Split turning?

[rsser]

The missus want two lengths of half moon x-section wood to use for ironing seams flat in the sewing she does, so this is a job for her birthday pressie. Each would be 2" diam.

Reading up on split turning it seems like the thing is to glue two flat blanks together with newspaper or brown paper in the middle.

It'll have to be hardwood to take the heat.

My concern is what happens when you centre the laminated blank and crank the pressure up.

I've got a cup centre for the tailstock but the drive dog pin will have to go in a bit for the spurs to engage.

Should I be wearing full protective gear? :oo:

It won't actually matter that much if I offset the centres a bit since a bit of taper won't worry her but I think I'd notice every time I saw them :(

[Robomanic]

Could you pre-drill the centre point to take the strain out of the spur drive but still give enough to locate and center it? Do you have a spur drive with the ring of small teeth rather then four large ones? Their centers are spring loaded.

The last split turning I did was four pieces of spotty gum glued up as quarters. I was not happy with the glue and had similar concerns about wedging them apart with the spur drive i had at the time so I nailed a piece of sacrificial ply to both ends and drove through that.
It was all in vein because half way to making it round I had the worst skew catch I have ever had and the assembly parted company from the lathe and each other. One hit my arm and face shield, one put a solid dent in the corrugated iron wall behind the lathe and by that point I didnt really care were the other two were....

Got them all together and found I had dug in after exposing a gum pocket. Sharper chisels, smaller cuts, more respect from that point on but never finished that project.

You'll be fine :)

[bellyup]

G'day Ern,
What about a worm-drive clamp around the timber at each end?
Bruce.

[gtwilkins]

I do the same thing with involute turning, just hot glue a block of plywood on each end to stop splitting the glue line.

I now turn simple shapes like this just with duct tape at the ends to hold the blanks together (hot glued to the plywood block) and then tape the center after shaping it and then shape the ends.

I also quite often use a dead center as the driver instead of the spur center.

If you don't want a full semi-circle put a third blank in the center so you get an arc on the outside pieces.

Trevor

[rsser]

Thanks guys. Good tips. Hose clamp sounds like good insurance. And yes, a Steb centre might deal with the headstock end.

Shannon, ouch!

Good to hear from you again.

[Robomanic]

Another thought...
Maybe a sacrificial rectangular piece down the middle with the two pieces you will keep glued each side? Would not give you half round sections but would a flatter final section help anyway?

[Robomanic]

haha slow typing there by me didnt see you had responded.

Good to be back Ern. The last 18 months have been pretty crazy with work and our new addition. Liam is 7 months old now which I find very hard to believe sometimes.

[rsser]

Ah, congratulations.

Yes, even harder when they're young adults prospering in their own fields.

My eldest just clocked up his millionth dollar in project grants. Reckon my head is bigger than his :-

Apologies for the minor 'dad' gloat.

[Robomanic]

Thanks, yeah I bet it is.

I gloat too - but for now it is mainly about nappy weight and getting through a feeding without anything on the bib :D

I handed him a toy screw driver a couple of weeks ago, which was followed by a disgusted look and he quickly dropped it. Didn't even try to eat it....

OK hijack over :)

[robert brown]

Hi ern. If you dont mind small nail holes on the end .....i usualy nail a disc of plywood on the ends..it works for me...

Robert.

[rsser]

Yeah, I offered to shout the other son a shared weekend learning with Vic Wood and he declined.

Regret it but what can you do?

Just offer them opportunities and see what grabs their interest.

So this is 'split turning' in a metaphorical sense so maybe we're still on topic ;-}

[rsser]

Thanks Robert. Seems we were typing at the same time.

Another method of insurance.

As it's not a corbel, if that's the right term, I can sacrifice ends on the bandsaw.

[RETIRED]

You can borrow my cone centres if you want 'em.

You didn't say how long they were.

[sjm]

My understanding is you want to split a cylinder in half, length-ways. If that's the case, why not just turn it solid, without laminating anything, then run it through the band saw? What am I missing here?

[Sawdust Maker]

Ern

interesting
2", isn't that the same size as standard chuck jaws?
chuck jaws one end, cone at the other?

slice end off with saw, if square

My boss does a lot of sewing so am mighty interested in how they are used - also in how long they are
I'm always on the look out for anything I can make on the lathe etc to make the sewing go easier.

