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Kuffy
22nd January 2017, 03:13 PM
I had a bowl break off the tenon/spigot while I was nearly complete with the rough hollowing the inside. A bigger set of jaws wouldn't go astray. The bowl is about 9" diameter and about 3 1/2" high. I bumped it a bit too hard with my scraper and off it popped. Oops. The bottom thickness atm is around 10mm, I was pretty much finished.

I reckon I can just mount the bowl in my cole jaws, flatten the bottom and then glue on a sacrificial block and turn another spigot onto that block and try again. but that seems like too much work so....

does anyone have an easier option which results in a decent finished bowl at the end? There is still plenty of meat left around the sides, but the bottom thickness is about where I want it.

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smiife
22nd January 2017, 06:36 PM
:? Is the inside finished ?

pommyphil
22nd January 2017, 06:45 PM
Cut a recess to the outside of your jaws, maybe 4-5mm deep.

And keep your eye out for 100mm dovetail jaws.

KBs PensNmore
22nd January 2017, 07:17 PM
[QUOTE=Kuffy;2002683]. I reckon I can just mount the bowl in my cole jaws, flatten the bottom and then glue on a sacrificial block and turn another spigot onto that block and try again. but that seems like too much work so....QUOTE]

That would be the way that I'd do it, try using hot melt glue on the sacrificial block, when you've finished put it in the microwave or use a heat gun to warm it and the block should practically fall off. Have used this several times for the same reason. The excess glue can be scraped off with a chisel.
Kryn

Kuffy
22nd January 2017, 07:34 PM
The inside isn't finished. If it was I would just level the base with a handplane and call it a day. It looks like a dogs breakfast inside, hasn't even had any work done by the 60grit gouge yet.

I thought about a shallow recess, but I am hesitant to put the bottom of the inside of the bowl so close to the recess. I tend to end up with lamp shades when I do this.

I might give hot glue a go, saves waiting for a bajillion hours for pva to satifactorily cure.

Skew ChiDAMN!!
23rd January 2017, 06:42 PM
Another option would be to permanently glue on a block - grain aligned with what's already there for future stability - and once the inside is cleaned up turn away the bulk of the block to leave a ring which can then be carved into feet?

woodPixel
23rd January 2017, 07:35 PM
After spending hours on a bowl, why would glueing another spigot on be so much tedium? :)

It seems to me that it will be quick thing to do, especially if you have cole jaws.

Show us how you go, I'm forever exploding bowls and snapping attachment points.

Kuffy
23rd January 2017, 08:32 PM
It's tedious because because I have already spent hours messing about square dressing 10" shorts and weird sticks to glue up the silly thing! and now I have to spend even more time "because my tools or machinery did the wrong thing...again!". I often wonder how much time I would save if I used somebody else tools which don't do the wrong thing :D

Nubsnstubs
24th January 2017, 01:51 AM
It's tedious because because I have already spent hours messing about square dressing 10" shorts and weird sticks to glue up the silly thing! and now I have to spend even more time "because my tools or machinery did the wrong thing...again!". I often wonder how much time I would save if I used somebody else tools which don't do the wrong thing :D

That's priceless, Kuffy. Blame the tools. mmm, mmm, mmm....... When I got my first chuck, a Nova G3, I used a tenon that was about 1 13/16 because everything I read stated that the best tenon to use should be one that closes down to the roundest point on the jaws. I see you are doing about the same thing.

After losing about 4-5 pieces that snapped at the tenon, I went with a tenon sized up to 2 1/4". Now, it's about 500 pieces later and haven't lost any at the tenon except a couple burls. Just glued them back on and finished the pieces.

Another thing that will cause separation like that is straight grain. Your bowl look like they use straight across the entire bottom. If you can realign it, put the tenon back on. The glue joint should be stronger than the wood at that point. Glue and joint pressure should be achieved by stacking some heavy items on the bowl after gluing and letting it set for the recommended cure time.

That's going to be a nice looking bowl when done. Don't give up on it........... Jerry (in Tucson)

Kuffy
24th January 2017, 03:45 PM
Yes, I am using a tenon to match my chuck jaws. I was planning on using a bigger tenon when I eventually turn a new one on this piece. The chuck jaws will bruise the hell out of a bigger tenon, but it matters not, because I will remove it for the finished bowl.

smiife
24th January 2017, 07:32 PM
Hi kuffy , I had a similar problem awhile back , and the concensus
was my tenon was too small , maybe get some bigger jaws for your
chuck , you know you want to buy more tools anyway...........:U

Mobyturns
25th January 2017, 11:05 AM
Hi kuffy , I had a similar problem awhile back , and the concensus
was my tenon was too small , maybe get some bigger jaws for your
chuck , you know you want to buy more tools anyway...........:U

Larger diameter jaws would definitely help solve the issue. Looks like the woods that make up the tenon are straight grained and easily sheared, not interlocking grain. The shear strength of woods is an important consideration in determining the tenon size.

