Stuff your 3D printer has made today...

[Screwdriver]

It might work but that's a LOT of unnecessary plastic! and why is the spiral itself so thin? Might just as well be 1:1 like an incredibly coarse acme.

If you're doing it on a lathe anyway, I would use the cross slide and have a belt take-off drive from that to rotate the workpiece.

Cross slide advances the workpiece, the rotation of the cross slide handle rotates the workpiece via the belt/gear reduction. Calculate the correct gear ratio and you'll get the desired spiral.

 

[Screwdriver]

At the very least, multiply the "thread" on your spiral to be multi start. You could probably get three more on there for rigidity. I'd double the diameter of the spiral too. Your first test jig looked more stable, I'd be worried about a 3d printed part hanging out further as the cut progresses.

 

[Onoff]

Calculate the correct gear ratio and you'll get the desired spiral.

That's beyond me unfortunately and I'm running out of time on this.

 

[Onoff]

I'd double the diameter of the spiral too.

You mean the "shaft" with the spiral on or the spiral itself?

Hand sketches welcome!

 

[ukracer]

You mean the "shaft" with the spiral on or the spiral itself?

Hand sketches welcome!

How are you producing the stainless part to cut the groove into?
Or is that just a collar/Bush as in your latest model.

 

[Onoff]

How are you producing the stainless part to cut the groove into?
Or is that just a collar/Bush as in your latest model.

Get a bit of stainless bar, face off, turn down to 34mm OD. Drill / turn a 24mm hole up the middle. Part off at 32mm long.

Or I was thinking to initially drill and tap it M16. Screw that onto the end of the 3D printed shaft. Later on bore out to 24mm.

 

[Onoff]

Mate's just got a posh sink. Was worried about the feet on the drainer marking it. Cue 4 feet in black TPU, one pair 10mm taller:

 

[ukracer]

Lad's just knocked this up. Self explanatory I hope, yellow is the workpiece.

Can be held in a lathe or mill:



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A little concerned whether the printed nut will hold the workpiece on the M24 thread without the workpiece spinning when being cut.

I think it's got a good chance of holding it with a very light cut on a 3mm cutter.
I would try and have a go but as time is against you I don't have that currently either.
Looking at that last model you could throw that straight into a milling vice and fit a handle to rotate it.
Again if time was not against you that would be a brilliant Sunday nightcap for @doubleboost as you could parcel up the collar already fitted to the plastic contraption and it would not need anyone to have a 3D printer the other end.

If you added a couple of through holes in the jig you could adjust them to create enough friction to make it hard to turn so the operator had better control.

 

[ukracer]

Get a bit of stainless bar, face off, turn down to 34mm OD. Drill / turn a 24mm hole up the middle. Part off at 32mm long.

Or I was thinking to initially drill and tap it M16. Screw that onto the end of the 3D printed shaft. Later on bore out to 24mm.

Ok so it's a collar you are ending up with but with a spiral groove in it.
More work to drill and tap it but it would ensure it does not move while machining.
My concern would be less of it moving but moving the part slow enough so the 3mm cutter did not grab and break.

As you say time is against you so finding the closest person to help is probably best bet but the part is starting to cost a fortune then (if you only count the fiel it would be a lot)

I am not being much help am I ?

 

[Screwdriver]

You mean the "shaft" with the spiral on or the spiral itself?

Hand sketches welcome!

Rough sketch:

I'd include a short section of square drive for the part and superglue the workpiece to the square insert. Machine the part, burn out the sacrificial "holder"

I haven't shown that on this sketch...

 

[Screwdriver]

 

[Onoff]

Rough sketch:

I'd include a short section of square drive for the part and superglue the workpiece to the square insert. Machine the part, burn out the sacrificial "holder"

I haven't shown that on this sketch...

Thanks. The spiral groove in the workpiece is at a 45deg angle...not sure if you're spiral is.

Should have said I need 2 grooves, 180deg apart.

@ukracer believe me I've been trying to find someone to make it, hence resorting now to this 3D jig and having a crack myself.