[RETIRED]

I'm always on the look out for anything I can make on the lathe etc to make the sewing go easier.And to score Brownie points?:wink:

[RETIRED]

My understanding is you want to split a cylinder in half, length-ways. If that's the case, why not just turn it solid, without laminating anything, then run it through the band saw? What am I missing here?Sometimes it is easier to turn the article in " halves".

On some turnings you cannot cut them with a saw because you have no support unless you build a sacrificial sled.

This is the way we do verandah posts (sled) but smaller article like corbels we used to turn them in 2 halves.

[Sawdust Maker]

And to score Brownie points?:wink:


Too true :D

[joe greiner]

Back on topic:

The hose clamps and cone center work best if the piece is already round - a chicken or egg problem.

If built up from rectangular stock, I'd make the blank extra long with wood screws reinforcing the glue attachment in the end regions. No need for exotic centers. Turn the target region, and cut off the ends.

Cheers,
Joe

[RETIRED]

cone center work best if the piece is already round - a chicken or egg problem.Not the cones we have Joe.:wink:

We used to do all our balusters in these.

[Skew ChiDAMN!!]

Occasionally I've done similar, small split turnings for fascia pieces. (half-columns, etc.)

I use rectangular stock a bit over twice the length I want, screwed together in the middle. That way I can turn both ends (the 2nd end being in case I stuff up the beads/coves on the first... as is my wont. :doh:) and the middle, square section makes it easy to cut on the BS. ie. they remove the need for wedges or a cradle to prevent it rolling.

[chuck1]

hi if your going to do a paper join the last time i did one i used drawing / art paper as the job will come apart easier! news paper is to thin!

[rsser]

Thanks for all the tips guys. Good stuff.

Chuck, I did wonder about that; thanks.

, they'll be 60cm long, and thanks, I have a cone from the Nova tail centre kit and will check the size.

Nick, they're to raise the seam to allow better ironing. Seems (cough) that just using an ordinary ironing board means the seam gets pressed into the padding and the result is not up to par. At least this is what I recall from the conversation when most of the brain was thinking about the turning side of it.

Yes, the piece could be chucked. Splitting the halves might do some damage so leaving some waste would be a good idea anyway. On the other hand the two blanks would have to be the same size.

[Robomanic]

hi if your going to do a paper join the last time i did one i used drawing / art paper as the job will come apart easier! news paper is to thin!

I would agree there Chuck, I have had joins with newspaper where the glue went right through and met in the middle. Might as well have glued it without the paper.

The drawing art paper you mention, is that the thick embossed kind as used for charcol sketching?

I have used regular 80gsm A4 printer paper many times with PVA. Seems to be thick enough that the glue does not soak through, but tough enough that if abused it holds on. It is what I had used in my earlier tale, but it failed because the four pieces where not square in cross section or very straight so there was little area actualy in contact between them.

I will be very interested to see the finished product Ern, good luck with it and pls post some pics.

[rsser]

Copy paper and yellow glue I have.

Brown paper comes in various weights; have a roll of 'craft paper' from Officeworks which is pretty thin.

The only stock I have in 60 cm+ lengths is redgum. That's always a bit of a lottery but there's plenty of it. Buggered if I want to go down to the wood merchant and pay for some 'Tassie Oak'.

So first shot will be a Steb centre to drive it and cup centre at tailstock end. I can't be fagged equally sizing two blanks to glue together. The cup centre should hold the tail end together and the Steb distribute the drive forces.

And maybe I'll put on the motorbike leathers and helmet when roughing down ;-}

Happy to post some pics Shannon.

This is shaping up design-wise as interesting as the froe maul I made for a forum member a while ago. Haven't heard from him since. Hope no news = good news.

[Woodwould]

I've made many split turnings such as 12" long x Ø3/4" longcase clock columns and 36" long x Ø2-1/2" quarter columns for chests etc. The way I do it is to just glue the segments together with horse sauce, leaving the last inch or so un-glued.

After turning to shape, I slip a pallet knife into the seam in the un-glued end and apply a little heat from a hot air gun. By gently prying and heating, the segments come apart quickly and a wipe down with a hot cloth removes all traces of glue.