You could get away with a 50mm tenon on a large bowl with interlocking grain but not with straight grained timber. So good shingle making timbers are not suited to small tenons.

Christos
26th January 2017, 03:49 PM
.....I reckon I can just mount the bowl in my cole jaws, flatten the bottom and then glue on a sacrificial block and turn another spigot onto that block and try again. but that seems like too much work.......

I can relate that this might seem to be a lot of work and depending on what you have already done with the preparation it might well be a lot of work. As to what you have already said in the steps in repairing this bowl, is exactly what I would do. I would also state that I would use regular glue and wait overnight before looking at this again. Other then waiting for the glue to dry/set I prefer to come at it with a fresh perspective. The fact that it failed is discouraging and when that happens it may lead to other issues, so taking a break(pun) between breaks is not a bad thing.

Jonzjob
27th January 2017, 06:52 AM
If there's enough thickness left in the walls you could always reglue the tenon, or a larger on, back on. It won't be dead centre, but you will finish up with a rather quirky off centre bit of turning?

Make a spigot that fits the chuck but with a larger base to glue on the bowl base. I would follow what others have said and use hot glue, but leave it for an hour before attacking it again.

Try someone elses tools, tey may be sharper than yours? :oo::oo::oo::;

Kuffy
27th January 2017, 03:49 PM
John, I thought of sticking a new spigot on "roughly center" because the wall thickness is still enough to allow for slight discrepancies. But I actually put some effort into making sure the bowl will have symmetry side to side.

I can almost guarantee that other peoples turning tools are sharper than mine. If the machine is doing all of the hard work, why should I bother to keep tools sharp. By the time I am willing to shut the lathe down to sharpen the tool, I can clearly see a facet where the edge is supposed to be, and it is an easily measurable facet!!! However, the scraper which knocked the bowl off the lathe was brand new super duper kinda sharp off an 80g AlOx wheel. My bench chisels and plane irons are super duper sharp when I am using them, but I am the poor donkey that needs to supply the power for em to work, so it's actually a laziness thing as to why I keep bench tools super sharp. Lazy FTW!

smiife
27th January 2017, 07:22 PM
Hi kuffy , I think you have answered your own problem !
Sharp tools should be your number one priority , if you are
pushing hard and nothing is happening, then the tool ain, t
cutting, it, s a bit different with one of your super sharp planes
cos you are the force behind the cut , on a lathe the , it, s the
lathe thats the force , you are just the guide and the tool must
be sharp .......
If you are cutting you will get shavings , like with your planes
If your tool is blunt you will get dust and chips....that tells you
GO SHARPEN YOUR TOOL ,,!,,!

Kuffy
27th January 2017, 08:31 PM
I sharpened my bowl gouge three times to cut the outside of the bowl and up to the point I am at on the inside. I find I can burn the edge off in an instant when working with Jarrah or Blackwood. Two timbers which I have always found to cut hot whether it be on a spindle moulder, router, and even CNC router. It always burns off the same point on my gouge, just as the edge starts to turn up into the wing of the gouge. It ends up covered in black carbon soot except for the 'radiused' edge which melted away. I was actually turning this bowl without gloves, and I kept moving my thumb back because the steel was getting unbearably hot.

I was watching the video footage of when the bowl broke off the tenon and I think I can see what I was doing wrong. Using a bowl finishing scraper, I presented the side of the scraper to the side bowl walls. I did have the handle elevated but that doesn't seem to help because the edge is still presented to the workpiece at 90° or thereabouts. What I should be doing, I think, is moving the handle of the scraper away from me and over the bed of the lathe so that when I elevate the handle I actually have the scraper edge presented at a negative angle and less likely to catch and tear the bowl off the chuck. Either that or I need to get a pair of Incredible Hulk arms.

With a bit of luck, or motivation, I will get some flat panel work sanded and ready for finish tomorrow morning and then I can fix this bowl, or at least start to fix it.

Jonzjob
27th January 2017, 10:19 PM
That's the answer to yer problem!! Yer scraper is toooo sharp :o So wot you got to do is to knock it about a bit and work how yer used to workin init?

I just found your post Smiifie and st as a matter of interest? What is a bowl scraper? All I ever use for my bowls is a 1" round scraper and that gets used for all sorts. Anything that it's too big for and I have a 3/8" round scraper. When I use them in a bowl I always make sure the tool rest is at about the centre of the bowl, or even slightly higher, so that I can get to the centre of the bowl with the handle raised. Then the scraper is presented so that it's giving a definate negative rake. Then if there is any kind of catch it's thrown away from the surface and all I get is a slight kick n the handle. There are exceptions of course and I had one on the little 6" cherry bowl below.

