Riser Separation and Replacement

[PatM]

If using all lams a power lam between the back and belly at the handle will prevent the handle area from flexing, keeping the riser from popping off. If you are only using a back and belly leave enough thickness at the handle of the belly to keep the handle area from flexing.

What keeps the power lam from popping? Its length? After all it's just held on with glue too.

It's the accumulation of thickness that adds up to a stiffer midsection.

[Dances with squirrels]

"Bend too close" is another way of saying the flexing of the limbs isn't gradually and adequately quelled before the handle by the design and execution of the dips/fades.

Can the bond be stronger than the wood? Sure.

[mikekeswick]

Well Mike, that's not the only "well known fact" in bow making that I've found to be something else, so call it that if you wish, but calling it a fact doesn't make it one.

If we're going to have a fair conversation about this, a few things should be noted.

Toothing plane blades are made in a variety of teeth per inch. So yes, the most coarse ones would show their effects at the fadeouts of their joinery. They could be made perfectly smooth, but would be visible unless they were dyed or otherwise hidden. BUT, the irons with more teeth per inch leave glue lines that can be invisible if the pieces are well mated. I made the danged things so know right where they should be, and sometimes I can't find those glue joints myself. Same with horn tips, overlays, underlays, and such. Ugly blend? No. There are NO ugly blends on my bows and I wouldn't use them if that was the case.

By the way, someone mentioned draw weight... I've made bows like this with draw weights over 70 pounds... no pedastals, no powerlams, flexing well into the added handle pieces... glue lines still as tight, tidy, and hard to discern as the day I made em. Just sayin'.

Smooth On is made to flex and maintain the bond. It holds flexing limbs together just fine, right? In fact, I have used the toothing plane on countless, flexing full limb joints without a single failure. So it obviously isn't "the flexing" of an added handle piece that causes the joint to fail. Imo, most commonly, poorly designed or executed transitions from handle to working limbs are the cause... which is to say, halting the flex from the limb too abruptly. So it may be more accurate to say then that a non-flexing handle is the cause, not a flexing handle. Toss in another issue like a joint a bit starved of glue, or not enough working limb or limb taper, etc, and off she comes. The use of a toothing plane to prep the joints simply helps swing the odds back in our favor a bit by creating more gluing surface and making it practically impossible to starve the joint by clamping. Not a cure all, but a big help. If we add to that a good design and a smooth transition, the handle piece can flex and stay tight... and that's a fact. 

Yes I know saying something doesn't make it a fact
When I started out with lam bows I made this mistake myself a few times - therefore it isn't just what I am saying - it is linked to my direct experience and as I'm sure you know many other peoples experience. Judging by the amount of times this question has come up over the years it isn't 'just me' making things up.
Yes I know about toothing planes but you didn't mention what tpi you where using. I'm glad you make nice transitions If a fine graded iron wasn't used you would see the joints - that is what i'm saying.
Draw weight makes no difference if the design is correct for the weight.
Virtually any epoxy will flex. Yes the limbs stay together but the forces on the gluelines in a limb are not the same as the forces on the glueline/s on a riser placed on top of a limb stack....comparing apples to oranges No is isn't JUST the flexing it is the combination of flexing combined with the riser ending on a working part (if designed incorrectly). Of course staving glue joints will causes problems, as will a bad tillering job BUT that isn't the issue I was talking about. To not starve a joint of glue just don't tighten the clamps too much! A toothing planed joint with over tightened clamps will still be half starved...
One thing I will say because it was implied above is that I respect anybody and everybody who makes bows of any quality and was not meaning in any way shape or form to degrade yours or anybody elses work. Nobody is perfect....most of all...me.

[Badger]

   Mike, my experience is very similar to yours. Not bragging but I have done hundreds of lam bows and boo backed bows. Sometimes a couple of hundred per year.

   My preferred woods are osage, ipe, massaranduba, and even though it chrysals I like to play with jatoba. The white woods I have done plenty of also but less frequently.

   I look at it like this. If I have a 5/8 slat of osage that I am gluing a boo back on and an 8" riser block I don't like to go over about 64" long and 50#. I much prefer to use a 3/4" belly slat. Massaranduba is the same as these woods are really not what I call stiff woods.

  Ipe is a bit stiffer and I will tend to go heavier or longer with a 5/8 thick belly slat but I still prefer at least 3/4 or close. If I feel I am marginal I will usually use smooth on but normally use tightbond 3. Multi lam bows that run the belly slat over the fades into the handle are far more secure but I seldom do that. Instead of power lams I will very often just use thicker boo and taper the thickness toward the tips seems to work well.

[Dances with squirrels]

Relevance is in order in these discussions, or there's no sense having them. The shortest added on 'handle piece' I've glued on was a 9" piece.... and I was really trying to conserve length on a blind bow, on a boo/yew/osage trilam, 58" ntn, 58# @ 28", d/r... and I'd bet the bow itself that it isn't shaped how most folks would shape it. I've glued the handle piece on other such bows, albeit longer ntn, up to 15" long, but usually they're at least 11-12" long.

Heck, who knows if we're even talking about the same kind of bows here. Probably not.

Bottom line is, there are many considerations and tradeoffs... handle design, thickness, width, shape, fade length and shape, limb cross section, limb action, working limb length, and more... should help determine what length piece we decide to glue on for the handle area. If we don't pay heed to such considerations, we'll learn to... or our bows will suffer their consequences.