I think I screwed up big time!

[raulblack]

I started building my first guitar yesterday (KMG Success Kit w/ Mega-Mold). Everything seemed to be going along fine, when I realized, I have a big error. I glued the neck and end blocks to the sides, flipped over the sides, sanded the top flat, and glued the top kerfing. Then I realized the end blocks are not square with the Mega-Mold. IOW, I took way too much (maybe 1/32") wood off the top inner edge of the neck block when truing the top rim.

Since I didn't remove much (or any) wood from the outer edge of the block (where it mates to the sides), I believe I can glue (laminate) a super-thin piece of hardwood to the top of the neck block, and re-sand the top rim. But even if this will work, I'm clueless about what went wrong and how I would keep the sides at a 90-degree angle compared to the base of the Mega-Mold.

Here are some photos to better describe my problem:

After gluing the blocks and putting the work top-side down in the Mega-Mold, everything seemed perfect. The blocks appeared to be at a 90 degree angle to the Mega-Mold. After flipping the sides over, I realized the top of the neck block was too high at the inner edge even though the height of the outer rim is consistent all the way around the Mega-Mold base. Confused, I eventually decided to sand the protruding portion of the block down in order to match the height of the rest of the top rim

NeckBlockSandedFlat.jpg (41.71 KiB) Viewed 5776 times

After gluing the top kerfing, I realized what the problem is, the neck block is not square to the base of the Mega-Mold.

NeckBlockNotSquareToMegaMold.jpg (50.34 KiB) Viewed 5776 times

The tail block is not square to the base of the Mega-Mold either.

TailBlockNotSquareToMegaMold.jpg (47.01 KiB) Viewed 5776 times

I would greatly appreciate any advice that might help me to recover from the mess I've made before I proceed.

Thank you,

Raul

[raulblack]

I did a little further checking. When I flip the work putting the top-side down in the Mega-Mold, the block angles are 90 degrees from the base of the Mega-Mold.

AngleCorrectWithTopDown.jpg (48.74 KiB) Viewed 5769 times

But I now have a 1/32" to 1/16" gap between the neck block and the Mega-Mold.

TopDownNeckBlockHasGap.jpg (50.52 KiB) Viewed 5769 times

It appears to me, everything was fine until I flipped the work and trued the top. The Mega-Mold appears to have forced the sides away from a 90 degree angle when the sides are lifted up. The angle is correct when the work is removed from the Mega-Mold. However, you can see the top of the block is no longer true to the rim.

OutsideOfMoldAngleIsOK.jpg (53.12 KiB) Viewed 5769 times

I suspect I might have the posts of the Mega-Mold a little to tight to the sides of the guitar, thus forcing it out of shape a little when flipped. It's a snug fit. Has anybody else had problems with this.

[ken cierp]

First without seeming to chastise -- a warning to anyone building a KMG kit if you decide to remove material before the instructions tell you to do so, that action is will likely result in a problematic issue. Make no assumptions and please contact KMG first!

Was the rim assembled using this process?
http://www.kennethmichaelguitars.com/rim.html
Including the joint pinning operations?

More picture are necessary to enable analysis of this issue -- please place the rim top side down on a perfectly flat table or bench. Take some pictures of the table contact around the perimeter and at the neck and tail blocks.

[ken cierp]

Perhaps its the camera angle -- but it appears that the tail block has the contour toward the inside?

[Dave Bagwill]

"Has anybody else had problems with this?"

I've found over the course of a couple years now, that the MM and the instructions are not the cause of any mistakes I've made. Usually, I failed to ask a question before just storming ahead - just my nature, I guess - and then asked for help when it did not work; my bad. Ken is very very good at explaining and clarifying and, since we all have digital cameras now, he can diagnose problems and answer questions in no time. Once we've made a mistake, it might take a little more to time to correct it, but there are very few mistakes that cannot be rectified, and teach us something as well.

Just sayin' - you can trust the MM, it is a great piece of engineering.
I expect the rest of your experience is going to be real good!!

[raulblack]

Ken:

Thanks for your speedy reply.

I assembled the rim as closely to the instructions you linked as I could. Somehow, I got off on the next page at the section "Sand the top edge so everything is uniform."

Here are pictures of the top-side of the rim facing down on a flat bench. I used a light on the backside to exemplify any gaps between the mating surfaces. The rosewood rim is perfectly flat on each end where the blocks are. It has a slight gap between the waist area and the table on each side.

FrontNeckBlock.jpg (39.98 KiB) Viewed 5762 times

RightSide.jpg (50.48 KiB) Viewed 5762 times

BackTailBlock.jpg (45.75 KiB) Viewed 5762 times

LeftSide.jpg (49.08 KiB) Viewed 5762 times

[raulblack]

The angles of the neck and tail block is out just a bit when laying flat on the bench, but not as bad as the sanding error when flipped topside up in the Mega-Mold.

NeckBlockGap.jpg (45.87 KiB) Viewed 5762 times

TailBlockGap.jpg (44.1 KiB) Viewed 5762 times