A slightly different situation as it was a VERY wormy bit where several branches parted. Very dry and hard and a knot. The spindle gouge hit the know as I put too much pressure on it and took a lump ut of the side. The bit missing in the photo is only a part of the hole as I had tried mixing a load of shavings with epoxy resin and sticking it back in, but the wood let go and left the shaving/resin mix in place. It stayed and became part of the bowl. The dark areas are cyano soaked bark.

http://i47.photobucket.com/albums/f180/Jonzjob/IMG_0271_zps849thxei.jpg (http://s47.photobucket.com/user/Jonzjob/media/IMG_0271_zps849thxei.jpg.html)

http://i47.photobucket.com/albums/f180/Jonzjob/IMG_0272_zpsym2s2xuu.jpg (http://s47.photobucket.com/user/Jonzjob/media/IMG_0272_zpsym2s2xuu.jpg.html)

I very rarely use glued on tenons and muck prefer a dovetail recess and on the odd occassion I will turn a recess with a tenon in the recess. Sounds a bit odd, but it works plus it looks good to my eyes too. As for the recess, I have always found that a 2 1/2" dia recess is perfectly OK fo 10 or 12"" bowls. My Jacobs jaws in my Axminster Tools K10 Clubman chuck are almost bullet proof and makes the recess an easy option.

I usually start the blank by mounting it with a screw chuck or hot glue on the top surface to turn the out and underside and for bigger bowls a faceplate with 4 screws.

Sorry, I got a bit carried away and off the topic, so I'll shut up ,for now :B

Kuffy
27th January 2017, 10:29 PM
what is a bowl scraper?
one of these. https://www.timbecon.com.au/woodturning/turning-tools/bowl-finishing-scraper

too sharp you reckon? I dunno if you are joking or not but I do find that a freshly ground scraper loves to bite in and catch easily. Kind of like a brand spankin' new 2 tpi bandsaw blade resawing 8" high. The rake of of the bandsaw teeth pull the timber straight into the blade and break the blade or wipe out the power of the motor.

Kuffy
28th January 2017, 06:23 PM
Well I was going to get this bowl repair underway today but there was a big fat doofus continually getting in my way saying stupid things like "yo kuffy, what about the edge profiling?" "yo kuffy, what about those two 120mm holes which require hockey pucks made to fit?" "yo kuffy, what are you going to do about your clients terribad reclaimed Jarrah which is more defect than select!?"

I made the four hockey pucks on the lathe. rough cut the circle on the bandsaw, drilled a 8mm hole in the center and mount it on the lathe using a piece of 6mm to shorten the length of the wormscrew so it doesn't poke out the face side of the pucks. Then I just scraped it down using my bowl scraper because I couldn't think of a better way of doing it except for something like using a parting tool from the face guided along the edge in a straight line. but that just seemed ambitious so I wimped out and scrape turned it.

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Jonzjob
29th January 2017, 10:35 PM
If I may stick my oar in again. When I turn anything like your pucks I start with a square block of wood, slightly larger than the dia of the items and longer than the combined thickness of the pucks. That's to allow the parting off. Stick it between centers and turn to a cylinder the dia you want. Part off to the depth and sand the faces. They are all the same diameter and hopefully the same depth.

Another way is to turn as above, cut to depth on yer band saw and sand the faces..

Good 'ere init

P.S. I'glad that I copied this load of tryping because the system told me that my 'session' had expired when I tried to 'go advanced'! So I will try again, third time, without me smilies?? I hope!

5th try!

Gabriel
29th January 2017, 10:43 PM
Busy busy busy..... I'm sure you'll get the the bowl repair eventually..... Hopefully you're enjoying all the other little odd jobs as well.

Kuffy
29th January 2017, 10:55 PM
Between centers and parting the pucks off would end up having an end grain show side. I needed face grain to sorta kinda match the rest of the piece. Ideally it would have a perfect grain match but I wasn't gonna mess with veneering the parts using a matched set of veneers for the price this dood is paying.

I did get the bowl finished today. It is smooth and shiny and looks like a bowl so it passed my quality control easily. I'll get some photos up tomorrow arvo after werk.

Do you know what happens when you remake a spigot much larger than the first when using the specifications from the chuck supplier to size the spigot?
answer: you turn the big spigot, change cole jaws back to normal dovetail jaws only to find that they are too small so you go back to cole jaws to make the spigot smaller and then back to dovetail jaws. It may sound easy but time consuming, but it is much harder to do when you are giving yourself solid uppercuts at the same time :D

Jonzjob
30th January 2017, 12:04 AM
"Between centers and parting the pucks off would end up having an end grain show side. I needed face grain to sorta kinda match the rest of the piece."

