Riser failure

[buckeyebowhunter]

Ever seen a riser fail like this? I'm scratching my head on this one. Bow is over a year old with several hundred arrows through it. The gentleman I built it for said he wasn't even shooting it when this happened, thank God.

[Mad Max]

That stripe is in a bad place, bummer
Looks like it de laminated  on you

[Longcruise]

Maybe a bit deep into the grip.  Hard to tell looking at it on a phone.  What was the draw weight?

[Crooked Stic]

Not enough meat in the throat plus the accent looks to be shaped thru on the front been better to ibeam.

[buckeyebowhunter]

Mike thanks for the advice. Didn't really think to I beam using the dymondwood and actionwood. Man this hurts my soul.

[buckeyebowhunter]

Draw weight was only 50#

[jrstegner]

I had one so that. It was also action wood, and too deep in the throat. Action wood isn't that strong. I don't care for the looks of I beams. I haven't had any trouble with overlays on the back and a 1.75" deep grip.

[Crooked Stic]

A couple of glass overlays on the front can add strength also as long as you don't shape thru them.

[jess stuart]

I put three layers of glass across the back of the riser.  I started that practice years ago.  I have not had one failure since.  Before well not so much.

[buckeyebowhunter]

Appreciate the input fellas. I am going to start doing overlays immediately. I'm tempted to ask for risers back that ppl have. Scares me to death.

[Mad Max]

You need to make some kind of pattern sander for more options on the look of your risers. Stronger too.
here is a template to make one of my riser.













Mine is a Ridgid Oscillating Edge Belt / Spindle Sander, I bought the floor display for $100.oo and made this.














Here are the pieces I made when I still had my Machine shop, 1/2" shaft with 2 roll pins and 3 flat's so it wouldn't spin in the drill chuck, a rub collar, 3/4" thick plate 6" wide, hole for a bearing. The 24" long sanding belt works much better than a 2 or 3" spindle sander. spindle sander will clog up fast.



Crooked stic made a nice one on his edge sander with a 80" long belt

[Kirkll]

Ever seen a riser fail like this? I'm scratching my head on this one. Bow is over a year old with several hundred arrows through it. The gentleman I built it for said he wasn't even shooting it when this happened, thank God.

Those straight accents are plenty strong enough.... But.... Sanding through them and leaving end grain open on the back side of the bow should never be done without putting overlays on it. I've seen this happen a lot.

Sanding through the belly accent lines isn't as bad, but it could still separate on you if your have too much riser flex..... Depth on the grip should never be less that 1.75" and going less than 4.75" in circumference is pushing your luck on bows over 50#.   

There are different grades of action wood out there too. I wont use the standard low density stuff at all myself. I use a product called ChromaPly that is a high density lay up with very thin laminations that the birch they use is fully impregnated. Seriously strong stuff with very little flex at 60# ....

But  Anything i build over 55# i use a G-10 I-beam, or a good hardwood I-beam assembly. If you don't like the looks you can off set it though the strike portion of the riser, and still do a footing or straight accents.
check these out..  These both have 3/16" G-10 I beams that are offset

[buckeyebowhunter]

Max thanks for the post. I am going to eventually make some flared risers, unfortunately at this point my shop is pretty limited, My only option would be to use my robo sander for pattern sanding and I'm not sure how well it would do for patterning a footed riser(also time is another issue).
I've seen you post your rigid setup before, that is a slick sander and I thank you for the tips and ideas.

Kirk, thank you for weighing in. I was interested to see your thoughts on my post. I understand the positives of an ibeam. But I don't understand how they can be anymore beneficial on a piece of dymondwood which is pretty much a bunch of mini I beams? I will no longer be using that action wood as an accent stripe, but I've built several bows with that same type of stripe with no issues thus far.
Max and Kirk, beautiful bows by the way. I love seeing your guys' work and hope to make it there someday with my bows.

This has been my first failure, and hopefully the last. I will say that on this particular bow I did sand into my accent stripe. I guess it did not cross my mind that a glue joint could fail from having sanded through it there, but it all makes sense now after hearing your thoughts. I'm glad it happened the way that it did, also the customer was a friend of mine so it worked out well in that sense.

I will chalk it up as a craftsmanship flaw, but I also know that shtuff happens, I've even seen people post pics of machined risers broken, so I know it can happen.

