Help!

[mike-bolton]

Newbe here just been turning a honey dipper out of a piece of greenwood (beech) around 30cm long all was going well I had finished the head if that's what's you call it but as i started thinning down the handle to about 1cm thickness I noticed it wasnt round but more squared I had no idea it was even possible to that on a lathe so I could use a bit of help please I'm confused I was also using a skew if that helps

Thanks any help appreciated :ho2

 

[Spindle]

Hi and Welcome

Sounds like the skew is bouncing / work is vibrating - try altering the approach angle of the skew or the speed of the lathe. Also try supporting the work by wrapping the fingers of your left hand loosely around the work as it guides the skew, (assuming you are right handed).

Also make sure you have as little tailstock pressure as possible.

Well done for having a go with the skew

Regards Mick

 

[mike-bolton]

Hi Mick

Thanks for the advice, now that you mention it I may have had the tailsock I bit tight. Also what speed would you suggest for something that thin.

 

[Spindle]

Hi

For something like a honey dipper I'd use around 2000 - 2500 RPM, if it started to whip I'd slow down a little at a time until it turned smoothly again.

Regards Mick

 

[mike-bolton]

Great I'll give that a go and hope for the best thanks again Mick

 

[CHJ]

To remove the uneven surface you can use a scraper in trailing mode, make sure you have the cutting edge under centre,* to remove the high spots.

Alternate is to use a flat block of wood with a piece of abrasive held against it to sand off the high spots.

Any attempt to use a gouge with a rubbing bevel will be difficult for you as a beginner as the gouge will more than likely just follow existing undulations.

* any tendency to catch throws scraper into fresh air, if it's above centre it will dig further in.

The faster you have it turning the less time there is for you to react and push the tool into the hollows which is a natural tendency for new turners not used to registering a tool securely on a rest.

 

[mike-bolton]

Well i tried again today but i used dry wood this time and a higher speed and less pressure on the tailstock as advised, there was some improvement but nothing significant. I have also noticed that the tailstock is a bit high off centre, could this be the cause? Anyway i managed to finish it off after some sanding

 

[Spindle]

Hi

The slight mis-alignment of the tail stock will not make any difference, (the work is still rotating around a fixed axis).

Have you tried the same exercise using a spindle gouge? do you get the same result?

When presenting the tool to the work try to be gentle and to not tense up - this will reduce the tools tendency to bounce

Regards Mick

 

[CHJ]

The finished item looks fine, how you achieved it is largely irrelevant to most viewers.

As spindle says, The tailstock alignment is within reason also irrelevant for between centres turning, a spinning piece of wood supported between centres will naturally form a true cylinder.

Tailstock centre alignment is only of critical importance when you try and drill or bore a hole with a drill or cutter mounted in the tailstock.

And then carrying out a centre kiss test is not necessarily an adequate test for alignment,* the important criteria is that both headstock and tailstock quill bores are aligned.

* you can have a tailstock pointing several degrees off left and right or (more unlikely) up and down and have the tailstock set up so the centres are touching.
If this is the case then the further away from the headstock your tailstock and drill is positioned and the greater the tailstock quill is extended from the tailstock the greater the effect of the alignment error will be.

 

[mike-bolton]

Hi

No I dont have a spindle gouge yet, I'm mainly using the roughing gouge and the skew that came with the lathe. But I've just order a 1/2" bowl gouge.

Like I said there's no problem when working on thicker pieces its just when I get down to around 1cm

The thing with the tailstock is when I prepare a blank for the chuck because its out of alignment after I create the tennon and mount it back on the chuck the live centre isn't centred so I can't support the work with the tailstock.

 

[Spindle]

Hi

It's not normal to drive spindle work with a chuck - usual practice is to use a drive centre in the headstock. The exception that springs to mind are goblets / hollow forms, but in this case it is normal to carry out the hollowing process before supporting with the tailstock.

When you mount your tenon in the chuck are you using the tailstock to align the work as you tighten the chuck?

How far out of alignment are your centres?

Regards Mick

 

[Phil Pascoe]

"a spinning piece of wood between two centres will naturally form a true cylinder"
That would only be true if the tool were parallel to the centres. There'd be no point in off centre turning if that were so.

 

[mike-bolton]

Hi,

I didnt use the chuck I turned between centres for the honey dipper.

But I plan on using the chuck for goblets and bowls when my bowl gouge arrives.

Normally when I'm using the chuck I turn the tennon to the exact thickness of the chuck jaws then tighten it up and then support it with the tailstock, but like I said it doesn't hit in the centre so I can't use it because its unstable.

 

[John. B]

Normally when I'm using the chuck I turn the tennon to the exact thickness of the chuck jaws then tighten it up and then support it with the tailstock, but like I said it doesn't hit in the centre so I can't use it because its unstable.

When making a tenon for a scroll chuck, you should open the jaws for about 5 or 6mm.

When a chuck is made the jaws are turned with that gap to make a true circle, so a tenon should be turned to that measurement to enable the jaw to grip the wood properly.

John. B

 

[mike-bolton]

Hi,

My scroll is 56mm so I usually turn my tenon anywhere over 60mm so there is a gap around the jaws.

 

[renderer01]

There is a point as you open chuck jaws from fully closed that the jaws form almost a perfect circle, this is the ideal diameter to cut the tenon but dont make the tenon so deep as it hits the back of the chuck jaws you need just a couple of mm clearance.
The other thing and yes well done for using the skew, but as your green wood reached 1 cm dia it may well have started to vibrate on and off the blade also the tailstock alignment can cause you to turn a slight cone or a grossly elongated flat spiral effect.
Make sure your skew is sharp and if your not sure how to do it get some assistance.
All best.

Rend.

 

[Spindle]

Hi

You still have not said by how much your centres are mis-aligned.

I think you may be 'expecting' too much with regard to work location. Wood has far more variables than metal and you can't really compare mounting the two.

Two very good points made earlier:

The work should not bear on the back of the chuck jaws, there should be a small gap
The tenon should be sized to suit the jaws at their ideal, (circular), gripping dimension.

Also the tenon should be identically profiled to the jaws, (dovetail / parallel etc.)

When you mount the work - bring up the tailstock and support it as you tighten the chuck - back off the tailstock, does the work still align with the tail centre? If not tap it gently to align it and the tighten again - repeat until it aligns. This procedure compensates for the variations in the woods density which can result in it not mounting true.

Regards Mick

 

[mike-bolton]

Hi,

Thanks for the replies, I dont know how much the tailstock is out, I'm not sure how you would measure it without some device?

I've been doing all of the above by not making the taper too deep so it sits on the base and leaving a gap around the jaws, so the only other thing I can try is like you said is set the tailstock up when I tighten the jaws up.

I'll give it a try tomorrow

 

[CHJ]

Dependant upon the wood sample you are using you may just be seeing the results of differing amounts of stock removal as you pass between cross grain and side grain. (think softer-harder in simplistic terms and cutter penetrating more)

On a larger diameter 1/2 a mm or so will not be very apparent but on your small diameter the effect may be more astute, especially if the differing grain density is biased to one side of the centreline of your spindle.

 

[Spindle]

I dont know how much the tailstock is out, I'm not sure how you would measure it without some device?

Hi

Carefully push the tailstock with a centre fitted up to meet a drive centre in the headstock. Lock the tail stock and see how far the two centre points are mis-aligned.

Regards Mick