Make your blank with the grain running across the length instead of along it? :wink: :wink:

You say 'the rest of the piece'? What is it? I can't imagine anyone being too interested in matching grain on ordinary hockey pucks? :no:

Kuffy
30th January 2017, 03:28 PM
You say 'the rest of the piece'? What is it? I can't imagine anyone being too interested in matching grain on ordinary hockey pucks? :no:

The 'hockey pucks" as I call them have nothing to do with hockey. They are just 120mm diameter x 30mm thick discs which fit into the hole in the record player plinth. If you look at the photo above, you will see four "hockey pucks" sitting on top of a Jarrah thing. Those hockey pucks fit inside the 120mm hole in the Jarrah thing.

Jonzjob
30th January 2017, 07:09 PM
I don't want to ask the next question :? but I did a search on 'Jarra thing'

https://www.sunfrog.com/Names/Its-a-JARRAH-thing-you-wouldnt-understand.html?70225

That is obviously not what your Jarra thing is, is it? :oo: Woud you be so kind as to enlighten me pretty please :C

Kuffy
30th January 2017, 07:53 PM
405101

Can u see the image? Four "hockey pucks" sitting on top of the Jarrah thing. The Jarrah thing is a solid timber record player plinth made to suit a Garrard 301 turntable.

After my computer finishes rendering a video, I'll post pics of the most awesomest bowl made from s/crap. Takes ages to render video with a $200 PC.

Jonzjob
30th January 2017, 09:46 PM
Is it worth all that trouble for a cheap old turntable like that :o Only kidding , and jealous :C I always wanted one but could never afford it!

I finished up with an Awai LX110 linear tracking programmable jobbie. Works very well but not been used for an age now. Come to think of it none of my sterio has been used for an age now? This retirement is keeping me far to busy busy! Just finished getting ready for a SPANC inspection on Wednesday!!

I look forward to seeing the pikkies.

Kuffy
30th January 2017, 09:58 PM
Ok the bowl is all done. The video is edited and I'll upload that to YouTube this evening and probably schedule the video to be public sometime during the day tomorrow. It took me so long to turn this bowl. I have 5 hours of video footage which included some of the buzzing/thicknessing/ripping of the s/crap boards, but it doesn't include everything I did so the bowl probably spent 8 hours of my time all up.

Anyways, I started with a bunch of s/crap stick offcuts and short not very useful boards which I was beginning to trip over. So I had my way with them and made them into panels. I made sure the panels were symmetrical.
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Then I chose five of the panels to glue up into a bowl blank.
405235

The rest of the leftover panels I quickly made into circles, slapped a champher edge on the under side, sanded the hell outta em and stuck em in a bucket of liquid paraffin. Good for making a sandwich on, or serving cheese or something along those lines. They are only small. I think the biggest was about 280mm diameter.
405236

Then I spent a bajillion hours turning the bowl blank into something which resembles a bowl. It was a pain in the butt to turn this. None of the timbers are hard, but the Blackwood is bloody soft compared to the Myrtle and Jarrah and so 'if' I managed to rub the bevel of my gouge it was kind of jumpy between the harder myrtle/jarrah and blackwood. Probably mostly a skill error on my part, but by the end of it I was wishing I had used River Redgum instead of the blackwood. Live n learn.

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The final dimensions were 234mm diameter x 76mm high.

:think2:

Gabriel
30th January 2017, 10:17 PM
Nice to see the final product.... By the sounds of it you have learnt a bunch again, and im glad you finished it off. Can't wait to view the video....
Cheers
Gab

Jonzjob
30th January 2017, 10:55 PM
Well Kuffy, you have my seal of approval, for what it's worth :U That looks a goodie mate!

I've just had a gander at your lazy sue video. I like the finish on them. The large one I made started out as an English oak TV cabinet that a mate didn't want any more. I've had a boat load of bits out of it now and the lay sue top is the biggest at 18". It's made completly of wood, even to me turning 36, well 40, 5/8" ash wood balls for the race. That was good fun! The original top was done in pine, but I put it to close to the front of our fire and one evening there was an almighty BANG and the top split, so the oak one was turned.

This shows me balls, if you will excuse the expression :-

http://i47.photobucket.com/albums/f180/Jonzjob/Lazys5.jpg (http://s47.photobucket.com/user/Jonzjob/media/Lazys5.jpg.html)

And the spinny bit

http://i47.photobucket.com/albums/f180/Jonzjob/Lazys2.jpg (http://s47.photobucket.com/user/Jonzjob/media/Lazys2.jpg.html)

I won't go off topic any more, but if you wish I'll put another thread on about it?

Christos
5th February 2017, 05:26 AM
Thank you for posting the repaired bowl