[Kirkll]

No worries…. You are right… chit happens and you learn. When I first started doing footed risers I did them all by hand using a band saw to rough them out and built jigs that I used on a little ridgid sander like this one… I went through two of these sander’s before I got serious and up graded to an 80”x 6”  edge sander. ( game changer right there)

But I’d highly recommend one of these little sanders for guys just getting into building bows. You can use it for a spindle sander and an edge sander both.


https://www.amazon.com/Ridgid-EB4424-Sander-Oscillating-Edge/dp/B0015B9G0S/ref=sr_1_1?crid=1IXT80J1SHCKC&keywords=ridgid+spindle+sander&qid=1691333694&s=hi&sprefix=ridged+spindle+sander%2Ctools%2C175&sr=1-1

The S shaped footed risers can be very challenging fitting everything by hand. But before I set up a pattern sander bearing on my big edge sander, I got pretty creative with jigs. I even set up a big two hp router and used large straight cutter bits with flush cut bearings to do these footings…. I wouldn’t recommend that rabbit hole after my experience with it… a pattern sander is much more forgiving, and you don’t get tear out like you do using cutters. They are also much safer…

Running a big 2” straight cutter on a shaper or large router is kind of spooky… one slip and it gets ugly real fast. Fortunately I had no such injuries, but have seen others get tangled up in shapers before.., not pretty…

It takes time and money to accumulate your shop machinery, and you can easily screw things up with the upgraded tools too. Just faster… lol

[Crooked Stic]

Yep I thought I was gonna be cool and use a router with pattern jigs. Until doing osage and it tore a piece off and slammed the wall with authority and had sore fingers for awhile.

[buckeyebowhunter]

Thank you guys for the replies. I have made several risers that I have shaped very close to the accent stripe. Do you think I should expect them to be compromised at some point as well or do you believe they are okay since I did not go through the stripe. I am contemplating asking people for their risers in order to reinforce them. Some are several years old, My personal bow is like that and is about 65lbs and probably 4 years old with probably thousands of arrows through it. Maybe I'm just gun shy at this point.

Kirk I am going to order one of those rigid sanders. I was already on the fence about it.

[sman]

if you have a drill press you can get one of these

https://www.stewmac.com/luthier-tools-and-supplies/tools-by-job/tools-for-sanding/robo-sander-flush-trim-sander/?utm_source=google&utm_medium=shopping&utm_campaign=2023-08-gp&utm_source=google&utm_medium=cpc&utm_campaign=&gad=1

[Kirkll]

Thank you guys for the replies. I have made several risers that I have shaped very close to the accent stripe. Do you think I should expect them to be compromised at some point as well or do you believe they are okay since I did not go through the stripe. I am contemplating asking people for their risers in order to reinforce them. Some are several years old, My personal bow is like that and is about 65lbs and probably 4 years old with probably thousands of arrows through it. Maybe I'm just gun shy at this point.

Kirk I am going to order one of those rigid sanders. I was already on the fence about it.

I built a lot of bows with those little combo edge sander/spindle sander units. You cant beat the price. Get some 36 grit sanding belts , Zicronium if possible.  I can send you a few 36 grit spindles that are 1.5" . if i remember right they have multiple size spindles, and one is 1.5".... The only thing i didn't care for on those things was they ocellate up and down.... i often wondered if i could disconnect that function on one of those.

Doing overlays on those risers you sanded through the accent lines would be good insurance. I'd definitely do it on a 65# bow. Having a riser snap at full draw at that draw weight could put a serious knot on your gord if not injure yourself seriously.   Kirk

[Kirkll]

if you have a drill press you can get one of these

https://www.stewmac.com/luthier-tools-and-supplies/tools-by-job/tools-for-sanding/robo-sander-flush-trim-sander/?utm_source=google&utm_medium=shopping&utm_campaign=2023-08-gp&utm_source=google&utm_medium=cpc&utm_campaign=&gad=1

I wouldn't waste time or money on those things myself. too much flex and they burn through sanding sleeves to quickly.  Those drill presses are not designed for that type of pressure either. Especially a cheap drill press. You'll take the bearings out of it pretty quickly.  You would need a heavy 18" vertical milling machine to put that kind of lateral pressure on the chuck. The mills use collets too .      .02 cents

[buckeyebowhunter]

Kirk thanks for the response. I actually have some 36 grit sanding sleeves for my spindle sander (grizzly) but thank you for that generous offer.

I don't know if I can add overlays to the front of the entire riser without sanding through more of my accent stripe just because of the way I have them rounded over. I'd have to hack off quite a bit just to get them flat to glue the overlay onto. I think I have enough meat in the throat section to get overlays if you think that would add any insurance. If that makes sense.

Here is a pic of my personal riser and you can see where i mean that it is probably too round to sand. It is a 65# bow. It's about 3 years old and no problems thus far.