Hollowing question?

[gasmansteve]

Hi all
After seeing Mick Hanbury`s excellent hollow forms dvd I am having a go with a nice piece of sycamore about 12" high 8" diameter. Externally I`m happy with it but the hollowing out is proving not so straight forward. I first drilled a hole about 5" deep with the 25mm Forstner I have and then tried to use my recently acquired `Beaver` hollowing tool the one with a ring but because the sycamore is still wet the tool clogs up the second I touch the interior and I`m thinking would it be best to open up the blade on the Beaver quite a bit so it doesn`t clog up so easily or is it perhaps not the right tool for wet timber?
Regards
Steve

 

[cornucopia]

i'm not familiar with the beaver tool but when my hamlet clogs its normally down to two things tip set up and tool presentation- although you can get arward timbers that clog tips easier than others but wet sycamore should cut without any problems.
are you cutting inside 2 out or outside 2 in?

 

[gasmansteve]

Hi George
This is the tool the swan necked version www.toolpost.co.uk/pages/Turning_Tools/ ... ecial.html
I am placing the tool on an angle downwards and drawing it out I think you mean inside to out (??). Maybe I should open the ring up a little to allow bigger shavings? The opening I have at present is about 1.5mm.
Cheers
Steve

 

[cornucopia]

out to in or in to out shouldint make much diffrence but me and paul was messing about the other day and found that pauls munroe was blocking if we went in to out- but as soon as we had a tiny central hole it stopped it, it didnt matter with the hamlet.
as far as i know all coverd ring tools should be presented horizontally on centre- with a 25mm hole down the centre i would normally plunge down the side of the hole enlarging the cavity, then i would start reduceing the wall thickness from top to bottom- 1.5 mm should be plenty- try opening it- try rolling it over to about 11 o clock pick up the shaving then open it to see if that helps.
how slow is it making the hollowing?
what lathe are you using?
is the tool razor sharp?

 

[TEP]

Hi Steve.

You say you have the tip set up with a 1.5mm opening. Isn't that a bit big? I use a Hamlet big brother and never have the cut set anything like that. I'm no expert with these type of hollowing tools, I tend to use a home made Oland tool most of the time. But it may be worth while to close the cut right down, start small and open if you think you need it.

Don't forget big shavings clog up worse than small light ones.

Also on these ring type tools when you withdraw them they always have wood in the gap, but when you start to cut again they do clear themselves.

 

[Paul.J]

Hello Steve.
Not familiar with this tool either,but with my little experience of hollowing using the Munro i would start off doing a fine cut to start with until you get used to the tool.Do as George says and try angling the tool until you find the cut and keep it moving.I have found when i tried a bigger cut it seemed to grab more.These type of tools do take some getting used to i think.You should be getting long ribbons flying from the tool when you get it right

 

[gasmansteve]

George -lathe is a 1/3rd horse Draper (newun on order can`t wait) have it running ok and doesn`t seem to strain anything. Now you mention it the ring sharpness might be iffy should maybe have checked that first :? I stopped hollowing as the tool kept getting clogged up. I have one of those diamond files which should do it.

Tam - The shavings seem well tight in the tool and have to be poked out with a pin file, maybe should experiment with a smaller/bigger opening.

Paul - Yes maybe me not used to the tool. Its my first hollow form (can`t really count segmented stuff ) so still learning with it also it came with no instructions so I used it like Mick did in the dvd. Wasn`t even sure if I was using it right at first as the ring is underneath and not on top as you`d think.

Steve

 

[robo hippy]

I can't remember if the one I have is a Beaver or not, but it is the same type of tool. It seemed that no matter how I adjusted it, it would not cut at all, or would clog up instantly. I use the Kelton hollowers for roughing, and a carbide disc for finishing.
robo hippy

 

[cornucopia]

George -lathe is a 1/3rd horse Draper (newun on order can`t wait) have it running ok and doesn`t seem to strain anything. Now you mention it the ring sharpness might be iffy should maybe have checked that first :? I stopped hollowing as the tool kept getting clogged up. I have one of those diamond files which should do it.


Steve

blimey thats a big piece for a little motor to cope with :shock:

i have been using coverd ring tools for nearly 10 years and i tend to forget how much i use to struggle with them- i originally had a exocet and that clogged allot- in genral i found that too small of a gap can be just as bad as too big- 1.5mm to 1mm is what mine is always set at. the tool is clogged when it refuses to cut anymore- as tam says somtimes they look clogged when there not. its worth polishing the inside of the ring, if its a little rough it will clog easier- but it sounds like a blunt tool is your main problem.

