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7 February 2016

Experiments in making Luthier Spool Clamps

Yesterday I was desperate to do something... anything. It seemed like a good day to start my spool clamp project.


In case you're wondering what a spool clamp is... Take a look at this picture of Bill Loveless's spool clamps from Jake Jacobson's wonderful book: Hearts & Hands. A spool clamp is basically a couple of wooden spools on either end of a carriage bolt.


Having ordered a bunch of  carriage bolts, washers and wing nuts to hold it all together and some cork tiles to use as padding, all that was left was for me to make the spools. I'd did a little bit of research and figured I'd give a very popular technique a go.

Technique 1 was to use a hole cutter (pictured) to cut the spools. What an unmitigated disaster! You can see that I did manage to cut one spool before my drill overheated and died in my hands. My wood was a little thick so I was turning it over to cut from each side. I had a bad feeling about this method right from the off and should have listened to my instincts. Hindsight is a wonderful thing/

The spool I did make is a real mess. Having broken my drill, there was nothing left to do but to call it day.


 Well, I almost called it a day.

Technique 2 was born...

I did a little bit of digging about my garage and found an old hand-rail. It's not quite circular, but was pretty close to the 1 1/2 - 1 3/4 inch size I was aiming at. I chopped it up and sliced off a load of spools. I must say that this wood has the most horrible smell to it, but save the fact that the spools aren't round, this is looking promising. Unfortunately, having blown my drill, I wasn't able to put a hole in these spools to try them out. Pah!


Here's a shot of where I left things last night. I'd pretty much chosen to go with my hand-rail spools. 


Enter a bottle of Highland Park and a chance to reflect. I couldn't help but feel like I was cheating a bit by using the hand-rail. And another thing... the spools weren't circular. What could I do to fix this without resorting to a drill?

Sometime last night I dreamt up Technique 3... using my table saw...


Here's what I came up with... a spool jig that allows you to turn a spool on a table saw without chopping off your fingers. I knocked together this diagram this morning not thinking that I would actually go through with it today, but as you know, I'm a bugger when I've got a bee in my bonnet. 


This is the prototype. I have a spare drill, but unfortunately it doesn't fit in my drill press. This was all put together by eye. I think I got the jig part right, but I couldn't get the centre hole in the test blanks perpendicular. They're ever-so-slightly off, but I did get to prove what I set out to prove.

What you see above are two blocks which I've screwed to the plank they're standing on. There is a carriage bolt running through them that is parallel to the side of the plank (this is important) as I will use the side to guide the blocks to the table-saw blade.

The blanks are held in place by wing-nuts on either side. The key thing here is that the carriage-bolt can be twisted to turn the blanks.


Here you can see the first cut made with the blade. I've allowed it to cut the base of the wood, but this is as far I will push it. At first with a lot of wood to cut in each pass, I was careful take my time and keep stopping to reposition the blank on the carriage-bolt. 


After a while I managed to get a crude circular spool shape. At this point I pushed the jig so that the spool was touching the blade and then slowly turned the carriage bolt by twisting the near end of the bolt (furthest from the blade). 


Here's what the spools looked like after the final turning. It's still a little rough around the edges, but I reckon that if I'd topped and tailed the blanks with some waste wood, that this could be avoided. The big problem I had here was that my centre hold isn't perpendicular to the spool faces. If you look closely at the picture above you'll see that the washer is slightly tilted. I'm convinced that better holes would have resulted in better spools. 


Even with the slightly off spools, you can see that these ones are still usable. I obviously haven't stuck anything to the inner side of the spools to protect the wood, but you get the general gist of how these clamps are meant to work.

My thinking is that I will have a go at turning a couple of the hand-rail blanks to see how they will come out.... but not before I can get a new drill-press that fits my spare (and now, only) drill.


Before I go, I'll show you a new gadget I tried out today.

When I posted this photo on Google+ I claimed that it is a bullet for my elephant gun, but no, it's actually a pin punch for making holes to start your drilling off. Previously I would have used a nail or a screw for this, but this works great! It's so simple that it immediately gets you wondering how on earth it works. You press down on the pin, pushing it inside against a spring. At a certain point the spring is released, firing the pin back out to make a tiny depression. How did I survive before without it?

Check out this video from ghostses for a fascinating insight into how this little gadget works:



Okay... one last picture of wood. I picked these up today and intend to make two carver's mallets out of them (heavy and light). I know I'm meant to be using hard-wood for this, but I reckon I'll get away with it. Famous last words! ;-)

That's a project for another day... I've got projects coming out of my ears at the moment. Just the way I like it! 



I leave you with a rendition of Folsom Prison Blues. As well as being a top version of the classic tune, it's also a great reminder of the story that hit the news this week about the discovery of a new type of tarantula that's been named after Johnny Cash.

Aphonopelma johnnycashi was discovered among the foothills of the western Sierra Nevada mountains near Folsom Prison. Die-hard Johnny Cash fan, Dr Hamilton named the species after his hero explaining that "the males are predominantly all black, so it fits his image." He then went on to explain that he has a Johnny Cash tattoo.

I bet it's not as good as my Freddie Mercury tattoo. Ha ha.





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