Toolholder Overhang

[NigeParticipant @nige81730]

I have been looking at options for a quick change type tool holder for my ML4 along the lines of the Chronos offerings. My query is about how much, if at all, the tool holder can overhang the limits of the compound slide it would be mounted on. I tried to make a simple drawing of my query which is in an obviously named album.

Though the main body of the tool post might be wholly supported by the compound slide it looks as if any tool holder that mounts to the post might overhang the compound slide 'footprint'. Is this normal and not something I should be worrying about ?

Thanks, Nige

[NigeParticipant @nige81730]

[Neil WyattModerator @neilwyatt]

My QCTP block is arranged so the outer edge of the dovetails align with the edges of the slide, so that' 1/4" overlap for a 1" wide toolholder, no apparent problems.

Neil

[Thor 🇳🇴Participant @thor]

Hi Nige,

On the QCTP on my 290 lathe the outer edge of the toolholder is about 10mm outside the topslide. As Neil says, no apperant problems.

Thor

[mechman48Participant @mechman48]

Hi Nige

I have my tool holder set back from the front edge of the compound slide so that the tool holder is over the main body of the slide thus offering more support…

George.

[NigeParticipant @nige81730]

Brilliant, thank you all, that clearly answers my question

Nige

[MuzzerParticipant @muzzer]

I'd say it depends what you want to do. You should always minimise the total overhand from the tool edge to the base of the top slide as a matter of practice but it's less critical for light cuts than it is for roughing and particularly parting off. I'd think that for an ML4 you need every opportunity to maximise rigidity. That also extends to making certain the gibs are well adjusted, particularly around the travel position where most cutting is done. As for whether the situation you sketched is OK, it may be fine, depending on the job and your approach to it.

My first lathe (Portass S) only had a single slide, so actually benefited from reasonable rigidity (it's all relative). It's something I've just replicated to some degree by eliminating the top slide on my Bantam. Time will tell if the loss of the topslide (only used for chamfering, threading etc) is a price worth paying for the resulting increase in rigidity.

Murray

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