 

[Mark Hancock]

Generally shielded hollowing tools clog because the depth of cut ie gap between the shield and cutting edge is set too big. The bigger the gap the thicker the shaving and the less likely it is to clear and break away. The smaller the gap the more fragile the shaving and the easier it is to clear.

Grabbing by the tool is also an indication that the gap is set to big. Angling or rolling the tool to the left will reduce the grabbing by reducing the depth of cut. This is also a way of not having to continually adjust the depth of cut ie relationship between shield and cutting edge when changing from aggressive cuts to finer finishing cuts.

As has already been mentioned the sharpness of the cutting edge can also be an issue as is the speed of the lathe. The optimum speed is that which allows the tool to do it's job ie allows the cutting edge to enter the wood, create the shaving and allows the waste to clear. This varies with each hollowing tool because of their different designs. For example the Munro can work well at higher speeds than the Hamlet. I use the Hamlet at around 500 to 700 rpm and the Munro 700 to 1000 rpm.

 

[gasmansteve]

Hi folks
Turned out to be the ring cutter not sharp enough.



Once I sharpened it and tilted the tool to about 8 oclock position it started cutting fine. Guess you have to get used to these tools.
Think I`ve got the proportions ok. Must try different finishes I seem to want to friction polish everything as soon as its finished
Thanks again
Steve

 

[Paul.J]

Looks good to me Steve
At least you didn't go through like someone i know
What is the finished size,and how did the lathe cope with that size piece. :?: Should be a lot better when the new one arrives

 

[stevebuk]

wow steve that is impressive, i love it. I think as this is your first hollow form cant wait to see what else you come up with, under the guidance of the best guys around, you will come on in leaps and bounds.
Keep the camera fully charged.. :lol:

 

[gasmansteve]

Paul - it ended up about 9" tall x 8" at widest point. Its not as deep inside as I`d like still about 1.5" of wood at the bottom but I think I need an extention for the forstner bit to get deeper to start with. The smaller hole made it quite hard to start cutting from the centre with a swan neck tool. I had quite a juggling act and glad noone could see me part it off from the face plate as the bowl was heavier than I thought and I must have looked a pillock dancing round the shop with it :lol: . I did wonder if the Draper would cope with it but it seems these little 1/3rd horse lathes are stronger than you think if the balance is ok.
Steve- cheers for that, many lessons learnt and more visits to tool shops required now :lol:

Steve

 

[stevebuk]

hi steve
just thought i'd let ypu know, i am going to my first woodturning club tommorow night, and the guest demo chap is Mick Hanbury, so i am going to take my camera. :wink:

 

[PowerTool]

Very nice work,Steve;particularly like the shape and style of the neck and rim,it's plenty of decoration for such a wonderfully figured piece of timber

Andrew

 

[paulm]

Some really useful advice from the pro's and others on this thread and a good result Steve, well done

Cheers, Paul

 

[TEP]

Crackin' bit of work for a first try Steve. =D>

Bit of advice for when you drill the centre hole depth on starting. Buy a cheap fostner bit about 1" - 1 1/4" and get it welded to the end of a piece of 1/2" bar steel. at the other end leave enough end to fit into a wooden handle, then have a side handle welded on. It works great for drilling to any depth you need for hollowing.

Just make sure you get the 1/2" bar long enough for the job, and run the lathe at SLOW speed while boring, and withdraw often to clear the debris.

If you can't handle a fostner bit, you can do the same with a 7/8" - 1" blacksmiths drill bit.

 

[gasmansteve]

Yes thanks for the tip Tam. You think thats preferable to mounting the forstner in a Jacobs chuck in the tailstock? Seems you might have more control using the wheel on the tailstock to control depth rather than controlling how hard you push with the handle?
Steve

 

[TEP]

Mornin' Steve.

You would have more 'control' boring via the tail stock, but unless you have a lathe with a tail stock quill of more than aprox. 4" travel, deep boring can be a pain. Also bore accuracy is not really needed as you are only laying the path for the hollowing tool. The only accurate bit is the depth of hole for the base of the form. Then if you are a little unsure you can fit a depth gauge on the shaft of the boring bar. Don't forget when making hollow pots of up to about 4 inches deep all you need to use is a spindle gouge up the middle to bore a hole, and gauged by your finger tips for depth.

Also as long as you start central when hand boring, you will stay on centre anyway. It is the start that really counts. It is actually quite difficult to go off centre with the lathe revolving. Just make sure you cut a recess for the fostner/drill to start and away you go.