Help with Fusion 360 designs

[sako243]

Teeth in OP are tapered.

They're tapered to the centre so I'd have thought provided your milling cutter is at least as narrow as the inner gap you're fine - you'll take have to take more than one pass.

To be honest I'd probably turn and mill it rather than cast it.

 

[Maker]

Hardest part to my mind is measuring it accurately, but I'm always looking for an excuse to buy a toolmaker's microscope.

The teeth on the original don't look tapered to me but if they are, I'd draw the profile at the base of a tooth, create a plane offset the height of the tooth from that surface and draw the profile at the top, then "Loft" a surface between them.

Then use a circular pattern to create however many teeth there are.

 

[graffian]

I printed it in PLA and had it lost wax cast in bronze

What do you give them, a mold to cast the wax into or a wax part.

 

[Screwdriver]

I'd be wondering if a plastic part might even actually work in this circumstance. I certainly would't think something so small and fiddly would be that easy to cast anyway. Plus of course you would still need to machine a cast part.

Why not go full "Clickspring" mode and fabricate from brass? Turn most of it on a lathe, cut the teeth with a hacksaw and file it to perfection?

For extra man points, make your own files...

 

[mike os]

To taper the tooth you need to loft it as maker suggested then add fillets, then a circular array if the completed part

 

[bigegg]

They're tapered to the centre so I'd have thought provided your milling cutter is at least as narrow as the inner gap you're fine - you'll take have to take more than one pass.

To be honest I'd probably turn and mill it rather than cast it.

Tapered in the axial direction as well.

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

 

[ukracer]

Tapered in the axial direction as well.

Nothing a file can't sort..... remember stonehenge.

 

[DAPPH]

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.

Gluing it up is not an easy option , when it split the end of the four foot long driven shaft walloped one broken side harder than the other & bent it some 8 mm out of a true circle as it tore free and bust the thing apart .

I've slowly but surely been assembling everything for casting in brass and lower heat metals & alloys for the last 20 months or more .. reckon I'm just about ready to go .

I've already got hard wax modeling was that can be turned on the lathe if needed & jewelry grade melt-able siicone rubber compound to make the moulds.

If I can't print one , casting hlf of it will the direction i'll be heading . I'll can cut the spool in half vertically , filing to a scribed line on both cuts so as to get as near as dam a prefect half diameter spool . I can dremel drill and insert wax pins to hold it together . Then I'll make my mould and cast the wax . I've already got the instatement powder to make a precision casting and a home made burner & crucible to melt the alloy . might set up an old cycle wheel on a sturdy post in my work mate to make a simple centrifugal spinner to get the melt in every crevice .. If it fails a few times I'll still have the mould to make more lots more wax forms .

The final thing if I cant print one is to buy one from Sears in the USA who carry a large range of common spares for all the Craftsman / Atlas ( my Lathe is a British lease lend USA made Atlas badge as Sphere ) lathes @ $ 39 plus about the same in carriage and taxes .
I'd rather use my skills and make the part myself ............... it keeps me out of trouble and my mind gainfully occupied .

 

[daedalusminos]

Like this...

 

[DAPPH]

Something like this:
View attachment 244888

View attachment 244887

Thanks Ed I was running through my mind how to loft the smaller tooth top end dimensions the length of the teeth to give the tapered axial lead in . I suspect It can be done with offsets and then loft it vertically & let the programme join the edges up correctly .

 

[daedalusminos]

Better image...

 

[awemawson]

What do you give them, a mold to cast the wax into or a wax part.

The PLA burns out just like the wax so long as the burn out kiln is 650 C or there abouts and has reasonable air flow to convert the residual carbon to carbon di / mon-oxide.

Having had this done for me some months back has kicked me into resurrecting my set up that I had years ago - I've got the kiln working (12 kva pottery kiln) and the furnace (100 kva Induction furnace) and i'm in the final thrashing about stage getting the foundry building as safe as possible and accumulating all the PPE. Rather a long thread here describing it:

https://madmodder.net/index.php/topic,13100.0.html

 

[DAPPH]

Like this...

View attachment 244917

Yes but the top end of the tooth is a few thou smaller than the base area so as to help selectingteh gear a bit easier . The female gear the dog / collet slides into also has this slight lead in.

I'd rather try to get the best precision lost wax cast fit of mating of surfaces , than take a warding file to the teeth & try to do a mk 1 eyeball & engineering marking blue bench fit for all 12 teeth as I'm nearly 70 yrs old & my birth certificate is fast running out . Though I do have a couple of scrapers small enough it's time I'm short of .

 

[daedalusminos]

Yes but the top end of the tooth is a few thou smaller than the base area so as to help selectingteh gear a bit easier

As it is in the model

 

[awemawson]

As a matter of interest, before that dog clutch was cast I used the PLA original in anger. This is a dog clutch that drives powered tooling on a large CNC lathe and the PLA stood up to it amazingly well

 

[daedalusminos]

Start a new sketch, draw 2 circles, one for inner diameter, one for outer. Draw a line from centre extending outside outer circe. Create polar pattern and create 12 line. Join the end of 2 of those adjacent lines with another to make a closed segment...

 

[DAPPH]

Better image...

View attachment 244919

Yes that looks to have the lead in angles ... what did you do ? Please tell . I can print two off to make the full height , orient / align the teeth in the same plane then super clue them togehter with Special Delrin Super glue

 

[daedalusminos]

Select the segment and extrude it down and taper by the calculated taper angle (2.434 degrees) - and create a new body

 

[sako243]

Incidentally (assuming I've interpreted them correctly) then the dimensions you've given don't quite tie up.

0.65" inner diameter, 0.95" outer diameter, assuming you measured straight across rather than around the curve then maths says (as illustrated below) the outer diameter should be 275 thou rather than 232 thou. Obviously that might be wear or by design but essentially you'll have a larger gap on the outside of the tooth mesh compared to the inside.

 

[daedalusminos]

Now select the 12 ring segments between outer and inner circles and extrude down half the total height...the edit box here isn't quite right but you get the idea