How to turn rounded ends accurately?

[Evanism]

I'm turning up a great many spindles as very long mushrooms, think Shitake style. They are long, such as 200mm

The heads are obviously round. Im getting very favourable accuracy with the measurements and thicknesses. Once I part off both ends, how to I finish the top so it's spherical/rounded and smooth?

I've been doing it by hand on my big lathe disk sander, but there must be an easier way! I was thinking of a 125mm disk sander with an ultra-soft underpad. I just stuff the end in the middle and the conforming pad rounds it up...but this seems too technical.

Any idea friends?

(many thanks to for his past insistence on beads and coves, beads and coves, grasshopper!)

[Sawdust Maker]

I'll wait for 's words of wisdom

[Tim the Timber Turner]

How about driving the blank with in a chuck, backing off the tailstock, reducing the speed, and supporting the work with your left hand and part off leaving a small nib (3 to 4 mm) that could be hand sanded.

I find it much easier to get a good shape off the lathe, rather than try to blend it in on a disc sander.

This method requires a slightly longer blank to allow for the waste in the chuck.

I am assuming that your very long spindles are 200mm and not a misprint. (2000mm?).

Hope this helps

Cheers

Tim:)

[powderpost]

How about driving the blank with in a chuck, backing off the tailstock, reducing the speed, and supporting the work with your left hand and part off leaving a small nib (3 to 4 mm) that could be hand sanded.

I find it much easier to get a good shape off the lathe, rather than try to blend it in on a disc sander.

This method requires a slightly longer blank to allow for the waste in the chuck.

I am assuming that your very long spindles are 200mm and not a misprint. (2000mm?).

Hope this helps

Cheers

Tim:)
Assuming that 200mm is correct, I can agree with Tim, except that I would cut off completely with the long point of the skew. But then if the mushrooms are to stand on that end, shouldn't the end be square or even slightly under cut?
Jim

[issatree]

Hi Evanism,
I've watched Guilio Marcolongo turn Balls with a reasonably big Roughing Gouge, & I now do the same, & it works perfectly.
So you do the rounded end 1st. up, sand & finish. This is of course with no Tailstock.
I use 35 or 45mm. Spigot Jaws, that will hold at least 25mm. & not like the Bowl jaws that only hold approx.13mm.

I don't even own any 50mm. jaws now. Chucked 'em.

8 in. sticking out of my jaws are no problem at all. I wood turn them on close to 3000 RPM.
As for parting off, I use a 12 x 3mm. P&N Skew, with a pretty long Curved Bevel, & use the long point, so that you can get into small areas.

My Blade overall wood only be 4in. - 100mm. long.

[Jim Carroll]

As Lewis indicated either the Nova spigot jaws or the Vicmarc shark jaws are the way to hold the peice in the lathe for turning.

You just have to work the same as you would doing a goblet.

Turn the top end first and finish of then turn the thinner part next then the base.

Part of and sand the base.

[RETIRED]

What the rest said.:wink:

[Tim the Timber Turner]

As Lewis indicated either the Nova spigot jaws or the Vicmarc shark jaws are the way to hold the peice in the lathe for turning.

I'm going to disagree somewhat with Jim on this one.

I'm not going to say Shark or Spigot jaws are no good but using them instead of dovetail jaws puts the work further out (up to 40mm) from the bearings of the lathe and will increase vibrations.

This is a bigger problem when hollowing on a light duty lathe.

I have both types of jaws and seldom use the longer type.

In my experience a properly sized and shaped dovetail has as plenty of holding capacity.

For maximum holding power with dovetail jaws the dovetail needs to be just short of the jaw depth and with a shoulder on the work to make contact with the face of the jaws.

The chuck jaws should have a gap of 2 or 3mm when tightened onto the dovetail.

So I think you get a trade off, increased distance from the bearings using spigot jaws against less wood to metal contact using dovetail jaws.

That's been my experience.

Your mileage may vary.

Cheers

Tim:):)

[Jim Carroll]

Tim I agree to disagree

Properly shaped tenons are a must even with the shark jaws, and you still sit the peice flush on the face of the jaws.

I think for what Evan is doing there is no extra strain on the bearings as you ar only adding 15mm to the lengh of the peice.

