Why use a heel cap?

[Brian B]

‘90 A5-L on the left, ‘87 Flatiron F-5 on the right. Why does the Flatiron use the heel cap instead of extending the back up instead? Something to do with beefing that area up?

Thanks.

[rcc56]

A heel cap is easier to build and requires less labor.

[Rob Roy]

That area of the neck is under an extreme amount of tension. Extending the back over the heel locks it in solidly and negates the possibility of that part of neck joint opening up at all in the distant future. A good design longevity-wise. Bending the binding into a tight curve is the only real hassle in that design in my experience. Designs with a bolt on neck use the separate heel cap because they mass produce necks and rely on the mechanics of a bolt/insert instead of a dovetail to keep the joint tight.

[HoGo]

I guess the Flatiron has bolt-on neck (perhaps bolted after finishin like on guitars) while the other one is glued tenon or dovetail.
Sorry, missed the previous response about bolt-on...

[sunburst]

...negates the possibility of that part of neck joint opening up at all in the distant future...

I'm not so optimistic, especially after 30 years of repair work.

[mirwa]

Old school method of extending the back over the heel leads to a super strong joint, violins, cellos and dbl basses still use this method today.

New school method of making the box and making the neck and putting a decorative cap over the heel relies on a well fitted tenon to hold the neck on.

Steve

[rcc56]

Extending the back over the heel indeed adds some strength to the joint, although I have seen several let go over the years.

Back to the original question-- Why one style on the A5-L and the other style on the Gibson made Flatiron F? Who knows??

It might have been that [so far as I know] Flatiron F's always had an uncovered heel, even before Gibson bought the company. It might have been that Gibson wanted to use the same appointments on the A5-L as on the F5-L. It might have been to reduce costs on the Flatiron so they could sell it for less, or to distinguish it from the Gibson.

Or they might not have been thinking about it at all.

Apparently they weren't thinking about structural integrity, or they would have covered the heel on both models.

[Brian B]

I’m pretty sure it’s not a bolt on neck on the Flatiron.

[rcc56]

Sorting out the different neck joints used on Gibson-made instruments made after 1970 is more work than I want to do. I know that they have changed them several times on both their mandolins and their guitars.