Trying Something New

[crokett™]

I have been watching Lyle Jamieson's videos.  In one of them he talks about turning rough bowl blanks.  I have always attached a face plate to the blank, but the problem is the blank being out of balance.  To combat that I've attempted to round the blank off on a bandsaw first.   This helps but isn't perfect because the blank can be different thickness at different points.  His method is to find the balance point between 2 centers on the lathe and then turn between a spur and live center.  I decided to try that last week.  It took a bit of work to find the balance point.  Also it seemed a bit sketchy to hold a blank without a face plate.  I let the lathe spin for a while before I was satisfied it wasn't going to fly off.   In the end it was safer than an out of balance blank on the lathe on a face plate.  So I think in future I'll be switching to that method.    A compromise could be to find the balance point, then come up with a centering jig that centers the face plate over that point.

[MichaelMouse]

I have been watching Lyle Jamieson's videos.  In one of them he talks about turning rough bowl blanks.  I have always attached a face plate to the blank, but the problem is the blank being out of balance.  To combat that I've attempted to round the blank off on a bandsaw first.   This helps but isn't perfect because the blank can be different thickness at different points.  His method is to find the balance point between 2 centers on the lathe and then turn between a spur and live center.  I decided to try that last week.  It took a bit of work to find the balance point.  Also it seemed a bit sketchy to hold a blank without a face plate.  I let the lathe spin for a while before I was satisfied it wasn't going to fly off.   In the end it was safer than an out of balance blank on the lathe on a face plate.  So I think in future I'll be switching to that method.    A compromise could be to find the balance point, then come up with a centering jig that centers the face plate over that point.

How about using something much more secure than a spur center?  Pin chuck/jaws is my choice.  With the pin chuck you can't knock the piece from between centers even if you're lazy and won't remove some mass at the heavy places with a forstner to compensate for too-rapid rpm.  On occasion, wood screws and washers may be used on the light side.  

Advantage after curing a blank is that a quick rebore allows a centered remount for truing the outside between centers, then cantilever for bottom pre-finish.  Safe and convenient, though low enough rpm is available on my 3K, where it wasn't on Ol' Blue.

[crokett™]

How about using something much more secure than a spur center?  Pin chuck/jaws is my choice.  With the pin chuck you can't knock the piece from between centers even if you're lazy and won't remove some mass at the heavy places with a forstner to compensate for too-rapid rpm.  On occasion, wood screws and washers may be used on the light side.  

Advantage after curing a blank is that a quick rebore allows a centered remount for truing the outside between centers, then cantilever for bottom pre-finish.  Safe and convenient, though low enough rpm is available on my 3K, where it wasn't on Ol' Blue.

What does a pin chuck hold onto with a bowl blank?  One side of the blank is flat from the chainsaw.  The other side is usually the outside of the log.  I didn't work on the entire bowl with a spur center.  I roughed it round and turned a tenon.  I then mounted it in a proper chuck for the rest of the turning.    However, the initial turning finding the balance point is an improvement over a face plate which may not be at the balance point.   That's why I'm thinking of finding the balance point, then designing a centering jig that will center the face place over that point.

[MichaelMouse]

What does a pin chuck hold onto with a bowl blank?  One side of the blank is flat from the chainsaw.  The other side is usually the outside of the log.  I didn't work on the entire bowl with a spur center.  I roughed it round and turned a tenon.  I then mounted it in a proper chuck for the rest of the turning.    However, the initial turning finding the balance point is an improvement over a face plate which may not be at the balance point.   That's why I'm thinking of finding the balance point, then designing a centering jig that will center the face place over that point.

It holds on to the inside of a suitably-sized hole bored in the center of the rim side.  Already balance plays.  These are re-turning pics, but rough starts (and reverses) the same. 

[attachment=39793]

[attachment=39794]

Pin jaws are an alternative for small stuff.

[greenacres2]

I’ve been using a Safety Drive Center since being introduced to it. Mine is the Robust, Oneway makes a good one as well. Secure to start, and any catch basically stops the blank while the safety drive spins, reducing violent reactions. Makes it very easy to find the balance point ala Mr. Jamieson’s method. When my instructor showed it to me the first time I was concerned, but works as advertised. Also makes it easy to reposition if the wood presents a better opportunity to show well while roughing the outside.
Earl

[crokett™]

I’ve been using a Safety Drive Center since being introduced to it.  Mine is the Robust, Oneway makes a good one as well.  Secure to start, and any catch basically stops the blank while the safety drive spins, reducing violent reactions.  Makes it very easy to find the balance point ala Mr. Jamieson’s method.  When my instructor showed it to me the first time I was concerned, but works as advertised.  Also makes it easy to reposition if the wood presents a better opportunity to show well while roughing the outside.
Earl

Are you talking about this?
Safe Drivers (oneway.ca)

You don't have problems with the stock stopping when you are cutting even without a catch?

[greenacres2]

Are you talking about this?
Safe Drivers (oneway.ca)

You don't have problems with the stock stopping when you are cutting even without a catch?

That's it.  Here's the Robust version Live and Drive Centers | Robust Tools (turnrobust.com)  The Bowl Attachment screws on and probably about 1" to 1 1/8" in diameter, and i use that to start most bowls.  Don't see that option on the Oneway, but it may be listed elsewhere.
No problem with stock stopping as long as the tools sharp the the "tool-holder" does his job!!  Just keep the tailstock snug, and if there is a catch/stop just snug a bit.  Pretty short learning curve even for me.  Probably some videos out there somewhere.  
earl

[Arlin Eastman]

I have been watching Lyle Jamieson's videos.  In one of them he talks about turning rough bowl blanks.  I have always attached a face plate to the blank, but the problem is the blank being out of balance.  To combat that I've attempted to round the blank off on a bandsaw first.   This helps but isn't perfect because the blank can be different thickness at different points.  His method is to find the balance point between 2 centers on the lathe and then turn between a spur and live center.  I decided to try that last week.  It took a bit of work to find the balance point.  Also it seemed a bit sketchy to hold a blank without a face plate.  I let the lathe spin for a while before I was satisfied it wasn't going to fly off.   In the end it was safer than an out of balance blank on the lathe on a face plate.  So I think in future I'll be switching to that method.    A compromise could be to find the balance point, then come up with a centering jig that centers the face plate over that point.

Lyle taught me and some of the vets the same thing several years ago and that is how we have now been turning rough wood for 8 years now.

That is why I said in another thread it is faster to turn it then use a bandsaw.  I turn some knarley wood from the firewood and some of them just can not be centered but I get it close and then turn the bad spot off fast and go from there.

Also there are times I turn off the bad stuff and then rebalance it all again to get the grain I want to show the best.