Prefer the longer tenon just in case there is a catch and less chance of the tenon snapping of.

[Drillit]

Agree with Jim, whole heartedly. Drillit.




I'm turning up a great many spindles as very long mushrooms, think Shitake style. They are long, such as 200mm

The heads are obviously round. Im getting very favourable accuracy with the measurements and thicknesses. Once I part off both ends, how to I finish the top so it's spherical/rounded and smooth?

I've been doing it by hand on my big lathe disk sander, but there must be an easier way! I was thinking of a 125mm disk sander with an ultra-soft underpad. I just stuff the end in the middle and the conforming pad rounds it up...but this seems too technical.

Any idea friends?

(many thanks to for his past insistence on beads and coves, beads and coves, grasshopper!)

[steamingbill]

This one works for me.

Produces very nice spherical bobbles on the end of things ie chess pawns.

They would all be identical sizes with minimal effort.

I think it has potential to assist with shitake mushrooms.

http://www.woodworkforums.com/attachment.php?attachmentid=301326&d=1390132328

Bill

[issatree]

Hi Tim,
8 in. hanging out of 50mm. Jaws, wood certainly not be for me.
You wood be looking at Death in front of you.
There is no Vibration with Speed & a good P&N 25mm. Roughing Gouge.
Do you think I wood be silly enough, if it was going to come out, & to Print it so others could read it.
I really don't like putting my life on the line by using a set of 50mm. jaws doing that kind of work.
I Print, with 33yrs of Turning behind me, & Demoing in front of Turners better than me.

[DJ’s Timber]

Before we all go off tangent here and I must admit I'm leaning towards Tim's answer here.

Evan can you confirm that you're turning mushrooms end grain to end grain which is the grain running parallel to the bed of the lathe and between the headstock and tailstock?

[Evanism]

I'll try to get to all the questions....

They are 200mm long, the heads are 36mm and the stalks taper from 16mm to 12mm.

I was thinking about how things like chisel handles, cudgels, chess pieces or rolling pins are turned.

The wood is regular 90x45 pine from my most hated hardware retailer (cut to 45x45 in ~250 lengths) Knot free pieces are chosen with straight grain. They hate me there pulling apart 400 bits from the pile so I can find one that isn't Failure Grade.

I've turned them beautifully and now have the absolute hang of it. My template lets me get every curve to within a mm.

I need more sandpaper. Should have taken up that overstock I saw at one of the advertisers here.

No need for agro guys, I have most of the gear here except deep jaws. Ive been turning between a crowned steb and a good volcano-style live centre. (reminds me, I need a better steb). There is a nova chuck here with a few jaws, but all of them are for bowls....I think there might be some pin jaws, I'll take a dig tomorrow morning. Might need to order one Jim :)

Many thanks for all the ideas!

[Evanism]

This one works for me.

Produces very nice spherical bobbles on the end of things ie chess pawns.

They would all be identical sizes with minimal effort.

I think it has potential to assist with shitake mushrooms.

http://www.woodworkforums.com/attachment.php?attachmentid=301326&d=1390132328

Bill

I LOVE IT!!!!

[Tim the Timber Turner]

Hi Tim,
8 in. hanging out of 50mm. Jaws, wood certainly not be for me.
You wood be looking at Death in front of you.
There is no Vibration with Speed & a good P&N 25mm. Roughing Gouge.
Do you think I wood be silly enough, if it was going to come out, & to Print it so others could read it.
I really don't like putting my life on the line by using a set of 50mm. jaws doing that kind of work.
I Print, with 33yrs of Turning behind me, & Demoing in front of Turners better than me.

:oo: "Wow I didn't see that one coming":oo:

Issa mate I seem to have upset you. If I have I'm sorry. It was not my intention to upset anyone.

However I do think your post is somewhat of an over reaction.

Without trying to upset you further I will make a couple of comments .

I wonder how everyone did this sort of work before spigot jaws were available?

I did then, what I do now, I used dovetail jaws.

Finally, when I made my post I didn't expect everyone to agree with me.:no:

Cheers

Tim:)

[issatree]

Hi Tim,
My Apologies, I jumped the gun a bit.
Should not have wrote it that way.
Like I said I have seen Guilio do that a few times with the P&N Roughing Gouge.

Thanks DJ.