Another new project... a QCTP (Quick Change Toolpost)

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AdeV:
Just a brief update today, I didn't get anywhere near as far as I wanted to :( Why is it the clock moves fastest between 6pm and 9pm? :scratch:

Anyway... Due to the unique way my boring bar is shaped (it came with the lathe), I have to send it into holes at quite a steep angle. So I can't bore the hole to full depth (about 3") in one continuous go, I have to take maybe 1/2", then I can get the tool a bit further in, and so on... Because of this, I need to know where to stop when deep in a hole (this would be true if I was taking the full depth in one go also); so an indicator is stuck to the swarf tray on its mag base:

When the indicator reaches zero, disengage feed, or suffer the consequences...

Here's the hole coming along. It's slow, tedious work. I like the mill better...

More tomorrow...

Brass_Machine:
Nice start to your project Ade! I am sure this will be as fantastic as your soon to be completed oil pan. :headbang:

Eric

AdeV:
Thanks Eric, I don't think it'll be quite as unique somehow, except maybe its size... It's a big boy...

Nothing done yesterday, work interrupted play. I got another 3 hours at it tonight:

The big hole is about 1" deep by 2.8" diameter. The inner hole could be anything, I haven't measured it yet. I will have to adjust the tooling setup before I can complete this hole to full depth:

As you can see, with the boring bar at full depth in the hole (around 2.2"), there's sod all room left before the tool that's on top of the boring bar hits the work piece, causing all kinds of aggro. It's this sort of stupidity that I'm looking forward to curing with the QCTP...

AdeV:
More boring...

Eventually(!):

That's 2.830" in diameter, and 2.725" deep. It's probably taken 9hrs to hollow it out.... I was planning to go to 3" diameter, but given how long it's taken to get this far, I may stay at 2.83" & simply make the eccentric a little smaller...

Of course, part of the problem may be my bizzare-looking boring bar. I've not seen anything ground like it anywhere else; it came with the lathe, and other than occasionally sharpening it, I've not changed its shape. Any thoughts gratefully welcomed:

Getting right into the corner of a hole isn't possible with this tool; if you cut straight in, then the bottom right edge cuts; if you angle it over sufficient to avoid that, then the top left part of the tool bangs into the back of the hole before the cutting edge....

andyf:
Hi Ade,

It probably started life more this sort of shape, so its shank could be set parallel to the lathe's axis, but repeated sharpening has removed the part outlined in red. I think it's time to raid the piggy bank and treat yourself to a new one.

Andy

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