I do have a Steb centre now, but the last split turnings I made were done with the old standard four-blade drive which I belted into the end of the blank as per normal.

[rsser]

That's clever; saves you having to scrape or plane yellow glue off.

Time to dust off the beads.

[rsser]

So, update.

Lost the lottery.

The good length of redgum that Calm had kindly given me, salvaged fence railings from a stud farm IIRC, had the cranky grain you'd kill for with a pepper grinder or the like, and kill with for my purposes.

Sized it to 6cm square, ripped it down the middle, and then set to with a plane to flatten the glue faces.

Damned if I've seen such a poor result before.

62* cutting angle, close mouth, freshly sharpened A2 blade ... and the tear out was chronic.

Seems it's off to the wood merchant with tail tween legs.

Anyway, Nick to come back to your question, it's called a seam roll, and what it does is allow the seamstress to iron a seam without the seam allowance showing on the outside. Esp. handy with a sleeve eg. when otherwise you'd be ironing 4 layers of fabric.

And I thought I was fussy about finishing.

[chuck1]

I would agree there Chuck, I have had joins with newspaper where the glue went right through and met in the middle. Might as well have glued it without the paper.

The drawing art paper you mention, is that the thick embossed kind as used for charcol sketching?

I have used regular 80gsm A4 printer paper many times with PVA. Seems to be thick enough that the glue does not soak through, but tough enough that if abused it holds on. It is what I had used in my earlier tale, but it failed because the four pieces where not square in cross section or very straight so there was little area actualy in contact between them.

I will be very interested to see the finished product Ern, good luck with it and pls post some pics.
its the same paper i draw on not sure specifications it cost me $10 for a book of it 50 pages . it spilts really well, i did a turning job for a friend doing foundry it needed to be in half and doweled to join back together ill try grt a photo of it!

[Sawdust Maker]

...

Anyway, Nick to come back to your question, it's called a seam roll, and what it does is allow the seamstress to iron a seam without the seam allowance showing on the outside. Esp. handy with a sleeve eg. when otherwise you'd be ironing 4 layers of fabric.

And I thought I was fussy about finishing.

Bad luck with the wood :doh:

Yeah, I asked the boss whom pointed the the things she uses :doh::C

But I'd like to see the finished item when done pls

[Skew ChiDAMN!!]

Sized it to 6cm square, ripped it down the middle, and then set to with a plane to flatten the glue faces.

Damned if I've seen such a poor result before.

Say what? :o

You should know from the lathe that cranky redgum - although it can be beautiful - is called "cranky" for a damned good reason. Sharp tools, your best technique and it's still a mongrel to finish...

And you hit it with a plane? :U


Ah well, 'tis only wood. Here's hoping you have better luck in Round 2. :;

[chuck1]

I would agree there Chuck, I have had joins with newspaper where the glue went right through and met in the middle. Might as well have glued it without the paper.

The drawing art paper you mention, is that the thick embossed kind as used for charcol sketching?

I have used regular 80gsm A4 printer paper many times with PVA. Seems to be thick enough that the glue does not soak through, but tough enough that if abused it holds on. It is what I had used in my earlier tale, but it failed because the four pieces where not square in cross section or very straight so there was little area actualy in contact between them.

I will be very interested to see the finished product Ern, good luck with it and pls post some pics.
i use 110gsm art paper even a touch thicker but 110 works well!

[rsser]

Thanks Skew.

This stuff had 180* grain reversal in the diameter of a peanut!

Cranky's fine. This was psychotic.

Anyway, I had a length of real mahogany in the shed. And it is the missus' 60th. And she does make me some great flannel shirts :D

So to oblige Robomaniac here's the start of the WIP.

Following WW's advice on using horse sauce*, not having a glue pot I added 35g of pearl with 35ml of water and got it melting on a double boiler in the kitchen. Used one of those new fangled thermomo thingies that measure the surface by infrared something or other.

Dunno why Neil says the odour may be offensive.

Smelled just like the veal shanks I boil up for soup stock.

In fact, Neil, this could save me some time. If horse sauce is 'food safe' :rolleyes:

Any case, I added 50mm to the length for docking and 5mm to the radius in case of err, nah, not going to say it.

