Advice on making a 3pc longbow riser

[Mitch Edwards]

Hey everybody my first attempt at making a riser here so I need all the advice I can get. I've gone through some how tos and read some on it but I'd like to know some of the little tips and tricks. What I've got is a 62" tomahawk 3pc that I can't stand the grip on and I'd like to bring down to 60". So I figure a 14" riser as the factory on is 16". I'm thinking solid phenolic so I don't have to worry about delaminations and also for strength. Again any advice is much appreciated. Thanks

[kennym]

You will gain about 3# (I think) by shortening riser.

Drilling the pins and inserts will be the hardest part, hard to keep limbs aligned without nice drill jigs. Then they have to match original maker's too. If you have to after drilling you can enlarge the pin hole and put wax on limb to keep from making a one piece, epoxy in riser pin hole ,then bolt limbs on in line. Rather not go that route, but have done it on a couple.....

Just make sure to get the bolt hole centered really well(and if need be make the riser block wide to start. Like if the limbs are exactly 1.5" wide, go wider on riser.)

Make sure 14" will accommodate the sight window you want.

You have a riser to go off of, so you are a step ahead of just creating one.

[Mitch Edwards]

Kenny I'm a machinist and we cut phenolic in our shop quite a bit so I know how it can be on tools. I'll be cutting the angles and drilling the holes on a bridgeport (knee mill) so I'm not to worried about that. I didn't know that shortening the riser would add weight so I'm glad you told me. The limbs are 60#@28 and I draw 28.5" so it should be stout! Is there any tillering done in the riser itself? Angle of the limbs? Or is it all I the limbs already?

[kennym]

I make all my risers exactly the same on both ends and tiller the limbs.

Shortening limbs 2" adds 6# on my D/R design, but from other folks reports , I get that shortening riser only adds 2 or 3 # .

You should be good on the drilling if the original is drilled exactly, and being a Tomahawk, I would think it would be very good.

Should be around 63 or 64# I'm guessing.

Not sure how much preload the hawk has , but you could lay the limb angle back a degree to keep the weight down. I changed 2 degrees on a test bow and it made 5 # . Buuut the limb nocks need to be ahead of the back of riser an inch or so if you can, or it won't have enough preload, will be slower and also noisier. The string needs this to be tight at the shot.

Check the hawk and see how much the tips are ahead of the back of riser.

I would probably rather trap the limbs a bit than fool with riser pad angle. My .02  

[Mitch Edwards]

Good info Kenny. I figure I'll keep the angle whatever it is. Thanks so much. Will be sure to post pics when it's done

[talkingcabbage]

I'm not gonna speak over Kenny -- he knows what he's talking about.  I'll just add my .02:  If this is your first riser, I would just go with the same length and angles as the current one, and just change the grip area.  That way you don't have all the other variables to work with.  Then if you still don't like it, change one other thing.  I know from experience when you start changing too much at once you can get something you never intended on dealing with.  Especially when you're talking pad angles.  You're gonna have enough troubles getting the limb bolt and pin holes right without throwing in the extra stuff.  Again, just my opinion.

[Mitch Edwards]

The hole positions I'm not worried about. If I have to I can bore them and indicate each hole to nail my positions. Kenny mentioned drill jigs and a good drill jig is accurate (I've made a few for shop use) but a bored hole is more accurate. The angles I will keep the same. Your right I don't wanna change to much. The grip definitely will be different though. Thanks for the input guys

[PEARL DRUMS]

Why not just rework the current grip?

[SportHunter]

I just looked over the Tomahawk TD riser on 3rivers, looks like you can get a new one for $360, not bad, especially when you figure cost of materials and the value of your time involved in the project. You could have them make a custom grip for you.

If your dead set on doing your own it would be much easier to shape the current grip to your liking. You could pike the limbs if you want it shorter but 2" is not worth it to me as the draw weight would go up and its hard to say if the smoothness of draw would be adversely affected. Once the limb length is cut you can't take it back.

[Mitch Edwards]

The factory grip has no meat on the thumb side of the riser and I want is a shelf to locate me thumb. I had planned on making it with a little higher wrist also. Any ideas on adding material to a riser? I'm all ears

[PEARL DRUMS]

Easy enough. Rasp a flat spot where you want to add wood. Then simply glue over-size pieces on the flats and re-shape to your liking. Your number one concern is a dead flat, gapless mating surface. The rest is easy. If you were closer I would help you through it.

[Mitch Edwards]

I really wanted to keep the factory riser in case I ever decide to sell the bow but that does seem a lot easier. And atleast that way I wouldn't have any unforeseen problems with the limbs. I'll have to think on that a bit

[kennym]

I'm bettin if you work in a machine shop and have the phenolic available , you will have little problem.   :D  

Have fun either way!  

[Mitch Edwards]

Thanks for the vote of confidence Kenny. One of the reasons I wanted to make a new riser is just to see of I could. I like to make things. Hell im at the shop more than I'm home. I think I might try my hand with a new riser and if it don't work out I'll modify the factory one. I think I can get a chunk of phenolic pretty cheap so if I scrap it then hopefully I'll atleast learn something from it. Thanks guys

[Mitch Edwards]

Well I got a piece of phenolic. I went ahead and got 16" in case I decide to go that same length. $73. Not to bad. Already got dowl pins and I'll make my own bushings out of stainless.

[kennym]

See, if you can make bushings, a riser will be a piece of cake...  :D

[Mitch Edwards]

I think what I'll do with the bushings is drill then bore from the pad side after I cut the angles. I'll drill though and then put a counter bore on the opposite side so I can make a bushing with a flange that will press in from the belly side of the bow. That way it can never pull out no matter what. I can then turn some plugs to press in over the bushings and after sand and paint they will be completely hidden. I hate relying on epoxy to hold. I've about got it all drawn up and planned out on auto cad. Bout the time my material shows up I should be ready to cut

[BrushWolf]

I always thought a bushing with a flange on it would be the way to go.

[kennym]

So Mitch, ya got that thing made ?  No pressure, but we wanna see it!!  

[Mitch Edwards]

Well Kenny the material came in Friday and in a couple hours after work I got it brought in to 2" wide ( 1/2" extra I know) and 14 long. Got the limb pad angles cut and all 4 holes put in it. I checked and the limbs mount up tight. Less play than the factory riser actually. Next step I'm guessing is mark out my pattern on it and get after it with the band saw. That extra meat will get mostly milled away but the thumb shelf may stick out a ways. Kinda like on some of the fedora bows I've seen. Not sure how to post pics so I may see if I can email them to someone and have them post them for me