Large Platter/Wall Hanging -work in progress

[Thomas Canfield]

A goal when I purchased my Powermatic 3520B in '07 was to turn a large platter at least once. About 4 years back I got some slabs of Ash that I stored vertical in garage with ends sealed to air dry. The largest was 3-1/2"T x 20" W x 60+" long with trimmed sides off bandsaw mill. I had some additional material about 3"T x 20" W with waney edges. I cut the thinner slab and trimmed down to 7-1/2" W. I made a sled arrangement to level both sides of the 20" W piece with router to clear up warp in drying, and then ran it through a friends wide belt sander to get real flat surface for faceplate 4 mountings and edges trued on jointer to get true square faces of now 2-7/8"T slab. The smaller slab sections (20# each) were flattened on friends 8" jointer and edges joined and run through a planer to have uniform 2-1/2" T each side to help balance.

I had taken a day workshop with East Texas Woodturners club in '07 with Frank Penta doing his 3 axis base 9" platter and made some adjustments to use Stronghold #4 jaw chuck for this 33" platter. I made 3 different test pieces out of pine on offset dimension and settled on 1". I am using a 6" Oneway faceplate with 12 - 1/4"x1" lag screws and have a Don Pencil center finder with 5/16" pin. I found the center of the 20" wide section and layed out the center and 3 offset centers. I made a guide drilling a 5/16" hole with drill press in 2"T board to establish true holes. The faceplate was positioned using center and a location screw was set to hold faceplate to mark the 12 holes for 1/4" screws. A total of 56 holes were eventually drilled. Attachment 382996

Biscuits were added in the waste area of the slabs and the section glued up with a flat top side. Hate to admit that the first glueup was hurried and bad joints. Then had to rig up to rip the slab to remove glue joint and do it again. Second time was successful. Attachment 382994

Then to bandsaw. I set up 3 way stands with roller balls to allow rotation of slab which weighed about 75 pounds going to the saw. A friend helped carry the slab and it cut easily rotating by hand. 28 pounds of slab were trimmed off at bandsaw. I wrote the thickness at center on both sides for reference and plan to be able to check wall thickness from those reference points.Attachment 382999Attachment 382998

Mounting the faceplate in the "0" center and mounting on lathe with friends help, with NO TAILSTOCK live center for security, the speed was slowly raised from 0 to 190 rpm (33 x 190=6270) with no vibration. It was a little clunky getting the back leveled off with the 1/4" difference in slab thickness, but not that bad. The back was then worked down out to edges slowly and the edge and front face trued up to get a good balance ready to go to the offset centers. The speed was increased a little up to about 250 rpm as progress was made. It was easy to bog down the motor if the cut size got to big cutting at the larger diameter for sure. The base was flattened and concentric areas for chuck and first reduced area done. I left the tenon 3/8" high to get a good grip doing the face and hollowing. I will plan to leave a tenon on inside to be able to work down the base tenon and then use the base recess to chuck and turn off the inside tenon later. (Working without a tailstock does make one think through the processes and there is no going back.)Attachment 382997

I was able to block up with wedges under the piece for support to remove from lathe by myself and piece now weighs about 45 pounds with 5# of faceplate. Then came shifting to offset centers and turning the overlapping circles at the offset centers. The 33" D piece is now spinning like a out of round 35"D piece but lathe is stable for sure at the 190 rpm. The care in drilling the face plate mounting screw holes paid off and it is easy to change centers precisely.

The base has gone through all 4 centers but needs detail work of texturing done. I am making some cardboard templates to help determine the shape of the platter face putting a bowl shape in the 20" W section and planning on something out in the glued section rim that can be dyed or otherwise help hide the glue joint and grain change.

I have mounted the piece in all 4 centers and so far no real problems encountered.Work in progress and will report more in weeks to come.

[John Keeton]

Tom, the pics do not seem to be viewable. Also, if the platter is used as a wall hanging, the decorative base won’t be visible, will it?

[John K Jordan]

Good fun! I've used Frank's 3-point offset method and like the effect, but with a screw chuck instead of a face plate and an 18+" diameter to just fit over the 3520 bed. I wonder if Frank himself has ever done one that large! Perhaps you could send him a few pictures of the turning and finished piece. Someone might look at your faceplate screw pattern and scratch their head! - great idea.

JKJ

[John K Jordan]

Tom, the pics do not seem to be viewable. Also, if the platter is used as a wall hanging, the decorative base won’t be visible, will it?

I could see the photos if I clicked on the links. Don't know why they didn't display as thumbnails or why you couldn't view them but here they are:

TC_01.jpg TC_02.jpg TC_03.jpg TC_04.jpg TC_05.jpg

(Thomas: we can add these to your original message if you like.)

I wondered about displaying the base too - maybe it could be displayed in way to show both sides.

JKJ

[John Keeton]

Thanks, John. It may be that you can view the pics because of your moderator status. The links take me to an SMC page.

[John RStegall]

Tom, I hope you will bring this to the next club meeting next week. Would love to see it in person.
John

[Thomas Canfield]

I had trouble getting write-up done last night and early this morning had problems getting pictures to open to preview. Just gave up and got it posted. After posting clicking on the file opened the picture so I knew they were out in cyberspace somewhere and the great SMC support would do something. Yes, as a wall hanging the back will not be viewable, but plan to also make an easel to display it on table guessing that it will weigh about 5-7# and top heavy standing. I took a Nick Agar workshop day on Viking Bowl a couple of weeks back and am planning on doing some texture and airbrush. He had a day on platters that I had signed up for but had to change last minute and use info obtained somehow. I was not about to trust a screw chuck on something this big having pulled the screw out of smaller pieces. It still weighs about 45# until I decide and do the back to leave material thick for support texturing and detail. Doubt I will be taking it to a club meeting until move around to face side and get weight down.

[Thomas Canfield]

Good fun! I've used Frank's 3-point offset method and like the effect, but with a screw chuck instead of a face plate and an 18+" diameter to just fit over the 3520 bed. I wonder if Frank himself has ever done one that large! Perhaps you could send him a few pictures of the turning and finished piece. Someone might look at your faceplate screw pattern and scratch their head! - great idea.

JKJ

Here is the faceplate with center pin in one of the three axis 5/16" D holes, a single screw set in the inner ring to hold faceplate stationary, and the use of pattern transfer punch to fit the screw holes of the outer diameter and provide a center punch location to drill the 12 holes for attaching the faceplate with 1/4" screws. One rib of faceplate was marked as index to help orient the faceplate when moving between centers. I strongly recommend this method if a faceplate is to be removed and then reinstalled to get mounting back in original position. I did not mention but all the drilled screw holes were chamfered to prevent the screws extruding wood around the screws and not have full support of faceplate. Faceplate Drilling.JPG

[Jay Mullins]

Thanks John, I couldn't open them either.

Jay

[Thomas Canfield]

Here are a couple of pictures of work to date. The wall hanging side has been air brushed and offset turning in center carved and decorated with last recess to be carved out when inside finished. There are 3 coats of modified Danish oil on inside that need to dry before buffing and fourth applied. I have made a 7"D vacuum chuck to "hold" the platter inside to allow rotating the piece to finish the last carving on recess and apply lacquer finish to the dyed side. The aluminum folding easel/hanger is in welding shop and will need wood sections and leather pad added. The air brushing was practiced on some other wood, but this is the first major try and it shows. Still dramatic for sure. Wall hanging on lathe.JPGPlatter on lathe.JPG