Wash up (oh, yeah, that's still to be done before the missus gets home):

Once the goo was spread and clamped, the glue was cooling fast so my ends aren't flush. Glad there's some docking margin. And I've got my doubts about the face match so may add a few turns of tape when on the lathe just for insurance.

Next time I'll add a bit more water to the sauce.

Turning details later.

* Horse sauce (http://www.ubeaut.com.au/hide.htm)
.

[Woodwould]

Good for you Ern! You don't require clamps with HS, but you're excused as it's your first encounter with the stuff.

[rsser]

LOL.

Neil's sheet said 'maybe' with the clamps, and given the rate the thing will be spinning ...

But the sauce is fun. Messy for a one-off, but cheap, simple and reversible.

[rsser]

Update:

The Steb centre and the cup centre at the other end worked fine though I crept up to speed to begin with :rolleyes: The mahogany was fairly soft and both centres got a good bite without much wedge effect. Helped by the gap at the ends created by the absence of 'sauce'.

Pic 1: truing up
Pic 2: diameter sized every few inches for the length of the piece
Pic 3: sanded.

The critical part is flatness and I sanded with a cork block to help.

There's a couple of mm of variation so it will go to the birthday girl for inspection before the turning is split with a hot knife as per WW's instructions.

[Woodwould]

There's a couple of mm of variation so it will go to the birthday girl for inspection before the turning is split with a hot knife as per WW's instructions.

Cold knife, used as a froe, and a hot air gun to soften the glue.

[rsser]

OK, thanks.

The piece is 50mm thick .... ?

[Woodwould]

Try it, you'll be surprised.

[rsser]

OK, thanks again.

My palette knife is pretty small. Don't know what you meant by pallet knife, but perhaps the putty knife in the pic above will do?

[Woodwould]

Any blade that you can insert in the split and apply leverage will do. I have a selection of pallet knives from thin flexible artist's jobbies up to ones capable for clefting firewood in twain.

[RETIRED]

ones capable for clefting firewood in twain.Do you call that an axe?:D

[Woodwould]

It's more of a burger flipping device, but feel free to tackle a pile of Red Gum with it if you like! :roll:

[Robomanic]

Very interesting so far Ern.

[rsser]

Thanks.

Well the flatness met with a query about performance under the full length of an iron so it was back to the lathe.

Two lights on the backside, straight edge across the top; marked two high points and took them off with abrasive sheet on the cork block.

Then got closer with one wrap of abrasive for each grit on the straight edge (steel, flat on every face).

Time to get out the froe, burger flipper, log splitter ....

The wood's soft; hope under heat the glue's softer. OK WW ... I'm with the program ;-}

[Sawdust Maker]

mega brownie points in this one :2tsup:

[Woodwould]

Time to get out the froe, burger flipper, log splitter ....

The wood's soft; hope under heat the glue's softer. OK WW ... I'm with the program ;-}

Just take it steady and let the heat do its work.

[rsser]

Update:

Just had at the split with a putty knife. Got in 50mm or so and coudn't get further.

From the other end, a bit of resistance and then 'split'.

Brilliant.

Almost all of the glue is on one side (no surprise) and I'll need to take care to get it off cleanly with a hot rag.

Wouldn't want to pollute the ironing surface with unwanted 'aromatics' :rolleyes: Don't think saying 'Yes dear, but you're still just a filly' will cut it any more :wink:

She's pleasantly surprised that she'll get two of them :doh:

Thanks all for your sage advice.

[Skew ChiDAMN!!]

What was your line...? :think:

Ah, yes. "No pix, it didn't happen." :U

You can't just use a scraper on the glue?

[Woodwould]

Proper stuff! :thyel:

[rsser]

Skew, pics in the morning (damn your memory!). Tonight's the romantic dinner out. Of course the bits will be taken for her final approval. LOL.

Thanks WW; that's high praise :-

[Sawdust Maker]

Yeah

get any of that glue on the serious side and you will be in trouble for quite some time.

a few dinners out might rectify such a lapse - should take a few years though :doh:

[rsser]

Yep. You can imagine the response first time around; and it's a birthday pressie. And the day is a biggie.

Soo, Skew, scraping is a poss'y, yes, but the glue faces need to end up flat to sit on the ironing board; and they're jointed already. The mahog is softish and I don't have much scraping practice. And don't know how to hold a half safely without damage.

