Broaching unit for cnc lathe

Hi guys.
I'd like to built my own broaching unit but I can't figure it out how this unit on retract move "drops" a small amount to avoid rubing.

https://youtu.be/eIHbS_LGDOk


Any ideas? Drawings?

Thanks


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I think you will find what you are looking for here https://www.youtube.com/watch?v=vD9acXVdwew

James on the Clough42 channel did a series where be builds a spindle lock, broaching bit, and writes code to do the broaching. I've built all the hardware for my mill but haven't tried it yet.

Hi, not exactly.
I have done similar slotting already.
https://youtu.be/GxNd9NjNdDU

But I'd like to speed it up by using broaching unit like Benz LinA or other manufacturers. They are pricey. $$$$

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hy, check attached / does it ring a bell ? i can help you with more specifics, like a simple sketch, toolholder organs dimensioning, talking about your desired approach, crafting tips, whatever you wish / kindly :)

ps : drop amount has to be > turret radial feed among 1/2 M spindle turns multiplied by at least 20%, so to avoid friction even during high feeds; do the math :) this is why in that video, at 0:55, is said that max feed is 0.15mm/stroke, regardless of rpm value

ps2 : x+ M spindle trigonometic, x- M spindle clockwise ... or viceversa :)

Hi. Can you explain it, I don't get it.

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this is for the "drop" behaviour; imagine such a cam, with the profile from the image from my previous post; the axis of this cam is coaxial with the M spindle

Cylindrical Cam - YouTube

Do you know if the reciprocating action is made by conrod? have you seen one stripped? Have pictures maybe? Or could you sketch internal bits.
Watched that cam video but still don't know how that works.

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Do you know if the reciprocating action is made by conrod?

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hy :) what do you mean by "reciprocating" ? what is a conrod ?

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have you seen one stripped?

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no, but i have watched a few videos with different types of constructions

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Have pictures maybe?

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pls check attached : is a rough "kinematic chain"

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Or could you sketch internal bits.

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it will take me a while, in order to draw a functional type / kindly :)

yes, z movement is done by a mechanism similar to a conrod :)