hollowing rig with a bit of power

[hughie]

I have a hollowing challenge on some very dry Acacia and it looks like some silica to keep it interesting. So I came up with this idea to remove the bulk and maybe finish it as well. I am using the new Arbotech cutter on a 4" grinder, nothing novel about this. But I have mounted it on a couple of articulated arms with height adjustment. The idea is I can swing across the bed and/or up and down the bed or in both directions for angle requirements.
Its fairly hefty as I didnt want vibration to be an issue, fearing the worst if got out of hand. The 12mm rods are the control handles.

[artme]

Ever the inventor Hughie!!! :2tsup::2tsup::2tsup:

You will let us know how it goes?:rolleyes:

[Sawdust Maker]

we need action shots :p

[dai sensei]

I assume, or hope, you don't intend using it with the lathe running?

Doesn't seem to be able to go too deep, unless clear of the grinder head dia wise. Interesting to see how it goes

[KBs PensNmore]

Nice bowl lathe, your own design? Can't see why it couldn't be used running, on a large platter. Could have used something like that a couple of weeks ago, 60 Redgum plates 190 X 35, sharpen, turn for 3 mins, sharpen turn for 3 mins, I now have a short bowl gouge if anyone wants one:D
Kryn

[rob streeper]

Hughie,

Love it, looks dangerous. I was thinking similar thoughts recently. My design incorporates a foot switch for the grinder to give a more rapid way to shut it down. What kind of body armor are you planning to wear?

Cheers,
Rob

[hughie]

Hughie,

Love it, looks dangerous. I was thinking similar thoughts recently. My design incorporates a foot switch for the grinder to give a more rapid way to shut it down. What kind of body armor are you planning to wear?

Cheers,
Rob

..at this point, speed :U

slow running lathe 100-150rpm

[hughie]

Nice bowl lathe, your own design? Can't see why it couldn't be used running, on a large platter. Could have used something like that a couple of weeks ago, 60 Redgum plates 190 X 35, sharpen, turn for 3 mins, sharpen turn for 3 mins, I now have a short bowl gouge if anyone wants one:D
Kryn


Kryn, I have some hard dry acacia and thought this might do the trick and I can empathize on the sharpening.

[rob streeper]

..at this point, speed :U

slow running lathe 100-150rpm

What do you think about one of those carbide burr discs for this kind of application? Like this http://saburr-tooth.com/toolsCarvingWheels.htm.

[hughie]

What do you think about one of those carbide burr discs for this kind of application? Like this http://saburr-tooth.com/toolsCarvingWheels.htm.

I have a couple on the other grinder. One of the reasons for going with the Arbotec is that it leaves a pretty good finish whereas the Saburr will require a decent amount of sanding. Other than that the Saburr are great tools and last a long time, cant fault them in that regard.

[Cliff Rogers]

I had thoughts of doing something similar, just haven't got to it yet.

I reckon the problem will be keeping the piece in the chuck. :think:

[Mobyturns]

I assume, or hope, you don't intend using it with the lathe running?

Doesn't seem to be able to go too deep, unless clear of the grinder head dia wise. Interesting to see how it goes

Hughie, I'm afraid I have similar thoughts to Neil.

One thing I noticed is the you have the cutting disc running from center to rim. Wouldn't it be better to face the other way cutting from rim to center. Less chance of major tear out & chips in the rim?? I also have concerns about the torque that would be generated on the support with the length of overhang from the edge of the grinding disc back to the pivot. I reckon those 12 mm rods are going to get bent very fast.

Not sure that 100 rpm would be slow enough for me.

[hughie]

Hughie, I'm afraid I have similar thoughts to Neil.

One thing I noticed is the you have the cutting disc running from center to rim. Wouldn't it be better to face the other way cutting from rim to center. Less chance of major tear out & chips in the rim?? I also have concerns about the torque that would be generated on the support with the length of overhang from the edge of the grinding disc back to the pivot. I reckon those 12 mm rods are going to get bent very fast.

Not sure that 100 rpm would be slow enough for me.

I can cut centre to rim by moving the cutter to the other side. The 12 mm rods are just handles to swing it around. Yeah speed is not where I would like it but physically I cant make it go much slower. So it will need a slow feed, mm by mm perhaps.

But I did give a thought to the angle or how the cutter is presented to the work piece, never really pursued to its logical conclusion. But had some advise from a well respected source on the phone the other day and I will be making a few small mods to the way the cutter is presented. This variation will allow me to use the Saburr cutters as well if needed so its a win win. Plus the feed and speed issue wont be that important.

[oreos40]

Nice set up! I dont think torque will be a concern. I have just a cutter mounted on a swing arm that is just 3/8" threaded rod and it works fine. I know a turner that has used a 4" grinder gorilla taped to a piece of pipe for hollowing out vases 5 feet deep! same proncipal as cutting large coves on the table saw. use common sense and dot get rushed. If you have the opportunity get some vid posted.