|Project by socrbent||posted 02-27-2016 05:06 AM||969 views||4 times favorited||10 comments|
My name is Gene and I’m a rookie segmenter. The purpose of this jig is to assist glue up of half rings for segmented turning. Getting a band clamp to fit my first segment ring didn’t work for me. I had purchased a variety of sizes clamps at the local big box. However none would fit my first ring. So I used slip glue method to assemble it in 2 halves them glued them together. I liked the idea of half rings, but wanted a way to make them under clamping pressure. Hence this first effort at a clamping jig that is adjustable for different sized rings and uses a lever to apply pressure . The jig was completed this evening, seems to work for a dry assembly, but has not yet proven itself under pressure :). Your suggestions for improvements or problems you foresee when I do a glue up are most welcome.
Photo 1 – Overhead view with half ring clamped
Photo 2 – Back side view – note the clamp is loose so the band is drooping
Photo 3 – Test of addition of mdf top board to hold assembly flat while glue dries
Photo 4 – End view showing rabbiting in top and bottom mdf pieces and the jig clamped in vise which helps hold jig while pushing on lever (real leverage) and access for flattening clamping shown in photo 3
Photo 5 – Bottom view showing attached block for clamping in vise
Photo 6 – Under the hood – showing clamping lever, pivot bolt, band slot and movable band anchor. This photo was taken prior to final assembly and doesn’t show the band attached to the lever with a screw
The jig works by adjusting the left side band anchor by releasing top pressure, sliding the band anchor block in the rabbits to set the the ring diameter from band slot on right. Tighten top pressure screws. Place the segments inside band. Dry test clamp with lever and wedge. Adjust as needed. Apply glue to segments. Tighten clamp with lever and wedge. Clean up glue squeeze out. Clamp on top board if needed to force half ring flat.
Wedge to hold clamp arm under pressure.
Wedge in place holding lever tight
When assembled the oak block on the left end of band sits in the rabbit and can be slid in slot to adjust for different diameter rings. The band is attached to the block by a screw. The oak block on right is glued in the rabbit and has a slot just wide enough to keep the band at the proper diameter for a half ring. Band slides through the slot and is attached to the lever.
This shows the mdf board used over lever with its rabbit.
While typing up this description, I’m beginning to think the jig maybe an overly complex solution to a simple problem. Guess I’ll find out as I use on my first segmented bowl.
-- socrbent Ohio