[WoodlikesbikesParticipant @woodlikesbikes]

On the switch I’ll just fit a NVR. I much prefer the option of a big button to smash off than fiddling around for a switch in the event of an emergency. Plus I’m not doing a restoration. This is an overhaul and upgrade.

The original spring cover was made of a thin metal, probably slightly thinner than a jam jar lid. It pops open when you push the middle. It’s a neat way of keep the dirt out the spring. 

If I can’t get an original and modifying a Branstons lid doesn’t work. Then I might try a slightly larger lid with a magnet glued in the middle to attach to the spindle.

[DiogenesParticipant @diogenes]

.. ..”Practical Accountancy – Cost Saving Benefits in Manufacturing – Case Study 1″.. ..

[Michael GilliganParticipant @michaelgilligan61133]

Just on the off-chance, I had a look at Meddings’ ebay page:

https://www.ebay.co.uk/usr/meddings

… How the mighty are fallen !!

MichaelG.

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Ref. __ https://www.meddingsgroup.co.uk/machine-tools

[Howard LewisParticipant @howardlewis46836]

If they are still going, Bulgin made all sorts and sizes of control knobs.

If not, try and find a local amateur radio society. Someone there is almost certain to have a knob that will match the original.

Howard

[Woodlikesbikes]

On Woodlikesbikes Said:

The original spring cover was made of a thin metal, probably slightly thinner than a jam jar lid. It pops open when you push the middle. It’s a neat way of keep the dirt out the spring.

Here’s a rabbit-hole to explore:

https://www.qiminggroup.com/?portfolio=metal-lids-caps-covers

… I bet someone there would recognise the original Meddings item

MichaelG.

[BazyleParticipant @bazyle]

It would be an interesting exercise to beat a new spring cover out of sheet, maybe using copper if you want it more malleable. The switch will probably be common in the junk at radio rallies. Instead of defacing it with an NVR in the original position consider making a foot switch – much more convenient when what you need is both hands free to operate the drill and hold the work.
In 1980ish we had those switches as a general item in the stores at Marconi. I went down to HMS Belfast preserved WWII ship and the electronics had the same switch 40 years previously.

[Woodlikesbikes]

On Woodlikesbikes Said:

[…]  It pops open when you push the middle.[…]

 

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Variations on the theme:

https://fanxun.en.made-in-china.com/product/TJqroLXOHQkV/China-Japan-Finger-Press-Cap-for-Square-Engine-Oil-Can-B40-Metal-Cap.html?pv_id=1ik8t59coe8f&faw_id=1ik8t5mca73

MichaelG.

[Adrian R2Participant @adrianr2]

A Bach Rescue Pastilles tin has a thin metal pop on lid if you know anyone who likes them, just under 3″ diameter.

[Michael GilliganParticipant @michaelgilligan61133]

My guess is that Meddings simply used/adapted a conveniently available oil-can lid from the time.

The modern ones may, or may not, be the same size.

MichaelG.

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