How would you make that.

OK. A "how would you make that" question. I'm looking at 2 or 3 of each part.
Item one is a plate, 2.5" diameter, that fits on a taper drive and has
the rather odd 6, 1/4" round buttons on the face. How would you make that?
http://farm5.static.flickr.com/4082/4849990149_3d7a75843e.jpg
http://farm5.static.flickr.com/4114/4849987329_837fbdb6ab.jpg
The second ietm is a drive plate, about 4" diameter, that meshes with the buttons on the previous item. What's the best way to approach this? I would guess a boring head on a rotary table but other clever ideas welcomed. Both are hardeded after machining.
http://farm5.static.flickr.com/4082/4850387713_151d8b16f7.jpg
http://farm5.static.flickr.com/4135/4850393609_2e8168de92.jpg
Thanks
Charles
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I can't really see why either of those are complex enough to require much thought on fancy production methods. Item one is simple turning followed by welding the buttons into place in their location holes. Item two is simple turning plus a boring op on a rotary table as you say. What else are you expecting anyone to come up with?
--
Dave Baker



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Thanks Dave
I should have said that since the items will be rotating at up to 6000rpm I won't be welding the buttons on!
Charles
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Thanks Dave
I should have said that since the items will be rotating at up to 6000rpm I won't be welding the buttons on!
Charles
===========Look like some kind of cush drive?
I'd be inclined to align the two and ensure the six sets of holes for the rubbers (or whatever) and pins are initially bored in line before opening out the large sockets, probably locating a good fit in the centre of the flat plate on the shaft on the "driving" plate (your marking out may be more accurate than mine, though!). If they're turning at 6000 RPM you may want to leave some surplus material to allow for balancing (prior to hardening!).
As to the pins... shrink fit? Were they to pass fully through the flange I'd be concerned that there isn't a lot of material surrounding them and you might get cracking on the outer part of the flange, a high-strength adhesive might be a better idea (with a couple of thou relief on the pins to allow for the goo). Would be a sod to machine them in place, so I'm presuming they're made separately!
Just my tuppence worth!
Dave H.
--
(The engineer formerly known as Homeless)

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On Aug 2, 11:43am, "Dave H."

Thanks. Not as simple as a cush drive. It's a "petal" type of drive that allows two components to rotate at the same velocity when their centre lines are different. In this case the main drive goes into the plate with the pins and the plate with the holes is offset. The application is in a vane supercharger. I suppose the benefit is that it's a very compact arrangement. The pins and plate are made as one on the original.
Charles
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Charles wrote:

If the pins really need to be an integral part of the disc for strength reasons then I'd do all the turning, mill away the rough between each pin just leaving enough material and then finally form them into round pins with a trepanning tool which you can make out of scrap fairly easily. I have made similar things for machining out valve spring seats on cylinder heads. Basically a boring tool but with the cutting edge facing inwards.
Doesn't need to be much more complex than a bit of square bar held horizontally in the mill off a mandrel and drilled at one end to take something like a 1/4" round HSS boring bar with a grubscrew to lock it in place. You can create size adjustment potential easily enough just by drilling for the boring tool somewhat off the vertical so the further down it sticks the smaller the cutting diameter. You can then set it to size against a dial gauge after taking a trial cut on some scrap.
It helps to grind a flat for the grubscrew on the boring tool so it always keeps exactly the same orientation. That means the relationship between depth (amount sticking down) and cutting diameter stays constant every time so if you do the trig at a known angle you can actually set the cutting diameter with a dial gauge on the top of the tool to indicate the depth. Just slacken the grubscrew a tad and tap the tool a bit further down to reduce the cutting size.
Sine of the angle is what you want so for a 10 degree angle every 10 thou further down on the tool gives you 1.7 thou reduction on radius. You get very accurate adjustment on diameter that way due to the multiplication factor. You just need to get the starting position of the hole for the tool in about the right position for your target size.
To be honest it doesn't seem as if your application requires a very specific size for the pins as long as they are smaller than the bores in the mating disc so anything close to 1/4" diameter should do the job.
--
Dave Baker



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Charles wrote:

Could you make the studs from suitably sized socket cap screws threaded into the plate and locked with nuts or a dab of weld? Depends if it has to look pretty or just do the job? Bob
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Bob Minchin wrote:

Scratch that reply - I should have read the other replies first. Bob
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http://farm5.static.flickr.com/4082/4849990149_3d7a75843e.jpghttp://farm5.static.flickr.com/4114/4849987329_837fbdb6ab.jpg
Make flange blank thick enough for all features. Attach to RT on mill, either by fixture that picks up on 2 holes in flange, or 4 Jaw chuck. Get the holesaw out a little larger in dia than the spacing between pins, Center the part to where you want the first pin. holesaw to approx depth. index and repeat 6x. This gives the boring head some clearance to work into. You should have slightly overlapping holesaw cuts, with the overlap in the middle of where a pair of pins are
Attach boring head (boring and facing head would be nice at this point.) Use boring head with tool backwards, so you are cutting the pin, not what would be a bore IYSWIM. I think you have to run mill backwards for this step. 'bore' OD of pin, in a many steps as required. Use a depth stop and you can face the area around it.
For center pin either turn in lathe, again maybe using a boring bar to reach round the features without coliding with the pins, or use the boring head in the mill as described. Bore hole and add keyway.
Does assume the pins are far enough from the center, compared with the distance between them to clean up the flange properly, else some lathe facing probably required.

http://farm5.static.flickr.com/4082/4850387713_151d8b16f7.jpghttp://farm5.static.flickr.com/4135/4850393609_2e8168de92.jpg
Face to thickness, add flange feature, then use a close sized holesaw to create the blanks, then bore to size
hth
Dave
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First part,turn leaving meat on for the buttons,then cnc mill. Second part,turn and mill. Cost a few bob to machine prior to hardening.Going to cost more than a few for grinding after hardening. Don`t P about making it out of seperate parts.
Mark.
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Thanks chaps.
Dave Sanderson's method is probably the one that I'll take since, as Mark cheekily knows, I don't have a CNC mill !
Charles
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.

How many would you like to buy (cnc mills)? :-)
What about your old mate in Long Eaton?
Mark.
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The only CNC mills that you'll have for sale wouldn't fit in my garage.
Might discuss it with the Long eaton CNC guru..........
Charles
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.

Sell you a bigger garage. :-)
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Be a doddle on my Beaver Partsmaster - but if I did it who's going to flail the feild, feed the pigs, and lay the next batch of concrete footings????
AWEM
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Andrew Mawson wrote:

I would have assumed that the landed gentry of Sussex would have a man to look after the land! lol
Bob
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Andrew Mawson wrote:

I'll come and flail the field. I drove a tractor once (1966 David Brown as I recall). Have tractors changed much in the last 40 years? ;-)
like this:
http://www.steelestractors.com/gallery/2007/Fiferally07/Fiferally07-108.jpg
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to
Brown
http://www.steelestractors.com/gallery/2007/Fiferally07/Fiferally07-108.jpg
Don't worry about the age of the tractor - I have a 1955 Fordson Power Major and a 1974 Ford 4000 !
AWEM
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Andrew Mawson wrote:

I saw one of these in action at Southwell ploughing match a couple of years ago:
http://www.aeroandclarkie.co.uk/images/tractor/8.jpg
Awesome!
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You not married then?
Mark.
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