Unkown thread.

I have some EMCO I/C tool holders and I want to get longer screws for adjusting the height of the block.

The screw is a Hex/skt grub screw. and has the following measurements which I cannot match to anything in my ref. books.

Dia. Imp. 0.193

Met. 4.91

Thread TPI matches UNF at 32 Tpi.

can anyone help identify this thread?

Clive

Sounds like #10-32 UNF might work, but .193" is on the large side of #10 OD spec. JD

It looks so suspiciously close to M5 (Coarse) x 0.8 = 31.75 TPI I'd be tempted to try that to see whether it fits.

Jon

Tried an M5 plug tap in the hole and no joy as the pitch is wrong. If I cannot find what it is I might tap it M5 and go from there as all I want to do is increase the length to give more adjustment as at the moment it holds only on the last 2 or 3 threads at the height I want.

I have UNF taps and dies but they do not fit either.

Clive

The toolholder is only hanging on by 2 or 3 threads,by doing this over a period has the thread in the in the holder been stretched or deformed? I would tap a M5 hole in an odd piece of steel and try the screw in it,though of course the screw could also be deformed, similar problems occur with the thread on Tee nuts and studs on milling machines

2BA ?

When I had an Emco the tool retaining screws were M5 x 0.8, can't really see it being anything other than metric as its Austrian.

Whats the machine ? have you asked on the Emco Yahoo user group?

Edited By JasonB on 14/01/2016 17:23:42

+1 for 2BA we stole BA from those alpine types

Neil

Clive

I have an Emco toolblock and holders but I don't recognise the number you quote, all of the toolholders I have use M8x.8 setscrews for tool height adjustment and tool locking in the holder.

I can load a picture if you want but they are on my w/shop computer and I'm in the warm !!!!

Emgee

Emcee do you mean M5x.8?

Silly question but is it a genuine Emco toolholder, a copy of an Emco one or just a generic toolholder that happens to fit this size machine?

Use a bit of care if you plan to tap the toolholders, I had to replace the height studs on some Dickson holders, very hard indeed! I made a D bit from a solid carbide drill shank to drill out the broken tap.

An interesting study so far, I know it is a genuine EMCO tool holder and tool holders as I removed it from an EMCO Maximat11 lathe and fitted a Schaublin type tool holder in it's place.

I have some fine thread metric taps and will check tomorrow to see if any match but the dia. being less than 5mm threw me a bit, not sure about 2BA it seems a bit course TPI. Also none of the Metric blades match when held against the thread but the 32 UNC blade does perfectly. But the tables of UNF do not match size wise and thats why I am checking here now to see if anyone knows different.

Agreed it is an Austrian make and I really cannot see why they would use an odd size thread at all. But then, who knows?

It may be something like the threads on rifle sights that match nothing I know of. I will report back again later.

Clive

Does it appear to be a 60 degree thread? You must have some serious magnifying kit with your background!

Neil

.

Clive,

I'm inclined to agree with Neil's latest advice.

• Many commercial Metric screws are a little undersize on diameter.
• The difference between 31.75 tpi and 32 tpi is pretty difficult to see.
• BUT the difference between 60° thread-form and 47.5° should be easy.

MichaelG.

Clive

My toolholders are Emco 5 size with M5x0.8 screws and take max 13mm sq tools, so your holders may be somewhat larger from the bigger lathe.

Emgee

Clive definately ask on the yahoo group its is for the larger Maximat, V10, V11, etc size machines

.

Clive,

Just a note of caution [Teaching Granny to suck eggs ?]

As you will see from the excellent diagram and notes here; It is possible to have a 'within spec' Tap which does not freely fit an existing 'within spec' female thread. ... The Devil is in the detail [that little white 'optional' area at the top of the diagram].

Assuming that it's an M5 x 0.8 Tap ... Have you tried using it as a thread gauge, laid against the grubscrew?

MichaelG.

.

Edit: [a useful Quote from the Wikipedia text; with my added emboldening] ... "Conversely, in an internal (female) thread (e.g., in a nut), the major and minor diameters are minimum dimensions, therefore the thread profile must end flat at D_min but may be rounded out beyond D_maj."

Edited By Michael Gilligan on 15/01/2016 09:48:58

OK, panic over as the 5 x 0.8 die runs the thread fine.

Thank you for your interest and thoughts.

Clive