Newbie Question

[Shane Copps]

I turned a little in High School shop class (quite a while ago) and haven't done any since. I am going to try it again but I need some pointers from you knowledgeable folks. I put a log on my Shopsmith to start turning, centered it the best that I knew how and then I turned it on. The log was out of balance and bounced my Shopsmith all over the shop. Before I could hit the stop button, the log went flying.

The log I have I am using is about 10 inches in diameter and has a few knots. I cut down the knots but the log isn't evenly round. What is a good way to find the center so that I can start this project?

Thanks for any and all help
Shane

[Roger Chandler]

I turned a little in High School shop class (quite a while ago) and haven't done any since. I am going to try it again but I need some pointers from you knowledgeable folks. I put a log on my Shopsmith to start turning, centered it the best that I knew how and then I turned it on. The log was out of balance and bounced my Shopsmith all over the shop. Before I could hit the stop button, the log went flying.

The log I have I am using is about 10 inches in diameter and has a few knots. I cut down the knots but the log isn't evenly round. What is a good way to find the center so that I can start this project?

Thanks for any and all help
Shane

Measure the diameter in 3 locations across.......120 degrees, and mark with pencil. Find center between where all those intersections occurred, and do it on both ends. Make sure you take a punch, or awl and make an indention about 1/4" deep at that center point on both ends of the blank. If you have a center finder, you can do the same thing with it.

The spur center and live center need to be seated well........take a block of wood [to protect centers]and tap the center into the wood with hammer to seat.

Your rpm needs to be slow at first.......until you take off some wood with a roughing gouge to get it in balance. Re-tighten your pressure from the tailstock and you can up the speed some. Flying wood blanks can kill you! Some fatalities have occurred because of this! I recommend you get with an experienced turner or your local turning club to get some instruction!!! Wear a faceshield!!!!

[Barry McFadden]

I have a center finder that works like Roger describes by making a few lines and trying to find the center using them. I found this new center finder at Lee Valley that works much better.. http://www.leevalley.com/US/wood/page.aspx?p=72277&cat=1,42936

[David Delo]

Shane,The slowest speed for the Shopsmith is 700 rpm. Too fast for bigger out of round blanks. Hanging some weight from the bottom way tubes can help but you'll still fight it unless you get your piece balanced on the bandsaw or chainsaw first. One thing that would help you is their speed reducer unit. You can slow the rpm's down with it to 100 rpm's. I think it's a sort of must have for guys that use their SS for anything other than spindle work. You can buy them direct from SS or ebay always seems to have a few listed.

[David Delo]

Forgot to post this video link of the speed reducer in action.

http://www.shopsmithacademy.com/SS_Archives/SS107/SS107_Turning_Burls.htm

[Thom Sturgill]

The geometric center may not be the center of gravity, especially when there are knots or burls. Mount between centers by eye LOOSELY and rotate by hand. Observe if it spins quickly to find a heavy point. Lift one end and repeat. Alternate ends and repeating until it pretty much stays where you put it when you rotate it.

Now TIGHTEN the tailstock up and take some material off to round the piece. If you are taking off one side too much then repeat the above process to re-center once you've removed some weight. Take this time to observe grain and form and make sure that you are getting the best the piece has to offer. If you do have to recenter after taking some off, the offset should not be as much as when you started.

I will agree that the shopsmith is probably not a good choice for out of round blanks. I personally do not care for do-it-all tools, whether hardware or software (I'm a retired programmer/sys-admin).

[Kyle Iwamoto]

How long is the log? As mentioned turning anything "big" on a SS is a shorts changing operation.
Try this. I know it's hard on the SS since the headstock lever puts pressure on the log. Hang the log between centers, with just a little pressure on the log. Do not engage the spur. Let the log drop with gravity. Adjust the off balance weight by backing off the headstock and moving the log higher. Repeat until the log "balances" between centers. Note that doing this will result in the log not being "centered". When you get the log fairly balanced start turning. As you rough, you will need to rebalance the log often until you get it centered and balanced. It will take time. Good luck! The speed reducer is an option too, the balancing and roughing still works. Yes, I do have a SS. Don't turn with it anymore though. Too much excitement for me.

[Cary Falk]

I would make a router sled for the shopsmith. Make a lengthwise pass (with the shopsmith off), rotate the log the witdh of the router bit and make another pass lengthwise. Rinse and repete until it is pretty well balanced. I don't much care for flying logs.

[Roger Chandler]

The geometric center may not be the center of gravity, especially when there are knots or burls. Mount between centers by eye LOOSELY and rotate by hand. Observe if it spins quickly to find a heavy point. Lift one end and repeat. Alternate ends and repeating until it pretty much stays where you put it when you rotate it.



I agree with Thom here.........rotating the blank by hand to get the best balance you can is the best way to go......sometimes wood can be denser on one side than the other, so all things considered this approach is a good one to use.

[Geoff Whaling]

Shane,

We all get rusty ;-) after a long time away from the lathe. Tooling and chucks may also have changed a bit since then too :-)

If you are having difficulty mounting this blank, very respectfully I suggest that you take some baby steps for a while with a few clean knot free blanks of say 3 or 4" dia then work up to tackle a bigger blank like this one.

