woodbowlsandthings

March 6, 2016

Oneway Easy Core Laser aid

I have and love my Oneway Easy Core System. Before I purchased it I watched a video on the Oneway website which really got me going in the right direction and help me decide this was the coring system I wanted.
In the video were instructions to make several spacers that enable the user to position the cutter appropriately for whichever set of knives were being used.
I made dutifully made the spacers

IMG_2228and labeled them although they worked as advertized they never really worked as well has I had hoped, primarily because I often use different chucks and sometimes want to position the cutters off center.

Whenever I would use a different chuck or a different location for the cutter I was mostly guessing what the core would look like and exactly how thick the bottom would be.

At first I would position the system where I thought it should be and by holding the cutter over top of my wood, sort of swing it back and forth and look down from the top to try to guess what I would wind up with.

Next I made a pointed stick with a metal rod attached that I could position over the cutter and adjust it for each size of cutter. This actually gave me a better idea of where the cutter would cut, but still not quite what I was looking for.

I soon realized that I wanted a better ‘mouse trap” and realizing that I could easily adapt the laser from my Kobra Hollower to accurately position the cutter without the concern that I might cut too thin a bottom or even go through and hit my chuck.

Here is a photo of the set-up I am now using, it’s fantastic! Quick to set-up and adjust no matter which size cutter I’m using or how I have the blank mounted.

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I simply measured from the center of the pivot to the outside edge of the cutter and scribed these distances on the arm of my Laser. I have the three smallest cutters. Measured from the center of the pivot to the outside edge of the cutter they measure 5″ – 6 1/8″ – and 7 7/16″.

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I am lucky that I use a 1″ threaded bar to adjust a router table when I use it on my oneway and was able to utilize it on the end of my Kobra Laser.

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While taking these photos I thought why don’t I also do a mock-up that could be utilized  by turners who either don’t have the same laser set-up I do or don’t already have a laser.

Here is a similar design that anyone with the Onway Coring System can easily make and use to take all the guess work out of the process.

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If you decide to make this tool, don’t forget to make the upright long enough for the biggest bowl that you can turn on your lathe.

Here are the components. First the bar to hold the laser and enable it to be adjusted for each cutter. I left mine a little long just in case I ever get a larger lathe. I drilled a hole for my laser a little smaller than it’s diameter, cut a slot with a hole at the end to allow the bar to open and gently pinch the laser. I then drilled holes for a screw to allow for the adjustment for each cutter as described above.

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These are all the components. I suggest that if you are following this design you fill the hole in the end of the upright with superglue to strengthen it(don’t insert the screw until the glue has hardened the wood around the hole). This will allow you to use it many times without stripping the screw hole.

IMG_2225In use, both designs work wonderfully. Here are a few photos of them in action.

One other major advantage of this design is that if a blank has bark or a natural edge it is easy to see exactly where the cutter will cut relative to that.

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February 16, 2016

Pro-forme Hollowing tool

Last week while I was hollowing an 8″ tall cup form I decided it was past time that I tried the Pro-Forme Hollowing tool that I bought about 5 years ago.

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It has been sitting mixed in with the rest of my hollowing tools and every once in a while I would take the plastic cover off of it and then put it back. I had read that it was especially nice in end grain and even better if the wood is green. Today was the day for a trial. I put it in my Kobra Hollower, but before I started to hollow I drilled a hole with one of my modified spade bits to the depth I wanted to go. The Pro-Forme was set at the factory and worked like a charm. With practice I’m certain I could get as good or better finish inside than is possible with a scraper. I did notice that as I got beyond about 6″ the 1/2″ bar I experienced a little vibration but I was able to go the full 8″.
Thinking about how much I liked the way the tool worked and seeing that I had a spare cutter I felt I should do something to help with deeper hollowing. My first thought was to ask a friend of mine if he could make me a 1″ bar with the end modified to fit the Pro-Forme but this of course required me to buy a 1″ polished steel bar and seemed like it might be more work than it was worth.
I realized I already had a 1″ bar for my Kobra and all I needed was a short extension that could be installed in that bar to which I could attach the Proforma.
Luckily I have a few pieces of drill rod hanging around my shop and was able to find a 2 1/2″ long piece of 1/2″.

I clamped it in a vise and proceeded to notch it out with a zip cut blade my cordless grinder.

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After some grinding, polishing and filing I completed the adaptor and hopefully can now go up to about 14″ deep.

