At last I'm starting to do jobs I want to do rather than jobs I have to do. A few years ago Bron kindly bought me a Clarke CL300M metal turning lathe as a Christmas prezzie. I had sold my big Colchester so wanted a small lathe until I bought another lathe to replace the Colchester which was too big for the garage it taking up a big footprint.
I'm used to big machinery so first job was to destroy the circuit board and motor on this Clarke both expiring in a cloud of smoke much to my dismay. I had been putting a light cut of 60 thou on when it expired having not read the manual. Now when I read the manual it states do not exceed 10 thou cuts? 60 thou to me whilst using the big Colchester was merely scratching metal and I thought I'd have no trouble with such a small cut on the Clarke but it was an expensive lesson to learn.
No way was I going to spend over £100 for a flimsy circuit board and I hadn't a clue what the tiny motor would cost and couldn't care less if this was the performance to expect? To cut a long story short I bought a brand new industrial sewing machine servo motor which too was variable speed. I grafted this much larger motor on but had to do this by designing and installing a countershaft into the original tiny motor housing; it was a squeeze but I did it.
The servo motor is lever operated for start/stopping the lever returning to off by a powerful spring so obviously some kind of linkage would be needed but at the time I was bogged down with more pressing jobs so came up with a very high tech solution by cutting a block of wood just long enough to wedge between lever and chip guard and I got very used to popping this block of wood in but it always bugged me. Having finally caught up I've been giving this problem a lot of thought and it proved a lot more difficult to resolve than ever I expected in fact I had a couple of attempts without success.
This morning I wandered into the garage after pulling the car out to give the car another soaking and really set about this problem. I measured the end of the motor lever at the hole and found the travel from Off to On to be just 1". Sorting through my stock of metal offcuts I pulled out an assortment and I also found a knob on a bent lever which looked like it could be useful? Bits of angle iron and metal strip were measured and cut; from the bracket I installed the distance to full on was 4" so I cut metal to suit this drilling three fulcrum holes the lengths of metal being hinged in the middle. 1/4" holes were drilled throughout allowing both 6mm set screws and nuts plus three short lengths of 1/4" dia silver steel for the fulcrum pins these pins being drilled across axis near each end to accept a common split pins to retain them in position.
The pictures show better than text the design of the linkage which I put together; not very pretty but it works perfectly. The two halves of the linkage form an hinge and in the off position the hinge is a steep "V" but at the on position the hinge travels just past horizontal and is arrested by a flat piece of steel locking the motor on until the knob is actuated to release it.
At last the Clarke is now fully working as it should; the servo motor cost £160 plus the cost of countershaft bearings and drive belt etc but for around £200 and plenty of head scratching the Clarke is now a much superior and robust lathe than when new. I appreciate in order to sell such lathes for hobby use they are built down to a price but the circuit boards and motors supplied as original are just rubbish; I'm sure Clarke will do a roaring trade on these two items but not for me thank you I dislike expensive junk.
Since the servo motor has been installed I've used the Clarke a lot and now it's a nice little lathe capable of a decent cut which I hand feed; I dare not engage power feed with a decent cut applied due to the plastic gearing which I don't wish to strip but so far this Clark is a nice small accurate lathe although I certainly would never recommend anyone to buy one because the circuit board and motor are much too flimsy. I've enjoyed today and what a pleasure it is now to work in bright daylight in the garage under the new LED panel lights whilst it remains the usual black hole outside?
A couple of days ago I decided to upgrade the terrible tail-stock clamp; this flat metal plate clamp was rubbish it allowing the tail-stock to wobble all over the place so I increased thickness and length which has now made sliding the tail-stock more of a pleasure.
Next job is to have a go at installing a new Balata flat drive belt onto the bigger Lorch Schmidt lathe.
Hope this is of interest?
Kind regards, Col.
- Block of wood..JPG (177.17 KiB) Viewed 9438 times
- Servo motor..JPG (173.11 KiB) Viewed 9438 times
- Countershaft..JPG (180.77 KiB) Viewed 9438 times
- Off position..JPG (184.14 KiB) Viewed 9438 times
- On position..JPG (179.24 KiB) Viewed 9438 times
- Past horizontal..JPG (138.35 KiB) Viewed 9438 times
- From front..JPG (175.76 KiB) Viewed 9438 times
- New clamp..JPG (151.94 KiB) Viewed 9438 times
- not that I'm hurrying you on 
