Thread: Deep hollowing tools???

Originally Posted by HSS

Neil, I'd love to try out those tools and see how you're set up if that's ok. I'm down in Hindmarsh but I can come up anytime that suits you if that's alright. Likewise, if you're interested in what I'm up to you're welcome to check out the new workshop.

PM sent.
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Originally Posted by Cliff Rogers

Nice shed.

That would be one of the biggest understatements I think I've seen on the forum
but

Nice solution . I'm also thinking it's probably worth buying a normal lathe with variable speed to do all those smaller jobs on a more manageable platform.

By the way, the workshop isn't all mine, I share it with 3 mates. We've each got our own area from which to run our businesses. We all purchased a few pieces of machinery and pitched in doing the wiring, lighting etc. It meant we could afford good quality gear as we didn't have to buy it all individually. It's all second hand but in good nick and heavy duty.

I attached the handle of my hammer drill to one of the scrapers I was having trouble with and it works a treat. The cutting edge was overhanging a long way from the centreline (noted by Ern) and I just couldn't stop it catching and chattering uncontrollably. By using the additional handle and changing the angle of the tool I'm able to get a much better finish (so far about 150mm over the tool rest).

Another lathe is the best solution.

You can also use Vise grips for a handle as well.

HSS, if you like the option of using a side handle ( which I have been using for many years, when working freehand) you will absolutely love using a good quality hollowing rig. While free hand can have some advantages, using a jig is so,so much nicer.
Problem with most (not all) rigs is they are too limited in the way they hold the tools. Grub screws damage shafts and eventually your tool shafts look like the dog with TC teeth has chewed them.

When hollowing freehand on a fixed head lathe you really need to be standing on the otherside of the lathe bed ( with appropriately positioned stop switches etc) BUT with a hollowing rig you can stand in the usual spot and even fit a laser to help tell the thickness.

BUT this is still dependent on the right cutting tools.
I hope this helps

PS great set up!

In terms of reducing twisting torque, I mentioned modifying your shaft to make a swan neck, to keep the cutting edge on the main shaft centreline.

You can see what this this might look like if you follow Jim's links on p.1 of the thread.

This is good for oval or acorn shaped hollow forms when you need the 'kink' to clear a narrow entrance.

Inventor is right; grub screws are tedious and can do some damage. The Munro hollower handle however has a phenolic knob which is quick and convenient, and helps you orient your tool so that when hollowing blind you know where your cutting edge is. Obviously this wouldn't be hard to replicate.

Best of luck.

Having the usual bend/s in the shaft and the tip in line with the shaft work, up to a point. When you are hollowing on the sidewalls and under the very top of more of a 'square' or sphere shaped piece then it pretty much goes out the window. As you can't keep the tool rest and tool at the appropriate position/angle.
The answer is some sort of torque arresting.
I have found that when doing 'serious' hollowing ( deep and/or wide in burl etc) you need a lot of purchase on the tool shaft to prevent it from moving in the handle. One screw is not ideal. The best system I have found is the one Kelton uses the ER collets. Particularly now they are using the ER32 on their hollowing rig. A good collet system is the way to go. Compared to grub screws and even drill chucks etc. ( we all know how drill bit shafts look after the drill spins in the chuck)

Like most things it depends on how much you are doing and how serious you are.