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June 16, 2014

Sanding the inside of a Hollow Form

Occasionally I really want a really good finish on the inside of a Hollow Form no matter how big the opening is. An example would be when I want to pierce the form with some sort of art that would allow people to get a good look at the inside. Another might be when I make a Hollow Form influenced by harvey Fein. His work frequently has openings in the shape of slits or slots that go all the way through the piece.
To this end I read somewhere that if pieces of broken tempered glass are put inside and slowly rotated they will eventually finely finish the inside.
I am presently experimenting with this process and have rough turned the inside of a couple of blocks of Birch. I used my Kobra hollowing system and made no attempt to get a smooth interior. I did perform a final light cut with a freshly sharpened cuter. The intention was to leave some roughness and some ridges.

The blocks are about 3″ square and 5 1/2 long.
Here is a photo of the devise I cobbled together with parts I had laying around.

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It enables me to angle the turning if I want more finishing done towards either end. The original BBQ rotisserie motor turned twice as fast as my current one. I had planned to turn a week with it slanting towards the top and a week towards the bottom but during the process I decided I needed to keep track of revolutions rather than days/weeks.
Here is a picture of one of them prior to beginning the process.

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Here is a photo comparing the one on the left (unsanded) and on the right the sanded one.

This was accomplished in about 8600 Revolutions.

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As you can see the section on the left does have a much nicer finish and actually feels as if it has been sanded quite well. It did not however remove much of the ridges. I think I will devise a faster turning model and give it a try again. Sanding with more revolutions this time.

On another thread someone suggested the addition of marbles along with the glass and this I will try next.

January 1, 2014

Small Hollowing Tools

Recently I decided I needed some small hollowing tools because I really like to hollow through small holes.

I started to make my own but Christmas came and I was given a  gift certificate to my favourite Toy Store “Lee Valley Tools”. So I decided it might be best to purchase a small set of tools.

I had done a lot of research on the subject and pretty much knew the size I wanted. I was looking for 3/8″ diameter and would like to hollow through a 1/2″ or 5/8″ hole. I bought the Kelton mini hollowing set which has one straight and two progressivly bent cutters. The store didn’t have any on the shelf but had a set on display complete with wax/plastic cutter protectors and I decided buy them.

I was pretty excited, lots of good reviews so I could hardly wait to give them a try. My excitement abated pretty quickly after I got home and when I pulled off the protectors. The ends were very jagged and would need a good grinding to get them smooth and round. They looked very much like a lot of things I see which are made offshore, although I am unsure if this is the case.

After a little soul searching I decided that I didn’t want to grind them round and then find out that they didn’t work well as I would then no be able to return them. Incidentally, every one with whom I discussed these tools rated them very high BUT to a turner they all said the only way to sharpen them was to lightly stroke the bevel upwards with a diamond hone. As well, I was cautioned not to grind them and to never touch the top of the tool as this is where the very thin hardened cutter was and it could be damaged or removed very easily!

So back to Lee Valley to return.

I already have a 1/2″ set of John Jordan hollowing tools and like them vey much especially when used in my Kobra Hollowing Rig, so I decided to order his 3/8″ set. Still waiting for it to arrive.

Now, as I said I had originally planned to make my own and while I was waiting the 3/8″ cutters that I had ordered from JJ arrived at my shop I decided that I might as well make a couple of tools cause I now had all the parts.

First I used my wood lathe to drill 3/8″ holes in the ends of two pieces of 3/8″ drill rod.

Then using the John Jordan bent tool as an example I proceeded to heat and bend the both bars, one with a slightly less bend than the other. I do find that with the JJ tools I have trouble getting back up near the opening and hoped by creating one tool with a little more bend it might help me.

As you can see from the photo, I installed a small set screw to hold the cutters and if you look close you will see the the tip of the cutter lines up with the centre of the shaft. I would have like the bends a little closer to the end of the bar but because I had already drilled the holes for the cutters I couldn’t bend past the end of my hole.

Bent tools
The problem I was dealing with was how big a hole to drill in the 3/8″ rod to hold the cutters.

As you can imagine the larger the whole the less material is left to support the cutter and to thread for a set screw.

I had been told the easiest way to attach the cutters is with CA glue but I have made a little jig to sharpen the cutters and need them to be removable in order to use my jig.
Looks a little like this but can be modified to change the sharpening angle.
JJ Sharpening jig
JJ tools come with square cutters that have the end that is inserted into the bar turned round to enable it to fit in a 3/16″ hole.

I quickly found a short section of 1/2″ aluminum round stock. Drilled a hole in the end to hold 3/16 square. Drilled and tapped a hole for a screw to hold the cutter in place and found it pretty easy to mount in a drill and run against my grinder to round the end.

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Now all I have to do is try them . . . .

If you have any questions please feel free to post here or email me.

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