Today I acquired...........

[angellonewolf]

I donnate to good life forms

as long as there not hammers for @Parm

 

[Parm]

as long as there not hammers for @Parm

Hang on a minute, let’s not go there

I’m currently due a hammer and an axe !

 

[awemawson]

Haven't seen thrupenny bits for a long time !

I have two bags of thrupenny bits in uncirculated condition if anybody lusts after them. I took then out of the bank when they announced their withdrawal in 1971 and still have them.

 

[25.4_mechanic]

... some parts for the Myfords, after a loooong way to me.

I am extraordinarily grateful to a fellow forumist helpful beyond measure for his patience, perseverance and collegiality in the face of the greatest adversity.

Thank you



First, a 3D printed tool acquired via eBay.co.uk for fixing the bullgear on Myfords when changing jaw chucks without losing teeth on the backgear.

This part is of really remarkably poor fit ... but see for yourself:

Top tip: Don't bye it!


I've been desperate to get this for a while, I finally saw the advantages of using it for parting off while relieving the front spindle bearing, let's see how it does, it's an original:

Included was this parting knife holder with a remnant parting knife.
The screws are recognizably dead, certainly not there from the beginning and with their drive also completely unsuitable to apply the necessary force to clamp the knife securely.

Fortunately, the three broken screws were sent with it and I unpacked my full set of thread gauges.
Since the parts came from British lands, I started with BSW, then UNF, UNC and even "4 to 42 V-Thread" - nothing wanted to match right and the damaged threads have not made it easy.

At some point I was fed up and took from my small screw stock any somehow suitable looking screw and tried .... fit on the first try - for whatever reason,
but it is quite a normal M3x0.5mm thread in the knife holder and I have several dozen of them.

Finally also these three Allen screws in the right length in stainless .... fixed!

A little cleaning and care would do any of the items good .... comes.


Been wanting one for a while, especially since I learned here how important a supported workpiece can be for good results:

After a while ago a fellow forumist already gave me a fixed steady rest, now I have an additional traveling steady in quasi-new condition.

I have also wanted this one for a while:

Whether it will allow me to disengage in between when cutting metric threads - which should not be possible they say
- I will now find out, but it is a helpful extension in any case.

This part also needs attention, but after a few drops of oil, it already works without complaint.


I wish everyone a wonderful weekend and thank you again to my brave helper!


Best regards


Carsten

--

 

[DAPPH]

A veritable Aladdin's cave of goodies Carsten
I think I'm right with this :-
The counter will simply turn as the shaft rotates so it will be a few trials of seeing where the graduations line up . If it's no good for metric perhaps make a slip over magnetic cap with one marked point for metric if they aren't accurate enough & run in from a fixed carriage stop block so you know where the thread starts

 

[The_Yellow_Ardvark]

Hang on a minute, let’s not go there

I’m currently due a hammer and an axe !

Pay you dues, then visit.
I will supply them to you. Plus a coffee.


Failing that I keep them.

 

[Parm]

Pay you dues, then visit.
I will supply them to you. Plus a coffee.


Failing that I keep them.

I will soon. You knew my predicament

 

[Screwdriver]

A veritable Aladdin's cave of goodies Carsten
I think I'm right with this :-
The counter will simply turn as the shaft rotates so it will be a few trials of seeing where the graduations line up . If it's no good for metric perhaps make a slip over magnetic cap with one marked point for metric if they aren't accurate enough & run in from a fixed carriage stop block so you know where the thread starts

I don't think that's right. A thread dial indicator only works with metric threads using a metric lead screw or imperial threads with imperial leadscrew. All the TDI does is keep track of the linear position of the saddle wrt the lead screw orientation. It is permanently locked to the lead screw so that when it rotates one full turn, the saddle has moved a known distance (typically one inch on an imperial lathe).

You can frig an imperial lathe to move in mm by using 254/10 steps (or a 127 tooth gear wheel etc) but the lead screw is a fixed number of turns of the TDI per inch. So far as I can tell, once you lose the relationship between the position of the gearbox and the orientation of the lead screw, the toolpath no longer tracks the thread pitch.

My guess is if you had a similar 254/127 ratio in the TDI then it might allow you to pick up the half nut where you left off. However you would then have to move the saddle an unfeasible distance and pick up the correct 254/127 "mark" before it fell back in phase...

Bit of a head scratcher to be honest but simply changing the dial face on the TDI won't help (I don't think).

 

[DAPPH]

I can cut metric & imperial on my antique Atlas using the same thread dial indicator & lead screw , nothing changes save for the change gears . I suspect Carsten will have change gears for metric thread cutting on his Myford lathe .

see :- https://www.model-engineer.co.uk/news/article/metric-myford-threads/27223

Such gears 3D printed if not readily available appear to be good for many lathes , as they are somewhat strong There might be some on such sites as thingyverse etc just ther for th paying a small fee and getting thm printed .

I can get a full set plus extra's for the Atlas , but if I wanted I think I could 3D draw and print individuals in ABS without much difficulty . Apparently a lot of modern home hobby lathes are using plastic gears as well as a few industrial ones.

 

[The_Yellow_Ardvark]

I will soon. You knew my predicament

Alas I do.
But you know were my smpathy is.