 

[ukracer]

Thanks. The spiral groove in the workpiece is at a 45deg angle...not sure if you're spiral is.

Should have said I need 2 grooves, 180deg apart.

@ukracer believe me I've been trying to find someone to make it, hence resorting now to this 3D jig and having a crack myself.

Contact @doubleboost that might push his viewers over the 100,000 Mark.

 

[Screwdriver]

Thanks. The spiral groove in the workpiece is at a 45deg angle...not sure if you're spiral is.

Should have said I need 2 grooves, 180deg apart.

@ukracer believe me I've been trying to find someone to make it, hence resorting now to this 3D jig and having a crack myself.

It a rough undimensioned sketch. You do not need two grooves. All you need is for the jig to advance linearly at a given rate while the shaft turns. The number and dimensions of the spriral on the jig is irrelevant.

You tell me you need 45º so for example the linear advance could be 1 inch for 1 turn (as per your design), i.e. a 1 tpi thread. That is crazy coarse, the backlash will be huge. You could use a 10 or 20 tpi thread to drive the part forwards but independently rotate the workpiece using whatever turns the thread but with a reduction gearing of 10 or 20:1 with gearing or a simple pulley.

 

[ukracer]

Thanks. The spiral groove in the workpiece is at a 45deg angle...not sure if you're spiral is.

Should have said I need 2 grooves, 180deg apart.

@ukracer believe me I've been trying to find someone to make it, hence resorting now to this 3D jig and having a crack myself.

Once screwdriver has perfected the angle on his jig. If he sends it to me I will see if I can do mild steel (I don't have any stainless). In the meantime I will look for some stainless.

It will be much quicker to print than the large jig.

 

[cheb]

A handwheel for a Whale Gusher 25. Made form orange PLA because that's what's in the machine. I doubt it will last long, but the intention is to make one from aluminium. First I need to get the aluminium...

 

[Screwdriver]

Once screwdriver has perfected the angle on his jig. If he sends it to me I will see if I can do mild steel (I don't have any stainless). In the meantime I will look for some stainless.

It will be much quicker to print than the large jig.

Wait. What! It's a rough sketch of someone else's jig and if I was going to make one, I wouldn't do it that way.

Anyway, just for you:

I'm not even sure if the OP really wants 45º... but there it is anyway.

 

[Onoff]

Wait. What! It's a rough sketch of someone else's jig and if I was going to make one, I wouldn't do it that way.

Anyway, just for you:

I'm not even sure if the OP really wants 45º... but there it is anyway.

Yes, it must be 45deg. I'll CAD it up properly when I get home.

Won't the lever arm on your design be far greater than my lads idea?

 

[Screwdriver]

How do you mean lever arm?

FWIW I assume you will be putting a great big lever or wrench where I have put the hex end for better control while cutting.

I **think** you only need to turn it a quarter turn anyway (which is another area the design could be greatly improved. It doesn't need to cut a full spiral (I assume).

Also, thinking about it, you could make the spiral form hollow and slide it onto a suitable steel bolt... Superglue works wonders with plastic prints.

(It it still your idea, I have merely tweaked it since I happen to be sitting here Sketchuping)
(I was waiting for Yodel to deliver and watching them do a great big circle aroud me until finally they delivered my van battery)
(Dropped bent and broken of course so now I am chasing up with Tayna...)


(I might be starting to experience sense of humour failure)

 

[Onoff]

I was waiting for Yodel to deliver and watching them do a great big circle aroud me until finally they delivered my van battery

That's going to hurt when the courier trys to drop kick it over your fence/gate!

Lever arm, distance from where its held in the tool post to the cutter.

Yes, it's about a quarter turn only. I'd already (I thought) picked up on this with my lad and made the assembly a bit shorter on the MK2 version. Figured we could make it even shorter and perhaps with physical stops at the start and end of the cut.

This started on the quiet as I didn't want the person it's for maybe seeing it. Tried modelling the thing to start with and failed to get it perfect as did my lad & a few other kind souls on here who had a go.