Holding a plinth

[Tiger]

I'd like to make a plinth but want to finish the base off as well. It's late at the moment but I can't think of how I'd hold the piece so that I can do this. Normally with faceplate work I use a screw chuck or faceplate and screw into the workpiece and that's ok because the screw holes will be hollowed out later. With the plinth I won't have that luxury, so what would be the best option here, hot melt glue but is there a chance that it will stain the finish?

[tea lady]

Exactly how tall is this plinth? :think: I saw an artical about someone who held a bowl with double sided tape. They put a layer on BOTH surfaces and rubbed them down with the backing still on so there was a good bond, then stuck them together. Dunno how tall a thing can be turned in cole jaws. :think:

Or decide you are happy with a hand sanded finish on the ends. Here at 's those BIG turned side tables are done between centers with stubs that end up about 2 inches thick in the middle. These are then cut of and finished with a ROS.

Maybe an idea of the design you have in mind would help.:)

[rodent]

No the hot melt shouldn't stain the finish but i would glue the plinth to a face plate with a paper join and seperate with a chisel when finished PS. use wrapping paper not news paper .

[Tiger]

Thanks, Tea Lady and Rodent for your thoughts. The plinth is only an inch deep so not that high. I was thinking pretty simple design with an ogee curve. Only thing was that there wouldn't be much for a jam chuck to grip onto and hence my thread.

[Manuka Jock]

Tiger ,
Do the plinth in the same manner as a bowl.
Start with a wood length at least 30-40 mm longer that the finished plinth.
Screw you faceplate in with screws that do not go in to the wood deeper than half - two thirds the excess length.( the other 'half ' is your dovetail spigot) .

When you shape the spigot for the multi jawed chuck (using the compression mode) , scallop in deep enough so that you can flat sand the dovetail lip away as your final stage of work , and still have a concave base to the piece.

[Tiger]

Thanks, Jock for that, however the piece of timber I was planning to use won't give me the luxury of any waste (as it's only about an inch thick) so I can't afford to use screws.

[Manuka Jock]

Thanks, Jock for that, however the piece of timber I was planning to use won't give me the luxury of any waste (as it's only about an inch thick) so I can't afford to use screws.

You can if you glue a waste block to the wood , and screw to that .
In fact you can even waste block both sides so that both spigots are waste , and dispense with the screws altogether
I do it myself when I have a rare grained wood that I want to utilise to its fullest extent .

[RETIRED]

:aro-u: What he said.

[brendan stemp]

I don't quite understand the project but if you thought hot melt might be an option then go for it. I use it a lot and have developed a technique to ensure it holds very well. Basically the problem with hot melt glue is that it often cools too much before the two pieces being glued are brought together. This can be a result of a gun that isn't hot enough or simply because the first bead of glue cools down before that last bead is applied. Simple solution is to dispense the glue as needed and then reheat it with a hot air gun or even a blow torch. This gets the glue nice and hot and will provide a much stronger adhesion. To separate the two pieces of wood either cut the scrap wood off to as close to the good timber as possible and then use the hot air gun to melt the glue again. Or put the two pieces in a microwave. Any residual glue can be removed by softening it with hot air gun and turps. It will not stain the wood or fill the grain so a finish will not be affected by it.

[turnerted]

Tiger
I just finished a simple plinth off today, about 120mm diam. and about 40mm thick .
I just bored a shallow hole in the back with a forstner bit so's I could mount it on my long nose jaws in expansion mode, then shaped the top and side. I then mounted it upside down in my Cole jaws and tapered in to tidy up the recess .
Hope this helps .
Ted

[Tiger]

G'day Ted, I like your idea but I probably can't even afford a shallow hole in the timber that I have. As a matter of interest, how deep was hour hole?

[RETIRED]

There is another way that we used to do as well.

Turn a couple of waste blocks and use one on the headstock and the other on the tailstock with their drives and close up on the plinth block and drive by friction.

I am assuming that the block is parallel and all you have to do is an edge.

[colhu]

Hi Tiger

I would most likely do this with an aluminium ring out of a VCR hot-glued to the piece of board - heat the ring up on an old iron, apply the glue straight onto the face of the ring (rather than by using a gun), mark the centre of the bottom side of the board and position the hot aluminium ring with pliers. Then cool it out under a tap.

To get it off, heat it up on the iron again, pull the ring off, scrape the glue off while it's warm, and sand the bottom with a foam pad sanding disk.

cheers, Colin

[Manuka Jock]

Good thinking :2tsup:

[turnerted]

Tiger
The hole was about 3mm deep .
Ted