Question???

[John Terefenko]

This question is for anyone and especially for John L.



In my topic of lathed turned clocks John Lucas shows a segmented clock face. I enclosed his photo. Hope you don't mind John. I want to make a few clocks like this. Now I can get to the point where I can cut the pieces and glue them up. My question is what kind of chuck and how do I chuck it to turn it??? The problem I see is getting the center of the segmentation in the center of a chuck. What type of chuck do you all use and what is a good method of holding this piece??? If you have some photos that would really be great. Helps in the explanation. Thanks.

 

[MichaelMouse]

I like this solution, because the Forstner that makes the hole has a nice, distinct point to define center. Smaller stuff, or stuff you will support with the tailstock can be held on the pin jaws, others may require a larger bit to make the hole that holds things in place until the other side is ready to mount by the method of your choice.

http://i35.photobucket.com/albums/d160/GoodOnesGone/1-Ash-Plate.jpg

http://i35.photobucket.com/albums/d160/GoodOnesGone/2-Ash-Plate.jpg

Get the hole as perpendicular as possible with your glueups by shimming on the DP table. If you tilt too much, things look silly wide on one side, narrower on the other.

Almost forgot. If your initial glued surface is smooth enough, you can make a PERFECTLY SQUARE waste block with your tablesaw and fence which you can glue on by matching the four corners with radial glue lines. Size it so it can be grabbed by a big set of jaws like this http://www.teknatool.com/products/Chuck_Accessories/PowerGrip.htm as the checkmark shows.

 

[john lucas]

John This ring in the photo is actually only the middle of the larger clock. To get the ring centered I glued it to a 3" square waste block that has an X in the middle. I simply put down some medium CA glue with some accelerator on the segmented piece and eyeball through the hole to get it centered. I then chuck this piece in my 4" jaws and turn it round and flatten this side.
I use a custom made tool that has a 5 degree bevel on both sides and is flat on the front. I cut the side of the ring with the right side of the tool. Then when I turn a hole for it in the clock face I use the left side of the tool to sneak up on the correct size. The Walnut plug has the 5 degree taper and sits in the tapered hole I'm turning. As you sneak up on the size it will start dropping on the hole. Just keep removing a tiny bit at a time until it seats as deep as you want. Your basically setting a tapered plug into a tapered hole. Very easy to get it dead on. When I tried this by cutting square sides you had to take measurements in the Thousands of an inch and if you missed you had to start over or fill the gap with epoxy.

To center the clocks I need a 3" hole in the back for the clock face. If I had a 3" forestner bit I could just drill down a little ways. I don't have one so I take a larger flat wooden faceplate that has lots or rings drawn on it. I put double stick tape on the clock and center it between one of the rings. I will sometimes use my Jumbo jaws but the clock doesn't always sit flat on there.
I turn the back and the inside of the back. Then I turn a 3" to 3 1/2" opening that has a very slight dovetail shape. I can expand my 3" jaws into this to turn the outside of the clock. It's at this point that I insert the walnut ring.
Here is the angle tool I use along with the grinding gauge I use to judge the angles. When touching up the tool I hit the grinder lightly and check it against the gauge to make sure I didn't change the angle. Then I flip the gauge over and check the other side.
Then I true up the back

 

[Joe Greiner]

If the final hole isn't an exact size available in Forstner bits, I'd turn the outside first, by any of the methods already presented. Then mount it in a Longworth chuck to cut the final hole and any surface features. If the chuck buttons are large enough, you can flip the piece to work on both faces. Cole jaws, or Vicmarc's Adjusta-Jaws, would be an alternate to the Longworth.

 

[john lucas]

Joe I've used both the longworth and Jumbo jaws and they just don't hold as securely and may not line up dead on. I find them extremely useful for things that don't need real accuracy like cleaning up the bottom of a bowl or platter.
I flatten segmented rings on them and it's always difficult to get the ring to sit really flat. I guess I need to change the buttons to some other shape.
If I want dead on accuracy I try to use the chucks.

 

[John Terefenko]

John

Getting back to the clock face you have in the original picture with the 12 segments, when you put these together they had square edges because I assume you cut them on a miter saw or a table saw. You then glued them up. How did you center this face???? Some thing like this needs much more accuracy than the simple round disc you show in your second set of photos.

I am going to make an asumption here going by your explanation. After you got the segments glued and dried you took a brad point bit and where all the pieces meet you used this as the center point to drill what looks like a 1/4" hole. You then used this hole to line up on the walnut block with the X on it. Do I have this part right??? Then you went and rounded the face insert with the 12 segments like stated. I don't get where the walnut piece comes in. If you had a photo of the finished clock it might make more sense. Thanks.



Here is what I want to do and you tell me how to chuck this and turn this. Any suggestions is appreciated. I am going to be using an insert( have not gotten them yet so I do not know the exact hole I need) I want to make the 12 segments witha darker wood banding. The insert is 6" round so the segmented piece I will probably make something like 10 to 12 inches with about a 3/4" walnut banding. Do some decorative cuts and the dimensions are not exact yet. When I get the inserts I will adjust. So I need to center my clock insert in the segmented piece but I need to turn it round first and then be able to drill or turn a hole for the insert which I am guessing is about 4" again won't know till I get them. Hope some of this makes sense. I have an idea kicking in my head but am always looking for suggestions.

 

[john lucas]

John If you look at the second photo you will see the white disc is on a 3" square walnut scrap block. This is what I use to turn the discs. I make the 12 sided walnut ring. It has a 12 sided hole in the middle about 1/4" in diameter. I have a 3/8" hole in the exact center of the Walnut block. I put a dowel with a sharpened point through this hole.
Then I simply put some medium CA glue on the walnut waste block and spray some excellorator on the segmented walnut ring. Place it over the tapered dowel and push down. It's not perfect but really close.
I can now put that in my lathe and turn it round. I use my 5 degree tool on the outside to produce a taper. I turn an opening to fit this plug in the main clock part using the 5 degree tool. Then glue it in place. Now I can drill it with a 5/16" bit while it's on the lathe. The walnut insert and the hole should all be centered.

 

[John Terefenko]

That explains it a little better John Thanks. That is something like what I have in mind to try.