forward riser advice

[savage1]

Here is an old project with a new aporoach. This is my belly mount I am trying to convert to a front loader.

My concern is with riser strength. The stripes are going to be four layers of .030 glass. each.

What do you think? Any advice is welcome.

Lou

Looks like I need help posting pics.

[MoeM]

Yep pics would be usefull...

[Troy D. Breeding]

Finally got the pics uploaded so I could help post them for Lou.


 

 

[macbow]

I think with the grain in that wood there is little strength.
Adding the 2 pieces of glass will be what gives it the strength and should work. Need a really good glue like smooth on.

[Troy D. Breeding]

Not sure if your going to use this exact piece of wood or not, but I sure wouldn't consider it with those knots in the sight window. Even with the glass in the riser the knots are totally in the wrong spot.

Troy

[savage1]

Thank you Troy.

The riser is a dummy out of plywood just to give me an idea of a rough geometry.

Putting in glass after Shaping is beyond this cobbler.

I drew the stripes in so you got the idea. I was just wondering if the general design scared anyone.

There no valor like that of a fool. I've had a riser fail before but it didn't have glass at all.

Lou

[NYArrow]

Nice looking bow! Hope it does well in aution!

[beachbowhunter]

That shape makes me a little skittish. You might consider doing a sandwich lam with some G10 glass in the middle, or stacked phenolic like the Little Suckling recurves that have so much deflexion.

[savage1]

If it doesn't bust my head open in the event of a failure, I will get some G10. For now, trying to keep from any more work into it.

At least I'm. Not alone in the skepticism. But if it holds it will shoot just like another bow I made out of scraps. Turned out to be my favorite to date but riser was only intended to give me some numbers and Would probably blow if shot regularly.

Lou

[Crooked Stic]

I think an ibeam would be stronger. But if you don't want that then a couple of pieces glass on the front would add  strength to the shelf and window area.

[savage1]

I like beam construction too. So you think a beam instead of the glass stripes would be strong enough or do you mean in addition to the stripes?

[heartlandbowyer]

An I beam will be stronger than your glass stripe design. However it looks to me like you have more than enough meat left in the riser to be structurally sound. Think about how little material there is in the throat section on many of the Bowes made out there. Circumferences around the throat on many bows is less than five inches.

Use a dense hardwood and you will be fine. For pieces of mind for you throw your glass strips in. And for more insurance get ahold of big Jim I'm sure he will custom cut a piece of glass to use as a ibeam, looks to me like you'll need a piece around 3.5 in deep for your riser design.

Good luck keep use posted.

Cory

[Greg Szalewski]

That looks interesting Luis. I will want to give that a test drive when you get it done. Keep us posted on the progress.

[savage1]

Greg,just the guy I'm Looking for. I lost my phone last week. Send me a text so I can get your no.

Lou

[ChuckC]

I am thinking that if you use the right piece of wood, it would likely be fine for bows under, say, 60# draw.  If you add "internal structure" it will stiffen and strengthen it better.  "I" beam (sandwich)using three pieces, or similar using a laminated board (Diamond wood and similar) looks to be better.  Using glass inserts along the "lines" you drew should strengthen and stiffen it also.

How about a Diamondwood (or similar)or phenolic center portion and pretty wood outer (from your drawing)separated by lines of contrasting glass or phenolic strips ? ?

Then let Greg shoot it first. . . .    

ChuckC

[savage1]

I always try to find someone else to "break in" a bow.

Lou