 

[Screwdriver]

I can cut metric & imperial on my antique Atlas using the same thread dial indicator & lead screw , nothing changes save for the change gears . I suspect Carsten will have change gears for metric thread cutting on his Myford lathe .

see :- https://www.model-engineer.co.uk/news/article/metric-myford-threads/27223

Such gears 3D printed if not readily available appear to be good for many lathes , as they are somewhat strong There might be some on such sites as thingyverse etc just ther for th paying a small fee and getting thm printed .

I can get a full set plus extra's for the Atlas , but if I wanted I think I could 3D draw and print individuals in ABS without much difficulty . Apparently a lot of modern home hobby lathes are using plastic gears as well as a few industrial ones.

You can cut a metric thread on an imperial lathe and disconnect the half nut?

That's news to me.

 

[Seadog]

Me too, Steve. It just isn't possible. Change wheels just give you the correct ratio. But, and don't quote me on this, the relationship between the TDI and the tool position is only correct every 127 turns of the spindle once you disengage the half nuts.

 

[Easywelder]

Have you cut anything yet?

No, got the table and engraver working fine but not enough juice to power the plasma where it is currently located, I’ve some infrastructure work to do as well as changing 3 phase supply from 100amps to 200amps(just a meter and fuse change, supply already there) so may buy generator as temporary measure needs 26 kva I think.

 

[Kram]

New grinder for finger callouses. Also good for abrading dirt out of your fingers. I needed to use the old one about 10 minutes after every climbing session, eventually wore out the motor, this has a bit more power to it.
Also comes with a razor blade skin peeler Nope. This bit will not be used.

https://www.amazon.co.uk/gp/aw/d/B09GXJKX9J

 

[Screwdriver]

Me too, Steve. It just isn't possible. Change wheels just give you the correct ratio. But, and don't quote me on this, the relationship between the TDI and the tool position is only correct every 127 turns of the spindle once you disengage the half nuts.

My intuitive self says that but when I try to describe it in words, my brain goes a bit soggy. Intuitively, the gearbox (and therefore the desired thread) is not geared in a low enough integer ratio like 4 or 8 to remain in phase with the lead screw by "hitting your mark" to re-engage (when cutting metric on imperial). You can't just use 254/127 marks on the TDI because 1. that would be impossible to see and 2. the coarse teeth would not necessarily engage at that exact point. You'd need a massive 254/127 tooth 8tpi pickup for the TDI and it would have to travel miles before you hit the correct mark to align with the leadscrew/gearbox.


Similar situation with a carriage stop. Once you have lost the phase relationship between the lead screw and the gearbox (by disengaging the half nut) the linear position of the saddle does not guarantee the half nut will re-engage in the same phase.

Interesting observation that the TDI would have to turn 127 times to re-synch itself, that does sound right. 127 is prime so there's no escaping it by cleverly dividing the dial face. Why they made it 25.4mm to the inch god only knows. There's probably a good reason but my brain is fried so you'll have to ask Google or @Seadog, he'll know...

 

[Seadog]

The figure may be wrong, in fact I'm almost certain that it is. But when you have an odd number of teeth you introduce 'hunting' into the equation. It was very common on gear trains, for example the Norton Commando timing gears, to introduce an intermediate gear with an odd number of teeth. Known as a hunting tooth arrangement, it spread wear across all of teeth. Something you needed to aware of when lining up the timing marks, rotating the engine a few times, then trying to understand why your marks no longer lined up. The fact that the intermediate drive in this case is a 100/127 tooth combination, where the two gears have no relative motion between them, causes the mistiming.

 

[Screwdriver]

I think it has to be a multiple of 127 because you can't divide it down...

Your example proves the point. 100/127 gives you a 1.27 (or 0.7874...) relationship between say input/output. When do they next line up to a whole number.

Answer: only after 127 turns. There isn't any whole number (number of "turns") between 1 and 127 that brings the relationship back into synch.

 

[Mick Annick]

New grinder for finger callouses. Also good for abrading dirt out of your fingers. I needed to use the old one about 10 minutes after every climbing session, eventually wore out the motor, this has a bit more power to it.
Also comes with a razor blade skin peeler Nope. This bit will not be used.
View attachment 361442

https://www.amazon.co.uk/gp/aw/d/B09GXJKX9J

Rock climbing I assume? We’re in Corfe Castle this week, youngest and his wife are hanging off of Winspit at the moment…

 

[Maker]

New grinder for finger callouses. Also good for abrading dirt out of your fingers. I needed to use the old one about 10 minutes after every climbing session, eventually wore out the motor, this has a bit more power to it.
Also comes with a razor blade skin peeler Nope. This bit will not be used.
View attachment 361442

https://www.amazon.co.uk/gp/aw/d/B09GXJKX9J

What's wrong with a bit of sandpaper glued to the back of a hold brush?

 

[Kram]

Rock climbing I assume? We’re in Corfe Castle this week, youngest and his wife are hanging off of Winspit at the moment…

Id like to try Winspit one day, mostly indoors on plastic this year. Its a bit too far away.

What's wrong with a bit of sandpaper glued to the back of a hold brush?

The 10 minutes would turn into hours!
The resulting dust reminds me