Forming splined form to round aluminium pot shaft

N_Cook Inscribed thus:

There is one major problem to overcome ! For any given spline pitch there are fixed diameters where the spline won't over ride ! You basically want a fixed size forming tool for a particular diameter. In which case there are companies that manufacture gears and I'm quite sure that for the right fee they would supply a steel gear that could be case hardened to do what you want.

Yes as in knurling, the pattern repeats for only one diameter and a certain degree of intrusion. Aiming here for 16 around a nominal 6mm spindle. Proof the concept works. Robbed the steel gripper wheel from a butterfly can opener, sharpened the points a bit and opened out the central hole. Mounted in the pipe cutter and produced a neat ring of indents. These were about 2mm apart and 7 equally spaced around, when cutter advanced far enough in. So a cog with 1mm spacing should work even easier as long as not too wide. Actual splined shafts have a 1mm spacing and 16 around. If nothing else a thin approx 1mm tooth spacing cog from a clockwork clock mechanism would make an excellent way of marking pot shafts before making axial cuts with a grind wheel.

N_Cook Inscribed thus:

Actually it would be any diameter where the distance could be divided exactly by the pitch.

Good test ! The aluminium must be fairly soft then.

I noticed you mentioned a Dremmel tool earlier.

OK so you know the pitch, you know the length of spline ! That information should be enough for you to find a steel gear with the right tooth profile and pitch.

There must be dozens on the net ! Google should help with those.

There is an engineering company just down the road from me and they tell me that they no longer cut their own gears but buy them in because its cheaper. They did ask me if I wanted any of their old cutters, but alas I don't have any means to use them.

I do have a tool & cutter grinder with a dividing head that will do 10 degree steps but I don't have any abrasive wheels small enough for that kind of profile otherwise I might have a go at making a wheel myself.

It looks as though the pitch between crests of the gear wheel would have to be about 0.8mm for it all to work. I may make up some sort of dividing head, for light inaccurate work, as not the first time I could have used one.

You can buy these pots you know!

Ron

The dividing head is a small 3" chuck with what looks like a 35 tooth gear at the back. A spring loaded peg just drops into the gap between teeth. There is a large knurled nut at the back which is tightened to stop any movement due to vibration. I use it mostly for sharpening drills and end mills.

Fiddle-faddle. :-)

If all you need is a force-fit of a knob on a shiney/slick shaft, use large Vise-Grips (tm) ("locking pliers") to bunger up the shaft with the pliers' teeth in the section the knob will slip on to.

No long division required. :-) WFM, Jonesy

No use telling that to the intrepid N.Cook! I am always fascinated by his amazing "repairs" and "modifications" - they remind me of a bygone era of make do and mend. I cant help thinking that Mr Cook doesnt do this kind of work to make a living, it surely cannot be cost effective to spend the amount of effort to effect repairs that he does. That said, I do have a sort of grudging admiration for his bodges and his attempts to improve reliability. It also has to be said that if it is found that one day one his repairs or modifications is deemed to contribute to a fatality - i.e. by causing a house fire or some other event he will be well and truly shafted. Sometimes it is very easy to believe that you are improving something without understanding the full story of why it was designed that way in the first place. Nine times out of ten it is because of cost, but not always.

Roy

certain

can

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So a

Actual

clock

making

There are just too many variables

I would rather crack on adapt and finish a job by bodging or wiring in, upside down, or whatever, than trying to find a supplier of a particular pot from all mannner of kit from 1940s to the presnet day.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Thats an option I'd not thought of. Find some 1mm spaced ridged steel and stick to some "mole grip" jaws. Squash and turn a few times, plastic knobs usually so no great precision needed.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Actually, there`s probably the germ of a good idea there, if you could find or make a suitable hydraulic press, and make up some half round 'jaws' with the correct tooth pattern, you could probably form the aluminium of the shaft quite easily, band sawing in the slot after cleaning up.

Ron

that

the

Squash

needed.

Find some fine pitched , BSF ,UNF or metric ordinary steel, non-hardened , bolts, but as large a diameter as possible. Hacksaw some "chord" sections off and braze to some vice jaws sounds plausible.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Or rather fine pitched nuts, sliced down , due to the concavity, there is then a lead in formed on the Al and the lead out side is irrelevant. Pinch the matching bolt in place between the segments while brazing onto the jaws for alignment

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Try asking on the right newsgroup: news:rec.crafts.metalworking

Well, I was thinking of a somewhat more elegant solution.

I don't quite follow how you would use a nut as as die, surely that would put a thread on the shaft rather than a spline?

is

the

Just small sections

You know the way some of these splined spindles are also serrated - I wonder if someone has been here before. Anyone know how to smash a large and course file into pieces ? and then grind down a couple of bits and then fix to the jaws of some lock jaw pliers. Grind in at 4 bites and then hold in a vice there and bash with a hammer ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

of

elegant

let

roller on

in

to be

of

justify

The last time I was there it took ages before someone came up with the name of the machining process for the step and repeat chiselling for forming those large aluminium heatsinks, found on domestic amps of the 80s, with those distinctive curved fins, - its called skyving.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Ahhhh you almost had me there... April first aint it!

I've returned to the pipe cutter idea. I've opened out the slot from 3.5mm to just over 5mm and it will now hold neatly and freely rotating, a 16mm diameter x 5 mm ball race. I know I can grind into the outer race with a Dremmel and thin disc (freehand) and cutting 1mm spaced teeth is possible as proved by cutting ,freehand so rough, some 1mm spaced teeth around a steel washer. Running a

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on