Another? hold-down method

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jfederer
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Another? hold-down method

Post by jfederer »

This is the second set of top caps for my light fountain projects. They fit exactly into 50 MM OD Acrylic tubes which house the spiralled LED ribbon. Both sets are cut from a baseball bat blank of hard Maple. The first set I cut tall enough to screw each to the spoilboard using 4 diagonal screws at the base. This time I didn't have that extra height. After considering a custom jig, I said to myself, "Self, modern wood glues are stronger than wood. Let's see if that's true." So I cut a piece of 3 mm plywood and glued the cut blanks to it. The blanks are vertical grain, so I wasn't sure that the end-grain glue line would be very strong. Some other things came up, so the glue set for a couple of days.

The profiling passes used a 1/2" EM with a 6 mm DOC per pass. There was a bit of chatter on the initial profiling pass at the top. In the end, the glue joints all held. I cut the pieces off at the bottom step then finished the top shaping on the lathe.

Why didn't I just do everything on the lathe? Accuracy. I shaped the tops artistically, where accuracy doesn't matter. The fit into the central dowel and inside of the acrylic cylinder need to be accurate.

So if you need an alternative to the blue tape method and don't mind sacrificing a bit of material, I recommend this approach.
GlueClamping1.jpg
GlueClamping2.jpg
Joe Federer

www.fabrikisto.com incl. Tailmaker software
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scottp55
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Re: Another? hold-down method

Post by scottp55 »

Nice Joe:)
Did read about it in Shopbot forum(and some variations);
http://www.talkshopbot.com/forum/showth ... Down-Trick

I've used gel CA on a carrier board for wet Birch and White Oak burls too for .25 and .5" BN cuts.
A really good whack broke them loose for flipping and skimming excess.
5.18.18 BB FINAL DEPTH UNSANDED 4.jpg
8.6.19  SMALLEST OAK BURL TOP CARRIER BOARD.jpg
8.10.19 WHITE OAK BURL .5 INCH DEEP 1.jpg
That project...nearing your exacting standards?
scott
I've learned my lesson well. You can't please everyone,so you have to please yourself
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Leo
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Re: Another? hold-down method

Post by Leo »

Nice Idea - I like it
Imagine the Possibilities of a Creative mind, combined with the functionality of CNC

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martin54
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Re: Another? hold-down method

Post by martin54 »

If you think about it there are a lot of different hold down methods, I tend to use different hold down methods for different projects :lol: :lol:
Have to be honest though & never thought about using wood glue as a hold down method :lol: :lol: Used hot melt glue when shimming a piece to machine the first side & CA glue with tape.
Another variation with these parts might have been to use screws up through the spoilboard from underneath if of course you have access to the underside of the spoilboard :lol: :lol:

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jfederer
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Re: Another? hold-down method

Post by jfederer »

martin54 wrote:
Wed Jun 30, 2021 11:48 pm
Another variation with these parts might have been to use screws up through the spoilboard from underneath if of course you have access to the underside of the spoilboard
I thought of trying that. My spoilboard is sitting on a combination T-track and Vacuum table. I would have had to raise the spoilboard (held down at 4 corners with brass T-bolts hooked into the T-tracks), run screws up into the parts, etc, etc. Far easier just to glue the parts to a piece of plywood, which I then screwed to the spoilboard as usual.
Joe Federer

www.fabrikisto.com incl. Tailmaker software
www.federer.ca

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martin54
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Re: Another? hold-down method

Post by martin54 »

jfederer wrote:
Thu Jul 01, 2021 2:20 am
martin54 wrote:
Wed Jun 30, 2021 11:48 pm
Another variation with these parts might have been to use screws up through the spoilboard from underneath if of course you have access to the underside of the spoilboard
I thought of trying that. My spoilboard is sitting on a combination T-track and Vacuum table. I would have had to raise the spoilboard (held down at 4 corners with brass T-bolts hooked into the T-tracks), run screws up into the parts, etc, etc. Far easier just to glue the parts to a piece of plywood, which I then screwed to the spoilboard as usual.
I have an old Gerber system 48 modified to run on more modern electronics.
My table is made from Aluminium slats about 4 inch wide, the slats have a channel in the edge for T bolts.& are spaced about 3/8" apart on top of that I sometimes put a sacrificial board but not all the time. I've run screws up though the gaps between the slats in the past but it's not the best method as it's awkward getting under the machine :lol: :lol:

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