Trouble turning a 4x4

[kalynzoo]

This project is a little bigger than my experience with pens or peppermills. Just finished building a pirate ship playhouse in the grandkids backyard. Still needs paint, but a friend artist has been drafted for special effects.
I am starting to turn a cannon from a redwood 4x4x30. Using a SS faceplate and a live center with the SS510 at slowest speed (no reducer) I am getting too much whobble for any safe control.
I'm prettty sure my ends are square, cut them on the bandsaw using a fence.
I planed down the edges, hope that didn't throw off the balance too much. The 4x4 came from cuttoff stock from the frame, so I have a few more pieces to practice on.
Anyway, any suggestions will be much appreciated. Pictures of the painted completed project will follow.
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[pennview]

I'd try using a drive center in the headstock instead of the face plate. It should turn smoothly then. Draw lines across the diagonal corners of the stock and then use a hand saw (back saw) to cut slots along those lines for the spurs on the drive center.

[greitz]

You can also use the bandsaw to first cut off the corners and make an octagon, to balance the blank better.

"Cut stock that's larger than 3" x 3" into an octagon. This removes excess stock and makes turning safer and easier."

(from the online PTWFE, in the lathe safety section).

Gary

[terrydowning]

I agree with pennview and greitz. It seems like the face plate may be installed off center.

Mounting the face plate so it is centered can be challenging.

I also recommend drilling a 1/8 hole in the exact centers of both ends for the drive spur and live center to seat into. Not too far, just enough to give them something to grab on to.

Use sharp lathe chisels and take light cuts, that soft redwood with its open grain is very prone to tear outs and catches. Softer woods are actually more difficult to turn than hard woods IMHO.

Fear not a dancing lathe, it will settle down when the turning gets round and centered.

[charlese]

I agree with both of the above. Since you are getting wobble, one wnd or and the other are off center when mounted.

I use the corner to corner lines on both ends and drill 1/8" holes, 1/4" deep in the center of the ends. This is where the lines cross.

Instead of using a hand saw to cut grooves for the drive center, I use the bandsaw. Just lazy I guess. The grooves should be at 90 degrees from each other to fit the drive center. If your 4x4 is square, simply cut into the lines you drew earlier.

Yep! face plates are real hard to get centered. The only way I have come up with is to mount a block of wood to the face plate. That block has to be long enough so the extended quill can reach the tail center. By guiding the block into the tail center you can mark (dent) the center of the block. (the block doesn't have to be perfectly square, but should be close) Glue a piece of bond paper to the block. Using a compass, find the center (dent) that was marked earlier and draw concentric circles from that center onto the paper. Now you can glue the end of the workpiece to the paper using the circles as a guide to center the piece.

Yes, it is complicated and troublesome to get the good joint contact between the workpiece and paper. The best way is to first put the workpiece drilled hole on the tail end into the pin on the tail center, then use the quill to put pressure on the glue while you hand center it to the circles. Even then it is never exactly centered, but pretty close so as to avoid wobble.

[paulmcohen]

According to my PowerPro Speed Chart the recommended speed to round a 4"x4" softwood is 430 RPM, if you knock the corners off evenly you should be fine at 700.

If anyone has not played with the speed chart you will be amazed out how much information that packed into it.

[kalynzoo]

Thank you all. Will give it a try this weekend.