Hot rag and care is option 1. Will think of reasons for whatever option 2 might be while I sleep.

Meantime a really good dinner has been had and H. was pleased with the feel of it.

So, dock ends and remove glue and dull the edges tomorrow.

Reconstructed pics attached while I'm still buzzing from too many cafe corretos. Grappa ain't what it used to be :no:

[Woodwould]

Ern, next time use thinner glue on both surfaces and rub them together before the glue cools. You will achieve a better bond for turning and parting will be easier too.

[oldiephred]

With all the good ideas , you really don't need more ---- however---. I do a fair amount of this type turning and I never glue the areas that will be finished pieces. I cut the rough stock long, glue the ends only and secure them together with a wood screw. When done, cut the ends off.

[rsser]

Thanks for the advice gents.

[rsser]

So the wash-up, literally, is this:

As WW noticed and as I wondered about earlier, the glue was too thick.

Upside is that one half needed the min. of cleaning and had a bow tied on it and left for the birthday gal to discover (while I b*ggered off back to the country).

Other side, the one loaded with the 'sauce', took a Scotchbrite and more effort than time allowed to clean up properly.

Just as a BTW, WW, I seem to recall you can hit the dried sauce with meths. Just makes it brittle? No advantage?

[Woodwould]

So the wash-up, literally, is this:

As WW noticed and as I wondered about earlier, the glue was too thick.

Upside is that one half needed the min. of cleaning and had a bow tied on it and left for the birthday gal to discover (while I b*ggered off back to the country).

Other side, the one loaded with the 'sauce', took a Scotchbrite and more effort than time allowed to clean up properly.

Just as a BTW, WW, I seem to recall you can hit the dried sauce with meths. Just makes it brittle? No advantage?

Well done you!

Meths will seep into really old dried-out glue and literally divide the crazed and cracked glue, making it easier to break apart, but the moisture content and cohesion of relatively recently applied glue won't allow the meths to work.

[rsser]

Ah. Thanks.

oldiephred, this cylinder was 60cm long, 50mm diam., and the key 'customer' req't was that the top of each half be quite flat.

Would this be achievable with your method?

I'm wondering about the middle flexing outwards.

[Skew ChiDAMN!!]

:2tsup:

That should get you a nice reserve of brownie points. :;

Using Oldie's method you could've turned the central inch down to near final size (bar sanding) at low rpm and fitted a hose clamp. Then turned down the rest at normal speeds.

I've found duct tape, wire twists, etc. don't bind tightly enough - not without marring the wood, anyway - for this sort of work. Then again, I tend to turn at brown pants speeds...

[rsser]

K. But to speculate: the clamp has to come off for sanding, and any bowing apart of the halves while spinning will lead to a dished top once stopped and there go the brownie points .... ?

Anyway, it's been a fascinating and instructive exercise.

Nick, if the missus doesn't want the other half, you're welcome to it.

[Skew ChiDAMN!!]

That's when I resort to the ancient Chinese art of Han-San-Ding. :U

[Sawdust Maker]

...

Nick, if the missus doesn't want the other half, you're welcome to it.

Thanks

But, I was going to suggest that you cut it into a 1/3 and a 2/3 length so she has three different sizes - I'm sure they would come in handy

[Kwors]

So, update.

Lost the lottery.

The good length of redgum that Calm had kindly given me, salvaged fence railings from a stud farm IIRC, had the cranky grain you'd kill for with a pepper grinder or the like, and kill with for my purposes.

Sized it to 6cm square, ripped it down the middle, and then set to with a plane to flatten the glue faces.

Damned if I've seen such a poor result before.

62* cutting angle, close mouth, freshly sharpened A2 blade ... and the tear out was chronic.

Seems it's off to the wood merchant with tail tween legs.

Anyway, Nick to come back to your question, it's called a seam roll, and what it does is allow the seamstress to iron a seam without the seam allowance showing on the outside. Esp. handy with a sleeve eg. when otherwise you'd be ironing 4 layers of fabric.

And I thought I was fussy about finishing.

Hi Risser.
I have some VERY spalted (OK rotted) silver birch that is like turning cardboard, sounds like it behaves like your redgum. I have to do the final shaping with a 4 inch grinder and a sanding disk. But it is very beautiful when finished.