Forms, tapers, and glue lines

[onemississipp]

When building a form for a bow that uses tapers, say .003, do you use .003 of reverse tapers on the form to make parallel? This should give better glue lines, right?

[jess stuart]

I know Binghams suggests using a reverse taper on the form.  I never have and haven't had any issues without it.  I just figured the hose would easily make up the difference.

[bigbob2]

ditto the above.

[Bowjunkie]

Same here.

[LittleBen]

yeah sounds like a relic from the days prior to the hsoe method .... if there ever was such a time.

[onemississipp]

Thanks guys!

[7 Lakes]

It doesn't matter for the limbs but when fitting the riser.. .003/" isn't much of a error but it is an error.  It does show up on a Hill Style with a .006/" taper and is well worth using reverse tapers on the form.

A perfectly flat 14" riser placed on a flat Hill Style bow form with a stack of .006/" taper will be off .042" at each end of the riser. That's .006 x 7" on a 14" riser. This can be absorbed with thick glue lines but a reverse taper is a pretty simple fix.

[Bowjunkie]

I don't think I've ever made a perfectly flat riser, but yeah, reverse tapers would help on those.

On d/r bow riser blocks, the fit to the taper of the lams and press is figured into the riser block shape prior to glue up so that when everything is stacked up and pushed down onto the press, everything fits tightly together.

[jess stuart]

I never thought about the flat riser, I make take downs almost exclusively. If using the flat riser then they would certainly be a good idea.  Thanks for pointing that out 7 Lakes.

[monterey]

Jess, my bows have all the tapers above the riser so therefore the reverse under does not seem to apply to them.  Have always thought that if I build any style with a taper under the riser that I'd offset it with reverse tapers to make sure the riser fit properly.

[Jason Scott]

I've never compensated for the taper and haven't had a problem with glue lines at the riser fades. I've done some .006 forward taper layups.

[ChuckC]

So why taper if you are gonna reverse taper to make up for it ?  Doesn't one just undo the other ?  Why not just make a less severe taper in the first place, like .002 ?

ChuckC

[bamboo]

chuck
the reverse taper is not in the stack--it is used as a shim on the form---