Thread: Lathe Help

Thanks Ewan. I can see the magnet but not where the pickup is located. What lathe is that? Is it a Hercus 9"?

Setup looks a bit similar to mine with the belts etc.

Hi Ed,
It is a Mars lathe, like a hercus only a bit bigger. My sensor is just a hall effect sensor on a tiny PCB with a pull up resister and dipped in epoxy. Its only about the size of my thumbnail. I can't seem to find a photo of one anywhere.

Ew

Found one, https://www.woodworkforums.com/showth...26#post1553326

Thanks Ueee, seems like your back gear clearance is way more than mine. I will see how mine goes for the short term and look to move to a better location once I can think of a better mounting location.

Despite still needing to get a few critical parts (rest of the gears off pipeclay, tailstock clamping arm, a few other bits) the last of my critical parts came in today from CDCO. Playing around for a few moments it seems like a massive improvement over the original tool holder I had.

AXA wedge toolpost:



Playing around with the parting blade holder I have a question:



The parting blade is tapered. Can I use this in the holder I have? The holder seems to be square rather than accommodating the taper on the blade.

Lastly I need to get the t nut milled, fingers crossed my bud with his mill is on hand for that:

Hi,

Can't help you with the parting blade, I use a carbide insert. It's always scary parting off in a hercus lathe.

I reckon that toolholder will be hardened. If your mate can't help you, I can do it at work. I'm at Wattle Grove near Liverpool.

Ben.

Thanks Ben, appreciate the offer of help on the t nut.

What's scary about parting off on a hercus?

I've got a 260, great little machine. But when it comes to parting off it scares me every time. It's just not rigid enough I guess. I am using a carbide insert cutting, 2mm thick, probably not really the best for the lathe. I've never tried using a HSS blade on it yet - but will get around to it (one day).

Ben

The T-nut blank isn't hardened. Very quick and easy job on a mill, should only take a few minutes.

Regarding the tapered parting blade, yes that's fine in your holder. That taper is side relief for the plunging cutting nature of the tool. The trick is to have the blade only extending from the tool enough to get the job done. You have to watch that the centre height changes a little as you move the tool in and out in the holder so if you adjust the blade check the height on centre and adjust if needed.

Parting off in a Hercus is a bit hairy/nervous for me too, as you say I think it really comes down to rigidity. The thicker the piece the more scary, I guess because the thicker the piece the more critical flex is and if it flexes it gets you into trouble. I've had a few whoop's where something has shifted or flexed and I've jammed the blade and stalled the lathe, but I haven't bent or broken anything - that might be the benefit of a belt driven lathe (not sure what a geared head lathe would have done?), but the workpiece has come away with a few scars .

Really pays to tighten any gibs, clear chips often and use plenty of lube. I'll cut and retract, clear and go again. While its cutting good I'll keep going but I can usually feel when things are starting to get iffy. Sometimes parting off a little more aggressively works better but it depends on a few factors.

Thanks hornet, I knew the edge was for relief which was why I was asking if it was a problem putting it hard up against that edge as that would effectively remove the relief on one side and make it greater on the other side.

Thankfully the QCTP makes it very easyto adjust tool height so I will keep an eye on that too.

I've heard that heavy cutting and a VFD do wonders for parting off on the Hercus. You can get a good cut going and increase the speed as it nears the centre.

I will be practicing on some scrap to get the feel before I go at it on some work for real.

I have used the same parting tool holder, i just sit the bottom out from the side a little to keep the side clearance even on both sides.
Try to part off right up near the chuck and don't use a live center. It will cause the cut to pinch the blade if the work flexes. A rear mount parting tool (upside down) should fix a litt of the issues.

If you have a bad moment with a HSS partng tool on a geared lathe either the part bends or the blade breaks, or should i say explodes into several pieces.

Ew

Originally Posted by Ueee

I have used the same parting tool holder, i just sit the bottom out from the side a little to keep the side clearance even on both sides.

I'll do that, cheers Ueee

Originally Posted by neevo

The parting blade is tapered. Can I use this in the holder I have?

Yes, just shim the bottom out so the blade sits vertically in the holder.
Cheers

So today I managed to steal a few moments to put my cheapie eBay switches etc into my equally cheap eBay waterproof box.

It is designed to control a VFD setup once I get a 3 phase motor. I wanted to keep it clean, simple and only really have a switch, kill switch, speed controller and rpm display.

Pretty happy with how it turned out: