Help with Fusion 360 designs

[DAPPH]

Help ...
I've bust a selector double ended dog on the forward /reverse change box on my lathe when doing a cross cut under power of the gears . My hand slipped off the pull to stop the drive knob just as it was getting to the limit of the travel . . I want to make one in the same sort of alloy aluminium using the lost plastic casting method. Everything on the lathe is in Imperial measurements.... it's 77 or more years old

I'm having trouble getting the tessellated dog teeth / ends on the sliding dog collet body, they are not parallel cut teeth . They look a bit like the old concrete painted white ordnance survey trig points ( but a hell of a lot smaller with less inclines )
The max dia of the spool is 0.950 thou and the internal through 650 thou , there are six teeth in the same alignment at the both ends of the collet , tooth height is 0.200 thou at each end total length of the spool is 0.950 thou
Now for the bit I'm struggling with , there are six evenly spaced dog teeth with the same gap between them . Outside width of a tooth is 0.232 at the root & 0.215 at the top outer end . On the inner side of the tooth a root 0.188 thou & 0.1175 thou at the top end . So basically the teeth are tapered equally going back and also equally tapered vertically to allow an easier feed in . the top & bottom of the sliding dog collet are flat like a cotton reel


Can any one give me pointers how to go about doing these tapered dog teeth please in Fusion 360 ? I've been thinking it may be a three part design that get glued / fused up after printing
Initially I thought I'd be able to turn one up on the lathe but the taper angles of the teeth to such fine tolerances are not re-produce able on my lathe with the kit I've got.

 

[daedalusminos]

A photo would help, but from your description you might be best cutting the slots out of the top of the cylinder tol leave the teeth.

But in any case you'll have to post machine the casting

 

[DAPPH]

I'm having difficulty in moving the photos from my photo file click drag & drop to the post every time I pick up the picture I get a prohibition circle notice saying photos are not available to transfer .. sent them to documents & get the same message . Arrgh I just love this windows 10 . I have put up numerous pictures before but haven't a clue as to how it's changed nor why unless it is part of an automatic up date that is trying to guide me to using a particular set up (it's not unknown for this to happen , is it? )

 

[bigegg]

I know you asked about fusion, but...

Could you glue the part back together (superglue?), and take a mold from it? (Latex, or (100%) silicone sealant [1])
Then do a lost wax cast?

[1] water + washing up liquid in a bowl, empty sealant into it, and knead under the water. It sort of turns into a "putty" that wont stick to stuff(except itself) and will cure even in thick sections.
It *has* to be 100% silicone though.

 

[bigegg]

I'm having difficulty in moving the photos from my photo file click drag & drop to the post every time I pick up the picture I get a prohibition circle notice saying photos are not available to transfer .. sent them to documents & get the same message . Arrgh I just love this windows 10 . I have put up numerous pictures before but haven't a clue as to how it's changed nor why unless it is part of an automatic up date that is trying to guide me to using a particular set up (it's not unknown for this to happen , is it? )

Click "upload a file" button under the reply box, and browse to the picture, rather than "drag'n'drop"?

 

[DAPPH]

Well FMOB !

Just clicked picked dragged & dropped them in .

 

[DAPPH]

Yes ,I know they are duplicated ..I'm quitting whilst I'm ahead .. And NO that's not hairs on my thumb prints .

 

[DAPPH]

Click "upload a file" button under the reply box, and browse to the picture, rather than "drag'n'drop"?

Thanks

Ha , sussed it just picked these half an hour ago

.

 

[daedalusminos]

Those teeth don't taper along the height by the looks of it, in which case I would sketch each tooth, extrude then array

 

[Screwdriver]

Ouch! Yes that is a complex design, way, way beyond my current level.

There's probably a button or setting in Fusion that will project a profile while simultaneously adding a taper, in the right mode it would probably do all six in one go.

All you have to do is find that button.

 

[bigegg]

I'd model a cylinder.
Create a sketch on the end, create a 12 sided inscribed polygon. Join the vertices.
Then a concentric circle for the internal bore.(extrude>cut the bore)
Then extrude>cut the teeth, you can extrude with a taper in the settings.
Move to other face of the cylinder.
Project the teeth.
Extrude>cut the opposite teeth.
Then tweak as neccessary.
For the centre groove, create plane> offset plane from cylinder end
Create sketch on plane. Concentric circle. Extrude>cut

 

[bigegg]

For a one off, i'd not worry about the exact shape of the teeth in your casting - shrinkage will cause inaccuracies so you'll have to tweak
Get them something like, then file to size.
It's only aluminium!

 

[ukracer]

Ouch! Yes that is a complex design, way, way beyond my current level.

There's probably a button or setting in Fusion that will project a profile while simultaneously adding a taper, in the right mode it would probably do all six in one go.

All you have to do is find that button.

Try asking @BelgiqueB he has offered to assist if you can send you fusion file with how far you have got.
If we can get people to create short videos they will only need to do it once.

If you send me a drawing with dimensions I will have a bash creating one out if aluminium as I need the practice with my rotary table.
It won't be quick though as I have an important prototype I am developing this week.

 

[bigegg]

To get the taper on the teeth, an alternate method is
Create cylinder
Sketch on end of cylinder
Draw end profile of tooth.
Circular pattern around cylinder axle.
Create Offset plane to bottom of teeth.
Create sketch.
Draw profile of tooth base.
Circular pattern around cylinder axle
Create>loft teeth profiles.

Repeat at other end of cylinder.

Extrude>cut bore

 

[awemawson]

Here's a broadly similar part I did in fusion 560. Actually I printed it in PLA and had it lost wax cast in bronze

 

[tom2207]

why not just machine it ,,, instead of casting it

 

[awemawson]

That dog clutch is almost impossible to machine without custom ground tapered cutters - see the 'teeth' are tapered - whereas a PLA master and bronze casting required no special tools . . .

. . . but the OP's part is pretty simple to machine as the teeth are straight cuts

 

[sako243]

Not familiar with Fusion 360 but use Inventor quite a lot and I'd start a sketch on the cylinder end. Draw a circle a larger diameter, draw a radius line joining centre to outer and then set up a repeated pattern, close in the ends and you can cut into the top then a certain depth.

If any of that made sense...

 

[bigegg]

That dog clutch is almost impossible to machine without custom ground tapered cutters - see the 'teeth' are tapered - whereas a PLA master and bronze casting required no special tools . . .

. . . but the OP's part is pretty simple to machine as the teeth are straight cuts

Teeth in OP are tapered.

 

[sako243]

Something like this: