Finishing the bottom of goblets

[benji79]

Hey guys,

I'm going ok with most of the goblets I'm making, but I just cant get a good finish on the base after parting it off. Ive tried hand sanding, drill press sanding and using a sharp tool to part it off.

Is there a trick anyone uses to finish the base?

Its ruining the whole piece by not being as smooth or clean as the rest of the goblet.

Any help greatly appreciated.

Benji.

[Skew ChiDAMN!!]

I try to leave myself about 1" of "waste" at the chuck end of a goblet specifically so I can make the parting cut fairly wide, thus allowing me access to the underside of the foot for a good finish before seperation.

This still leaves a little dimple from separating, of course, but a small sanding burr on a Dremel makes short work of that. :thyel:

Occasionally, no matter what I do the middle of the foot just doesn't look right when flattened like this. Sometimes cranky grain, sometimes just incompetence on my behalf. :shrug: Then, another "trick" I use is is to drill a small dia. hole in the centre of the foot and round over the edges with s/paper to make it into a conical dimple. This avoids the whole "not quite flat" issue altogether.

[powderpost]

Try this for a nice smooth bottom. :; As Skew said leave about an inch of waste. With the skew chisel on edge on the tool rest, and long point down, make a series of cuts similar to an axeman cutting a log. Turn the chisel handle towards the headstock so the bevel is parallel to the finished base and take light cuts. Leave a millimetre for a final cut. For the final cut slightly undercut the base so there is no 'pimple' left to make the goblet rock on a flat surface. Try this cut on a spindle first. It may be easier to remove most of the waste with a parting tool first, then finish off with the long point of the skew while the skew is on its edge on the tool rest. With the left hand under the goblet and fingers tips against the tool rest, It should just drop off in your hand. If you feel uncomfortable cutting all the way through, leave about 10mm and finish by hand.
Jim

[scooter]

<<<<beware -="" inexperienced="" advice="" related="" below=""> Beware - inexperienced advice related below >>> :D

I made a redgum coffee tamper the other day & used the skew to square the bottom & part off the top much as Jim has described.

The burnishing action of the bevel rubbing & the clean cut of the skew gave a great finish on the end grain.

The other idea that came to mind was a parting tool used at his turnfest a while back.

He had sharpened it much as one normally would, but did so at the edge of the grinding wheel, so it had a sort of spur on the edge of the point. He used this edge to cleanly part off the myrtle goblet he made on the day.


HTH..........cheers.............Sean</beware>

[powderpost]

Sorby produced a cutting off tool some time back. It was similar to a skew but was tapered across its width. The bottom edge had a groove machined in it and was sharpened by grinding and honing it square across the end, but at an angle similar to the skew chisel. It was supplied with a nylon sleeve for the bottom edge, to prevent it cutting grooves in the tool rest.
Jim

[scooter]

Gday Jim, have heard of those parting tools.

Occured to me you could make something that might work similarly with a standard parting tool by freehand grinding one bevel with the edge of either an angle grinder grinding disk or standard cutoff disk (not the 1mm tpe). Would result in a spur on either side of the tip of the tool, similar to the sorby tool.

Might try it with my CS parting tool for an experiment.


Cheers....................Sean

[Captain Chaos]

G'day Benji,
When turning goblets in the past, my method for finishing the base has been to leave about 1 inch of waste as Skew recommends. I then part a groove into the base at the length which will be the finished height of the goblet. The depth of the groove is about ¼", thus reducing the diameter by ½". I then remove the waste material to the left of the parting cut in order to allow me to cut into the base of the goblet at a slight angle, creating a slight hollow in the base. I usually begin the cut about ⅛" in from the outside Ø of the foot / base. I make sure that the parting tool is sharp before making this cut so that I get a good finish straight off the tool. I tend to part the goblet right off as Powderpost stated in his reply. " With the left hand under the goblet and fingers tips against the tool rest, It should just drop off in your hand. If you feel uncomfortable cutting all the way through, leave about 10mm and finish by hand.
Jim "
I clean any dimple etc off with a small hollow hand carving chisel & finish sand by hand.
Unfortunately I don't have any photos of my goblets to show what I mean. I tried to do a drawing in the Draw component of Open Office, without any luck at all.:no: Not the fault of the program, just me, I don't know how to use it yet.:doh:
Regards,
Barry

[joe greiner]

I haven't tried a customized parting tool, just use ordinary. Straight in to provide a support ring, like Barry, then at an angle to form the dished bottom. Excavate toward the chuck to provide working room. At about 4mm or so diameter, depending on the timber, I'm left with a somewhat ragged tenon-oid, which I cut off with a hand chisel. I like Skew's idea of a secondary dimple to erase the chisel work, maybe just use a countersink bit.

And just in case I don't catch the piece right, I fold a surplus bath towel on the lathe bed for cushioning.

Joe

[Gil Jones]

Benji, when I cannot use my Donut Chuck (or do not want to), I use this setup and it works fine. Hold the parted off piece by hand, and sand against the lathe powered sanding disc. Change Velcro backed disc/grit size as needed.

[dai sensei]

And if using all that good advise above doesn't work, you can always put on a felt base to hide it :U

[benji79]

And if using all that good advise above doesn't work, you can always put on a felt base to hide it :U

LOL :D , I like it..

Thanks for all the info guys, helped heaps.

Going to the woodworking show on Sat so ill be looking out for better tools then the el cheapos im using at the moment.

Hope to see a few of you there.

Benji.