The PF Bolt and Thread guru thread

[Gammaboy]

Do you have access to a spare length of the shaft? It will be pretty easy to turn it into a thread chaser with an angle grinder....

[Jack Nicholson]

Just ugga dooga it up with the rattle gun.

I may try this with the nuts that I've ordered, assuming all other avenues are exhausted.

If I can help with shipping anything to you please let me know.

Cheers, the nuts & threaded rod are from eBay & coming here through the global shipping program, so that's no problem.
Could be that the supplier of the die won't ship international, so I might take you up on that offer, depends how things turn out.

There was a mob in Coburg Vic who specialized in making acme thread and nuts about 10 years back, a mate bought a 6ft length from them for a lathe - can't remember the name unfortunately. Failing that, hare and forbes might have something off a cross-slide or compound that would fit? I might try Graham McDonald Services out at Girraween to see if they can see a problem with your nuts first....given limited measuring equipment.

The old bloke at Lee Bros said there was one mob in Victoria who had ACME threaded rod & nuts, but they were only in one size and it was an odd pitch 6 TPI or something, because it was being used in some specific machinery.

I was at Graham McDonalds on Wednesday, we tried the taps they had one the shelf, they didn't have any dies though.

If i'm going past Hare & Forbes i'll stop in and have a look.

Problem no doubt, he's been turned away for a piddly job.

Yeah this is a headfuck no-one want's to take on it seems.

You could use the taps that you have to check the thread pitch of the stud. If it is what I think it is, the thread could be stretched, which would cause the jamming you're experiencing.

I don't have a tap in my possession, because $200

Also the taps were pretty loose in both the original and the new gears, so it did not appear that they would be of any help.

EDIT the stretching crossed by mind, but seems kind of doubtful, it's a little pissy electric motor driving this gear via a cable & worm gear. Also it's steel, pretty tough, and if it was stretched you'd expect the original gear to be jamming up on it too, but it spins freely...

Also, if you can force the tap with a (not running) lathe/drillpress/etc as you wind it through, you might gain enough clearance for it to work, assuming it's not binding on the crest. Obviously this is rough as guts though.

You mean put some lateral load on it, like making a hole bigger with a drill by wiggling it around? Maybe, but that would mean buying a $200 tap...

For now I just have to wait until the nuts and rod turn up, and then I have some "gauges" to play with.

[Jack Nicholson]

Do you have access to a spare length of the shaft? It will be pretty easy to turn it into a thread chaser with an angle grinder....

Unless I can pull a pedal box out of a wreck for less than a carton, then no, have only got the one.

[bpm]

Why don’t you remove the plastic from the centre, drill out the brass gear and press fit the centre of the old gear into the new gear?

[gxxr]

Just another idea, Mick Moyles at Summer Hill might be another possibility. It's an Aladdin's Cave of shit, bordering on hoarding, but lots of obscure bits and pieces which might include nuts.

If I was going to modify the gear, you'd have to make a fixture or make soft jaws to hold it to avoid damaging the brass in the chuck. Part of the machining issue, will be the need to buy inserts for most people.....not all that common a requirement and they'll sit on the shelf forever waiting for the next use - or single point grind some hss.

[Tripper]

CNC and cupcake world, on ebay

[Jack Nicholson]

Alright my threaded rod and nuts arrived from the US....



Unsurprisingly the original gear is a bit loose on the rod. The new brass gear is a bit tighter, but moves ok if not with a little chatter. The nut feels about the same a the brass gear.

I cannot get the new nut onto the original spindle more than a half turn, it binds up even worse than the brass gear.



So, options now...

Buy that die for $100 USD + $??? shipping, and recut the thread on the spindle....

Or what are the chances of making a die or dies out of these nuts?

[Greg Rust]

Get a thread gauge and measure them.

[Gammaboy]

I'd seriously look at stripping the black plastic off the steel insert and machining the brass thread out. Hell, if i could actually use my lathe at the moment, I'd offer to do it for you.

[Jack Nicholson]

The PF Bolt and Thread guru thread

Get a thread gauge and measure them.

Without trying to sound like a smart-arse, what is a thread gauge going to tell me that I don't already know?

The thread is clearly not a common off-the-shelf standard, these rod and nuts are a standard, and the closest one there is to it.

Modifying the thread on the spindle to a standard thread with a standard die is going to be a lot easier and cheaper than "custom".

Or am I missing something?

I'd seriously look at stripping the black plastic off the steel insert and machining the brass thread out. Hell, if i could actually use my lathe at the moment, I'd offer to do it for you.

Appreciate that but the problem is I have three of these cars to do; my own and two customers, and probably more in the future. That's why i have three brass gears here.

Whatever the solution is, it needs to work quickly on the next two. Removing the original gear and re-working it outside somewhere each time is not really practical for the next two cars...

But what about making a couple of the nuts into dies? Looks like a few holes milled in the nut, a tapered grind on one side, harden them, and it might work?

Looking at my other dies, it seems kind of doable, but I have my doubts since the nut is kinda loose on the rod...

[GSRman]

I bet the depth of the thread is non-standard.. although running the 11.4mm through it 'should' have fixed that - unless it's galled it up..

also looks like the outer edge of the thread is thicker on the car? in which case nothing you can fucking do.. except put it in a lathe and re-cut it..

can you buy the part from another car? enough that you can find a hobby machinist that could make you nuts?

[BigMuz]

Normally you need the make part to make the female part. The difference between going on half a nut and sloppy as hell is a couple of tenths Max. Can you find someone with a lathe to scratch it a bit deeper? It's a pretty simple job.

[Jack Nicholson]

OK so might have a bit of a breakthrough on this. Stopped in an another machinist (guy who did some work for me a few years ago) and explained/showed him the problem.

There is ACME thread, then there is Stub ACME thread. Seems likely that the spindle in the car could be a Stub ACME thread.
He pretty much told me to eat a dick when I asked if he could cut me a female Stub ACME thread in 1/2"-10 though...

Stub ACME being the same pitch, same 29deg, but the depth of the threads is shallower. So you can screw a Stub ACME nut onto regular ACME male thread, but not vice-versa.

Looking at the ACME threaded rod I bought in, compared to the spindle in the car, yeah the threads on the ACME rod are much deeper, even just by looking at them.

In theory, you could run an ACME die over the Stub ACME thread and cut them a bit deeper. Which is where i'm at now...

[Gin Kii]

So different minor and major diametres... kinda what I mentioned in my previous post.

[Jack Nicholson]

The PF Bolt and Thread guru thread

Finally...

My 1/2-10 ACME die arrived from the USA



Made in fucking China of course...

Had to get a 27mm deep socket...



But it recut the thread on the spindle and the brass gear spins freely on it now.



Because the die is symmetrical, thread can be started on either side, I couldn't cut the last few mm of the thread on the spindle, but that's about as good as it's gonna get...