>Well, I finally succumbed to all of the beautiful ornaments on this forum and decided to try to hollow a ball--just to see if I had a clue. I don't.
Made a neat little hollowing tool out of an allen wrench, fixed it to a nicely turned handle, and went at it. First drilled a hole in the center of my ball about an inch deep. Then tried to ease the scraper into the hole and hollow the thing out.
Well, after a numbing catch, I picked up the tool, which now has a very useful offset shape to it. Turned off the lathe. Congratulated myself on wearing a face shield (even though it didn't hit me in the face). Bandaged up my finger, which somehow took a little scrape and was bleeding a bit. Went back to making the table for my daughter that I was supposed to be working on anyway.
Before I try again, can anyone direct me to the proper grind for one of these tools, and also how to use without risking injury? If it's been discussed, just tell me and I'll search away. I didn't find on an initial search.
To hollow a Christmas ornament I first glue the block to a wasteblock. Then I turn the outside leaving about a 1� tenon for stability. After I finish the outside I drill a 3/8� hole all the way through the ball portion.
I use 3 tools to hollow ornaments.
About 70 percent of hollowing is done with the 45 degree bent tool. I very seldom use the curved tool. This tool is for cleaning up the inside bottom of odd shaped balls that the other tools won�t reach. On a round ball you can hollow all but the very bottom using nothing but the straight tool.
I start the hollowing by enlarging the bottom hole to about ��. Then I reach in with the straight tool and hollow a little going to the left pretty far. Then I go in deeper and hollow to the left to make a step. I repeat this process so the inside of the ball looks like this with a series of steps. In this photo the bottom of the ornament has already been hollowed with the bent tool. I thought it showed the steps better. After I get the first set of steps I use the bent tool to hollow the bottom. After this I use the bent tool to hollow the next step over to the side. You can feel these steps very easily. I will hollow each step back about a ��. You can do this very easily if you�ll just squeeze your left hand which pulls the tool a very precise amount. After I get the all of the steps �� over I�ll repeat this move. When I get close to the sides I�ll stop and measure.
These are the measuring tools I use. The big C on the left has a gap of 1� The L�s work by touching the upside down L to the place you want to measure. The rightside up L is inserted through the hole. You touch the wood so the top pieces align and the bottom gap will show you the thickness. The one on the right is a small tool made just to measure the thickness of the bottom of the ornament. These are all made from thin brass or copper wire.
To use these tools it is important to have the tool perpendicular to the wall.
Notice that the gap in the big tool is 1� So the photo shows us that the wood is about �� thick at that point. If you don�t keep the tool perpendicular to the side you will get an inaccurate reading. The small tool on the right has a �� gap so the reading shows us that the ornament is about 1/8�
This is the grind I use on all of my hollowing tools. The tools are �� but I grind the tip down to a little thicker than 1/8�. The reason I do this is that the tool doesn�t take as big a bite and doesn�t twist in your hand as bad. When ever you feel the bent tool trying to twist stop and clean out the shavings. If it gets really full it will grab the tool and rip out the side of the ornament.
Try to keep the handle of the tool slightly higher than the tip and the tip should be slightly above center on the ornament. If you get below center it will either stop cutting or it will get a catch.
The big rounded tool is used differently than the others. This tool is only used when you need to reach around a corner. This one is not bent correctly. The tip should line up with the center of the shaft. The tool is used with the tool rest on the straight part of the shaft. This helps reduce the torque on the handle. You could also do the 45 degree tool like this but I find that the torque is usually manageable on that tool.
I obviously don't know how to put photos in the text. If someone will explain this to me I'll try this again. If not send me an e-mail and I'll just send you the document. I'm just not a computer person. I'd rather be on the lathe.
>here are the directions for posting pics (straight from the FAQs):
First, each image you want to include must have a URL. In other words, it must reside on an Internet server so that it may be accessed from other computers on the Internet.
Once you know the URLs of your images, you can insert them into messages by using HTML "image tags" wherever you want to place an image. A sample image tag would look like this:
Note that the URL is enclosed in quotation marks. Don't forget to use both opening AND closing quotation marks. If you like, you can highlight and copy this sample image tag and paste it into your message, replacing the domain and filename placeholders with the actual URL of your image. To make sure you've done everything correctly, be sure to preview your message before posting.
You can make images appear to the left or right of the text that follows them by using the "align" attribute inside the image tag.
For example, to place the picture to the left of following text, your image tag would look like this:
To place the picture to the right of following text, your image tag would look like this:
>Great response! Thanks for that explanation. If anyone is using homemade allen wrench scrapers--I'd appreciate a hint as to the grind you use--I'm presuming it's just kind of rounded with a fairly steep back bevel.
Thanks. It didn't understand 90 percent of what you said but it's interesting. I don't have any idea how to give a photo a URL or post it anywhere else. I'm doing good to get it through photo shop. I finally figured out that computers are like Math to me. It just doesn't stick. John
>Jay, two things about your tool, first, rotate the tool tip down to about 9 o'clock and touch the surface to be cut. Now rotate it gently clockwise until it starts cutting. Never touch the tool to the surface above center.......
Shape the end of the allen wrench by grinding a flat down to near the centerline. Grind the profile like your little fingernail. The relief angle doesn't need to be more that 10 or 15�.
>Hold on, Jay, lets get this straight -- the future of your fingers in involved...
First -- a lot of the mystery and danger of using these tools is that when you work through a small hole, you can't see what's happening, and your movements are restricted. I very strongly recommend practicing with any new hollowing tool, no matter how small, on a small open bowl.
The sort of tool you describe is basically a small round-tip scraper on a curved shank. Standard scraper rules apply: Cutting edge should be a angled downward slightly; keep tool rest on the straight part of the shank; inside the bowl (or ball) keep the cutting tip ABOVE center (catches push the tool into air, not wood); outside the bowl, use scrapers below center. If your cutting tip gets below center on the inside -- WHAM ! -- ceiling ornament.
I think what Jim is getting at is that you don't want to rotate the tip clockwise to bring the cutting tip up to meet the wood above center, it needs to head down about 5 - 10 degrees. If the bevel rubs the wood well above center (with tip rotated CW), you're in trouble. In fact, bevel rubbing is not what scrapers are meant to do... With the lathe off, you can rotate the tool CW until the bevel is against the inside of a bowl, and hand-rotate the piece to see the catch develop -- at 1200 RPM it would be nasty. As long as the tip is rotated CCW, cutting at center is fine; cutting above center is better. If you are going in through a small hole, and you want to cut above center with a downward rake, you may have to have the handle a bit low, and aim the tool above center a little, with the CCW rotation lowering the tip toward center height. This also gives some shear angle to the cuts.
This is all a little difficult to explain, but easy to see if you practice using these tools in a small bowl shape. You could even hollow both halves of a 2-piece ball this way -- just make a lidded box with a tight fit that you then glue together. If you are holding onto the tool handle with a white knuckle grip, something is probably amiss -- practice on a little scrap bowl so you can see what's up.
Basically, the smaller the opening and the more extreme the bend on the tool, the steeper the learning curve on this project.