How long is your "log" that is 10" in diameter? Most turners on this forum would be more than a little concerned for your safety in the situation you have described & about the "log went flying" part. Big blanks out of balance & spinning at high speed can be very hazardous and are known to cause significant injury to the unwary and unprepared turner.

Mounting blanks and lathe speed management are fundamental aspects of wood turning and safety at the lathe. The ShopSmith is a unique bit of kit & as I understand they have a lathe speed range of 250 to 10,000 rpm. If you are turning this blank as a bowl then the recommended speed is about 600 to 900 rpm max using Dale Nish's widely accepted lathe speed formula. With the ShopSmith you will need to pay particular attention to speed management - 10,000 rpm is a very high lathe spindle speed for a lathe, well over twice & almost three times as fast as the majority of conventional lathes on the market.

Get yourself a "center finder" it will make locating centers on blanks much easier http://www.rockler.com/stock-center-finder

Doc Green has a good explanation of Dales lathe speed formula at http://www.docgreenwoodturner.com/lathespeed.html and has many other good tips in his articles index.

Check out Jon Siegel's very good articles at http://www.bigtreetools.com/articles.html and see if you can locate a copy of Keith Rowleys “Woodturning – A beginners Guide.”

Stay safe, by starting off small & working up. Gain experience in an environment that is unlikely to cause serious harm, then progress. Hopefully you can find a club or a woodturning mentor near you to get you going with the basics again.

Don't be complacent a 10" blank at high speed can do serious harm, please get some assistance & mentoring.

[David Delo]

Shane,

We all get rusty ;-) after a long time away from the lathe. Tooling and chucks may also have changed a bit since then too :-)

If you are having difficulty mounting this blank, very respectfully I suggest that you take some baby steps for a while with a few clean knot free blanks of say 3 or 4" dia then work up to tackle a bigger blank like this one.

How long is your "log" that is 10" in diameter? Most turners on this forum would be more than a little concerned for your safety in the situation you have described & about the "log went flying" part. Big blanks out of balance & spinning at high speed can be very hazardous and are known to cause significant injury to the unwary and unprepared turner.

Mounting blanks and lathe speed management are fundamental aspects of wood turning and safety at the lathe. The ShopSmith is a unique bit of kit & as I understand they have a lathe speed range of 250 to 10,000 rpm. If you are turning this blank as a bowl then the recommended speed is about 600 to 900 rpm max using Dale Nish's widely accepted lathe speed formula. With the ShopSmith you will need to pay particular attention to speed management - 10,000 rpm is a very high lathe spindle speed for a lathe, well over twice & almost three times as fast as the majority of conventional lathes on the market.

Get yourself a "center finder" it will make locating centers on blanks much easier http://www.rockler.com/stock-center-finder

Doc Green has a good explanation of Dales lathe speed formula at http://www.docgreenwoodturner.com/lathespeed.html and has many other good tips in his articles index.

Check out Jon Siegel's very good articles at http://www.bigtreetools.com/articles.html and see if you can locate a copy of Keith Rowleys “Woodturning – A beginners Guide.”

Stay safe, by starting off small & working up. Gain experience in an environment that is unlikely to cause serious harm, then progress. Hopefully you can find a club or a woodturning mentor near you to get you going with the basics again.

Don't be complacent a 10" blank at high speed can do serious harm, please get some assistance & mentoring.

Geoff,

Good advice but just 1 correction/caveat. The SS speed range is 700 to 5200 rpm's. for standard headstocks 500 thru 520. The reducer on these units allows rpm range of 100 to 743. The newer Power Pro (DVR) headstock does allow for 250 to 10,000 rpm. The OP didn't specify which headstock he has but I'd be surprised if he had the newer version since he said he had it on the lowest setting and it still walked across the floor.

[Geoff Whaling]

Thanks Dave, I checked out the ShopSmith specs on a couple of sites. http://www.shopsmith.com/markvsite/lathe.htm Some stated what you mention and others were not that clear so I went for the worst case. We don't see ShopSmiths in Australia but there are some very old combination machines similar to the ShopSmith still about.

700 rpm is a little to fast to start a rough well centered 10" spindle blank or bowl blank. Scary starting off at a 700 rpm speed with an out of balance blank. 5200 rpm is still a very high spindle speed and can get one into serious trouble.

[Shane Copps]

Thanks guys.

I had the SS set as low as it would go (700)- I do have the older headstock. I was pretty scared to see the log go flying(it took off away from me) and that is why I'm looking for help and advise before I try it again. As an EMT- I don't need to be my own patient. :-)

Thanks for the advise and links guys- I do appreciate it.
Shane

[Geoff Whaling]

Thanks guys.

As an EMT- I don't need to be my own patient. :-)

Thanks for the advise and links guys- I do appreciate it.
Shane

One of the good guys :-) like preaching to the converted about potential injuries.

I sincerely hope you can find a way to reduce spindle speed significantly if you wish to pursue this sort of turning. In the meantime hone your turning skills on smaller spindle & bowl work that is safe to turn on that lathe setup. Unfortunately all machines have limitations and it looks like a ShopSmith is not a good choice in this instance.