• The forum upgrades have been completed. These were moderate security fixes from our software vendor and it looks like everything is working well. If you see any problems please post in the Forum Technical Support forum or email us at forum_moderator (at) aawforum.org. Thank you
  • February 2026 Turning Challenge: Cookie Jar! (click here for details)
  • Congratulations to Matt Carvalho for "Red Mallee Folded Form" being selected as Turning of the Week for February 9, 2026 (click here for details)
  • AAW Symposium demonstrators announced - If the 2026 AAW International Woodturning Symposium is not on your calendar, now is the time to register. And there are discounts available if you sign up early, by Feb. 28. Early Bird pricing gives you the best rate for our 40th Anniversary Symposium in Raleigh, North Carolina, June 4–7, 2026. (There are discounts for AAW chapter members too) For more information vist the discussion thread here or the AAW registration page
  • Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.

HollowForm inside???

Regis Galbach

Regis Galbach

Joined
Apr 10, 2017
Messages
86
Likes
27
Location
Mount Juliet, TN
I've never done a "real" hollowform until today (still working on it). I made an articulating arm this week and put a camera on it with a 19" tv monitor. Technically, it works but, I question how smooth I should expect to get it. Should I be able to get it as smooth as the outside and require little sanding? Or because that arm sticks out 8" or so from the rest is it inherently going to be rough and need very course sanding?

Thanks
Regis

camera1.jpeg
 
Depending on practice and skill level you might be able to achieve a fairly even surface on the inside from the tool.
If you are using a 3/16" cutter it is going to be rough ( until you get lots of practice ), a round carbide ( like a Hunter tool ) can leave a very nice surface, other scrapers will usually fall somewhere in between.
As far as what to do next,there are a couple of schools of thought.
One is to sand the inside reachable areas and perhaps the bottom. Places where an average person would see through the opening or feel.
Another is to make a collar of some nice wood that has a small opening that a finger would not fit through and leave the inside rough.
Still another would be to apply black gesso on the inside to make it 'dark and mysterious' and leave it mostly rough.
And finally try your best to sand the interior after carefully using a larger scraper to even the high spots out.
A few folks advocate putting some rough gravel or other sharp edged material on the inside, sealing the hole and letting the lathe turn at low speed for a while to "sand" the inside. Not sure how that works out.
Just my $.02.
 
I think that woodturners are the only people who worry very much about the inside smoothness. As Mark indicated, the smoothness is more a function of your skill level than your tools. It's really personal choice on how far you want to go on the interior finishing. I made a sanding-ball-on-a-stick using an old repurposed broom handle, rubber tape wrapped around one end to make a ball, Velcro on top of that and finally strips of Abralon to do the sanding.. I use this on really deep hollowforms and have a smaller version for hollowforms less than a foot deep. I've done the small hole and black gesso tricks. On one piece I used carvers rasps to intentionally make the interior much rougher and then used terra cotta colored paint.
 
Regis and I talked on the phone today. My first suggestion was to take very light cuts to sort of skim the top off of any undulations caused by the first hollowing. John Jordan taught me to take 2 or 3 cuts from the middle toward the outside and then pull the cutter toward you smoothing up those areas and trying to blend this into a previous cut. If you constantly make cuts from middle to left you often get a series of undulation kind of like waves in the wall thickness. By pulling the cutter gently trying not to push toward the wall you can take off the top of these "waves" and hopefully get the wall smoother. Then its just a matter of taking very light cuts to clean it up. It's still a scrape so it's never going to be really clean without sanding. I also recommended changed to something like a teardrop shaped cutter so you have a longer cutting edge to help smooth out the waves. On a vessel the shape he has you can clean up the bottom for a few inches with a hunter #4 or #5 by rubbing the bevel. You can clean up under the lip with one of his back cutting tools. The outer edges of both the top, bottom and side would require a different tool entirely. All of the ones I have that would reach this area are scrapers only.
 
Resist the temptation to stick your fingers inside a small opening to sand where a tool can't reach with the piece spinning on the lathe. You don't want to find out first hand how much it hurts when the lathe twists your hand around a couple turns.
 
Looking pretty good. That's a hard shape for your first one. The captured bar systems sure do help. I remember trying one of these by hand many many years ago. It ended up in the trash after I blew it up, like I did several before I finally got the hang of hand hollowing. Once I went to a capture bar system I never looked back.
 
You must log in or register to reply here.
Back
Top