Primitive Archer
Main Discussion Area => Bows => Topic started by: Morgan on September 04, 2018, 08:38:42 am
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I need help with the ins and outs of tip overlays. I have never done overlays before but am in a position where I would like to use them and they would be beneficial to the bow as well. I have seen overlays on here where the string groove is at or past the tips of the bow. This is the type I would like to put to use. The bow tips on the type overlay I’m talking about are ground down at an angle .
Is there a specific angle the tips need to be? Any input or advice would be very much appreciated. I’m approaching final tiller on the bow I’m working on, I have no nocks cut and the tips are rather skinny by my standard. To this point I’ve tight wrapped string at the tips for tiller string nocks, everything I’ve done to this bow is with the intention of using this type of overlay, now I’m to the point where I need the actual nocks to finish. The bow is pushing the working limit short and I need the string very close to the end of the tips. My fear is that I’ll sand the tips at an angle, glue the overlays on and the limb will split down the middle. Fear of the unknown you know? Overlays will be whitetail antler tine.
Any input is greatly appreciated... angle of cut, how far out towards (or past) the actual tips I can cut the nocks, etc.
Thank you
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I think you might be overthinking this a bit. The angle you grind the tip flat to accept the overlay is not that important. The glue area is. Make sure you have enough flat surface to glue the tip on and you will be fine. There are guys who glue static overlays on the tips so just go for it!
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also make the surface a bit rough and absolutely clean
i work with epoxy and it works fine for me
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Do a google image search for "primitive archer tip nock overlay". Many different styles of overlay. The type youre talking with the tip cut at an angle is pictured and most seem to have the groove about 1/4 inch short of where the limb tip originally was. The angle is quite shallow- less than 20 degrees.
As others have said-prepare the gluing surfaces meticulously. They don't have to be roughed up much (about 80 grit), but they should be perfectly flat and clean.
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Thanks guys.
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The lower tip give you an idea about the angle, it can be more or less, it all comes out the same.
I use either superglue, smooth-on or unibond, I never had a problem with one coming off except one time when I got careless and strung a bow with the string in only one side of the nock, the string split the overlay and the limb.
I fixed the bow and split limb with this;
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Here is a dry run mock up of what I’ve done. That is as flat and true as I can get by hand. Tip overlays are beautiful when done by an experienced hand, and I admire them, but the process stresses me out lol. The second I laid the tip to the belt grinder I thought oh no, I shouldn’t have done this. The bow is as short as it can be and the second that back came off on the tips it was too late to turn back. I’ve tried gluing to the natural back and cannot get the tips to blend seamlessly like I see in the angle ground ones. We’ll see.....
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Personaly i think that is a bit to much, but it should work just fine. Make that groove about halfwayish. Like its been said, you are making it to difficult. Make em pretty. Lol
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OOPs, wrong picture of the angle;
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Thank you for the picture Eric. That is what I had in mind but couldn’t visualize the angles. I should have stopped the grind halfway through the limb thickness. Dang. Hopefully I can salvage what I’ve done and make it look decent
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Your angle is more extreme than I would normally do (mine is usually more like Eric's) but your's should be fine. If you want to be safe. Don't put the string groove to close to the end of those overlays. You want to have some wood underneath them, if that makes sense. But if you have a good glue line it shouldn't matter too much. good luck
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A lengthy chapter - sized tutorial could be written about this with ease. I change the grind angle up to several degrees depending on the profile of the tip area... as in say, recurve vs. straight-ish longbow. And some of those degrees depend on personal preference.
Most important is matching the glue surface prep to the glue that is used. I use Smooth On epoxy, and prep both surfaces by grinding them to the angles and proportions I want, and then grooving them with a toothing plane blade so there's No Way the joint can be starved of glue. I cure them with shop lamps set close for warmth, covered with towels to hold the heat close. I've never had one fail. I'll try to post a few pics so you can see the angles, 'overhangs', and such.
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Thank you for the replies. I wish I had waited on replies to do the overlays. Very nervous that they will fail now. I havent finished the tips up yet, but wanted them glued in place so I can finish the bow this weekend. I used 2 ton epoxy and flattened areas with 40 grit paper hopefully it will suffice.
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You may still be fine. Don't worry too much. 40 grit and 2 ton may work good enough. Here's some pics, maybe they'll help with proportions and shaping and such..
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Ground...
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shaped
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String grooves on the belly because it's a recurve...
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That one has some overhang... ;)
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...
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...
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...
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... you see how they can basically be applied the same, but vary with flavor.
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Folks sometimes express concern about being able to see grooves from the toothing plane... see any? Me neither :OK They generally make for BETTER glue lines, not worse.
Just fyi, they can be had in various tpi. The smaller the teeth, the less visible they are, but even the moderate ones make practically invisible glue lines from any angle.
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Thank you so much for the many pictures. Those are beautiful overlay jobs. I think now that maybe I haven’t made a huge mistake with cutting my angle from back to belly. It’s a little more angle than you have but maybe not a huge mistake. Thank you again!
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I don't like to extend the overlay past the tip of the bow. Your depending completely on the glue joint to keep the bow together. I know some that have split the limb and I know some that haven't had any issues. It's the risk you take and the convendence in the glue joint. I take very little off the back of the bow and bring the belly up to the overlay. JMO
DBar