Hinge slot in swimbait?

[KelpKritter]

I started using Azek decking, a PVC material, for the swimbaits I am experimenting with. I have two designs that swim nicely and I am happy with the overall design. I am using a pin and screw eye for the hinge but I cannot seem to cut the slot for the screw eye straight and uniform in depth. I have tried drilling multiple holes along a straight line and then cutting with a knife to clean the opening, rocking a drill bit back and forth, using a cutting bit on the Dremel. Nothing is giving me a clean opening. Any advice from those using PVC materials would be greatly appreciated. BTW I am trying to keep the slot inside the edges of the bait to better conceal the screw eyes.

DaveB.

KelpKritter

[gadawgs]

Not sure why the hole needs to be clean if it is concealed.:?That being said, you could try using a large drill bit so you only have to drill one straight hole for each screw eye.

[Vodkaman]

Ironic, I pretty much typed the same reply about 4 hours ago and then deleted it. I realised that it would not work, because you would be introducing up/down play in the hinge.

I agree, the concealment hides all the sins, but it would be nice to get the slot clean.

Try a dremel router bit, but still hard to control, better than a drill bit though.

Dave

[gadawgs]

Vodkaman, when I add my screw eyes I am concious of spreading them out far enough apart that the up and down play is very minimal. I am assuming that he is using multiple screw eyes per joint.

[BobP]

A Dremel fiber reinforced cut off disk should be able to cut a neat straight line.

[KelpKritter]

Thanks for the replys thus far. I appreciate the feedback. Let me go a little deeper into detail.

The baits are four segments. Segments one and two and two and three are held together with two screw eyes each, segments three and four have one screw eye. On the final joint if the up and down play is to great the tail section is all over the place and does not sit quite right. It needs to be pretty precise. Also, on each screw eye if the depth is to great in the hinge slot it changes the travel of screw eye on the pin which can make the bait to loose. As for concealment of the slot, it is not seen from the side, but if you inspect the lure it is very easy to see the slot and it is not clean or "professional" looking. I would like to get to the point of at least making my baits available for the tournament directors of the series I fish for the sake of raffle or tournament prizes so I want them to not only fish well but look like a quality bait.

By the way one of the problems with previous methods is that the PVC has a tendency to melt under certain cutting and sanding techniques. What I have tried so far would fall under these categories.

Thanks again for the help.

DaveB.

KelpKritter

[Vodkaman]

Forgot it was PVC.

Maybe you could burn/melt the slot in, by making a suitably sized metal blade, heat with a torch and push in. Tidy up excess with a sharp blade and emery.

Dave

[atrophius]

I am kind of new here, but have been playing around with the same thing. I have gone through a few trial and error. I started marking out the side profile of my fish I am trying to make. While your stock is square you can use a square to make the lines the length of your bait and see where your hinges will lie. I have used a file with some success. You can get a cheap variety pack of files at home depot if ya want to try it out. I just turn the file and use the side edge to work my way down the slot. Hopefully that will help, since our hinge will be lined out and the file cuts slow enough to check for straightness.

I have yet to finish a lure myself, but I am on the verge of it! Lots of playing around with hinge types.

I had thought about this earlier as well. Depending on the thickness of stock, I am going to try and use a compass on the top surface of the unshaped lure. I figure if I make this circle the same size as the thickness of the stock. It will give me a hemisphere joint line and a center point. That may be a way to gauge pin placements and joint travel on the eye.

Edited March 18, 2009 by atrophius

[mark poulson]

I also use PVC, and this is what works for me.

I went to a local wood working store, and found a Dremel bit that wood carvers use. It looks like a cylinder, covered in hard bristles.

I ground off the bristles on the very end, and kind of rounded over the tip bristles, because, otherwise, the bit tends to dig a deeper hole than I want.

I'm sorry, but I don't know the actual name of the dremel bit, but it's used by wood carvers. The advantage to using it, instead of a drill bit, to widen the slots, is that it doesn't tend to grab and drift like a drill bit. You still have to be careful, but it's much more "controlable".

I drill a 1/4" hole, centered where I want the slot to go, and then use the dremel and bit to make the slot wider, by gently leaning the bit toward each side.

I am not that concerned about too perfect a slot, or too tight a slot. I use D2T to coat the slots and joint faces after I've painted the lures, but before I do the final assembly and epoxy top coat, so I want enough play in the slot to allow for the buildup of epoxy when I coat it.

[KelpKritter]

Dave - Your idea of using heat has some merit. I fooled around a bit with the idea. I heated the screw eye and used it to make an impression in the material and it actually worked pretty well. It seems you can make a hole without actually removing all of the material. It seems to move the material and then hardens with the impression when it cools. It still needs some material to be removed, but I think I can work with this idea. Only down side is there was some charring of the PVC.

Mark - I was hoping you would chime in as you are using the same materials as I am. I will look for that Dremel bit. What is the hardness of the bristles on this bit? Are they totally rigid or is them some flex in them? The biggest problem I have been having is when the bit seems to 'grab' the material which causes the bit to wander.

Thanks again guys,

DaveB.

KelpKritter

[mark poulson]

Dave,

The bristles are actually steel, the same steel as the shank.

I was surprised at how little "drift" there is when I use it, especially compared to a drill bit. I do take my time, but it's pretty easy.

As for melting, I haven't tried that yet, but it sounds interesting. Just bear in mind that you're working with PVC, a plastic, which generates toxic fumes when burned. Do it outside, or with a respirator.

[Frank]

Well I do understand the look you are trying to achieve here .I was not happy with my first atempts either. I use a ball end mill from metal working. They are available in any size you could imagine. I chuck it up in my drill press and put the part in my vice mounted to the drill press table. My table has a cross slide so when I mount the part it can slide from side to side. The result is very good slots that look like they were cast in the part. This may sound like it is hard but it is very easy. The cutters vary in price but for a carbide cutter you are looking at about 10 to 12 bucks. The 4 flute design seem to be the best for my application.These cutters plunge cut and will cut sideways. So once you drill in you move sideways and done. If I could figure out how to use you tube I would make a video. Maybe I'llcall my son this weekend To help with this. Hope this helps.