Hole in tool post

[The Real Ron SkingleyParticipant @therealronskingley]

Hello All,

Discovered I have a quick-change tool post.
And it's got a purposeful looking hole in one corner.
But no idea what it's for.
And ideas please?

(Now let's see if I can upload a pic).

[The Real Ron SkingleyParticipant @therealronskingley]

What’s it for

[GavlarParticipant @gavlar]

It's for a pin that locates in the compound slide, presumably to prevent the toolpost moving under load.

[Paul LousickParticipant @paullousick59116]

"It's for a pin that locates in the compound slide, presumably to prevent the toolpost moving under load"

Or possibly to lock it in a square position and not rotated.

[Mike HurleyParticipant @mikehurley60381]

Posted by Gavlar on 10/09/2021 13:03:37:

It's for a pin that locates in the compound slide, presumably to prevent the toolpost moving under load.

I've got exactly the same model ( RDG? ) and it doesn't align with the corresponding detent hole in my compound. To be fair, I think it is sold as ' for Myford and similar size machines ' maybe it does align on Myfords specifically? ( Mine's not a Myford ) I have always thought it might be an alignment hole for a pin when manufacturing?

[The Real Ron SkingleyParticipant @therealronskingley]

Thanks chaps.

Both good ideas.
Unfortunately, from a practical angle, my topslide has a different dia. hole (bigger) that is square on to the centre post, on the chuck side.
So it would have the tool post facing towards the tailstock at 45 degrees.
But that's just my lathe (an ageing BV20).

[The Real Ron SkingleyParticipant @therealronskingley]

Posted by Mike Hurley on 10/09/2021 13:22:43:

Posted by Gavlar on 10/09/2021 13:03:37:

It's for a pin that locates in the compound slide, presumably to prevent the toolpost moving under load.

I've got exactly the same model ( RDG? ) and it doesn't align with the corresponding detent hole in my compound. To be fair, I think it is sold as ' for Myford and similar size machines ' maybe it does align on Myfords specifically? ( Mine's not a Myford ) I have always thought it might be an alignment hole for a pin when manufacturing?

Ah yes, could well be a manufacturing alignment hole.
Anyone here have a lathe that it would align with?

[Mike HurleyParticipant @mikehurley60381]

Co-incidence or what. The non myford lathe that I've got is an ageing BV20! So I have exactly the same issue. Never come across anyone with one of these before – is yours the version with the gearbox for speed changing or the belts version? If the gearbox one I assume you also own a pair of substantial ear defenders?

Mike

[The Real Ron SkingleyParticipant @therealronskingley]

Just as a general comment, in case anyone's wondering.
I'm getting back into model engineering after a 5 year apprenticeship, my Dad being well into it, and after he passed away my Stepfather too.
Then many decades spent in electronics and software, retired now, collected a bunch of tools and this lathe, then my wife passed away about 5 years ago.
And only just picking it all up again.
So I'm 'discovering' things I had forgotten I had, or forgotten why I bought them.
Currently working on a Stuart Victoria.

[The Real Ron SkingleyParticipant @therealronskingley]

Ha ha, yes Mike it's the geared version.
Bought from Axminster (complete with Axminster plastered all over) and minus a faceplate 'cos it was cheap and the last of it's type being sold by them.

[The Real Ron SkingleyParticipant @therealronskingley]

The lack of a faceplate is causing real problems trying to machine the Victoria flywheel. But that's another story.

[Mike HurleyParticipant @mikehurley60381]

What area are you from? If local ish you can borrow on of my faceplates no problem ( i'm in the West Midlands )

regards

[The Real Ron SkingleyParticipant @therealronskingley]

Thanks for the offer Mike, but I'm in SW Ireland.

[Michael GilliganParticipant @michaelgilligan61133]

On the original Dickson tool-posts, a hole was intended for an alignment pin.

The purpose of any ‘similar’ hole on a ‘clone’ is still open to question.

MichaelG.

.

Ref: http://www.lathes.co.uk/latheparts/page13.html

Edit: __ as a slight digression: The patent for a tool-setting fixture is worth a look:

https://worldwide.espacenet.com/patent/search?q=pn%3DGB1215583A

Edited By Michael Gilligan on 10/09/2021 13:57:27

[The Real Ron SkingleyParticipant @therealronskingley]

Ah yes, thanks. The Dickson one has the pin square-on which would make sense.

[John HaineParticipant @johnhaine32865]

Yes it's for a locking pin, and no there isn't normally a hole drilled for it on the topslide since lathe and toolpost are from separate suppliers. You have to drill your own hole in your topslide to fit..

I gave up using the topslide on my Myford as it's tool flimsy and tapers are done with the CNC. I made a block to fit the cross slide to support the QCTP and drilled it for a dowel pin as I want to get precise re-registration of tools when removed/replaced – without a pin the TP will move if even a tiny bit, for example when parting.

[The Real Ron SkingleyParticipant @therealronskingley]

That's a good idea.
Can't give up using my topslide though as the main saddle drive handle is way too clunky.
Might look more closely though at making a hole somehow.
Hmmm…

[The Real Ron SkingleyParticipant @therealronskingley]

Posted by Michael Gilligan on 10/09/2021 13:49:56:

On the original Dickson tool-posts, a hole was intended for an alignment pin.

The purpose of any ‘similar’ hole on a ‘clone’ is still open to question.

MichaelG.

.

Ref: **LINK**

Edit: __ as a slight digression: The patent for a tool-setting fixture is worth a look:

**LINK**

Edited By Michael Gilligan on 10/09/2021 13:57:27

Patent makes interesting reading.
Set the tool up on a jig with a dial gauge, and transfer to the lathe.

[Mike HurleyParticipant @mikehurley60381]

Thanks Michael & John for clarifying things – the info on Lathes.co was particularly useful!

I'll look into getting a suitable locking fitting knocked up as I have had a few toolpost ' slippage ' issues in the past!

regards Mike

[The Real Ron SkingleyParticipant @therealronskingley]

Yes, thanks all.
I will also look at making up perhaps a plate with a pin to engage the existing hole in the topslide, and a hole to take a pin from the toolpost.
Maybe

[JasonBModerator @jasonb]

Victoria flywheel should be OK held with a 4 jaw gripping inside the rim. I hardly ever use a faceplate for turning flywheels finding the 4-jaw much better.

[The Real Ron SkingleyParticipant @therealronskingley]

Yep.

But my 4 jaw won't reach, it's too small.
Sad.

[old martParticipant @oldmart]

The alignment of the toolpost matters most if you are using a parting off tool which must be at right angles to the spindle axis. For most home use having exact location is optional as long as the toolpost can be tightened securely.

John Haine's toolpost mod is the neatest and stiffest that I have seen, and it can be removed quickly if the compound is needed for a specific job.

[DiogenesIIParticipant @diogenesii]

Faceplates.. ..Just on the off-chance, you might as well give us the the spindle nose / flange dimensions.. ..even if nothing used turns up, you might at least find out if something new can still be obtained..?

[Mike PooleParticipant @mikepoole82104]

The hole in question has often had a pin with a knurled end on some of the lathes I have encountered. If using it as a setting aid then the fit of the tool post to the fixing bolt will need to be checked.

Mike

[Author]

Posts