Chapman ML7S Mod / Retopping and new body shape etc.

[JouniK]

Hi,

have had my Chapman Guitars ML7S for good 8 years now and wanted to do some changes to it.

Well it all started with a need to have some fret work done because 14 and 15th frets were buzzing across all the strings. Checked that those were popping out a bit. Guitar has stainless steel frets so I need to take it someone who has proper tools to do the work. That got me thinking that I could do some other things as well since the guitar has other issues as well.

1. Nut replacement. White nut has changed colour and wanted to change it to a black Graph tech one.
2. Bridge repositioning. I have had some weird buzz on the low B (7th string) at the saddle when I try to intonate it properly. Especially if I change tuning to drop A. I need to move the saddle all the way at the end over the string through hole and that probably causes some unproper tension/misalignment of the string to the saddle. I am trying to move the saddle a few millimeters further away and drill new stringthrough holes. There is about 5mm headroom still to have the high E string to intonate. Not sure why bridges are always placed so close to the neck so that saddles need to be pulled back so far that to have the strings intonate properly even at standard E tuning. Well probably so if someone uses other that 9s or 10s at the high E.
3. Going to change the pickups to Fishman Moderns.

After my first build with poplar burl top I had been thinking if I can have the same wood as a top on this guitar as well. I wasn't so interested on the color and body shape any more as well.

So that led me to this project. So I am retopping, changing the body shape a bit, bridge repositioning and nut replacement. It is going to be scary but interesting project since I have not found from the internets that anyone has done something like this before. Plus I am doing this at a elementary school woodwork class room and equipment. Not saying it is bad at all but resources are a bit narrow and not so top notch.

This was the color and body shape when I bought it. I has a full mahogany body, set neck (this brings a bit more challenge to this) and string through construction.

A few years back I sanded the finish down and changed the color of it.

So I am starting out with cutting the both "wings" off and routing out 6mm from the top of the body to make room for the new drop top. Yeah didn't want to do a thin veneer top since getting of the finish sanding would take ages, I do not have tools to glue the veneer so good that it would last and I also wanted to have some curve on the top. So I ended up buying 2-piece 7mm poplar burl wood for the top. I did not find any good sources of mahogany for the wings so I bought some Red Willow blanks. This would not matter so much because I was thinking of not have the back and sides as natural finish anymore so going to paint as gloss black.

Wish me luck!

Edited October 26, 2023 by JouniK

[Bizman62]

38 minutes ago, JouniK said:

Wish me luck!

Luck wished! That's going to be an interesting project to follow, chewed fingernails and white knuckles... Then again it's not much different to building a radiused top neck through.

50 minutes ago, JouniK said:

Checked that those were popping out a bit. Guitar has stainless steel frets so I need to take it someone who has proper tools to do the work.

"Popping out"  - does that mean that they've jumped out of their slots? You can test for a gap by sliding a post-it note under the fret. If there's a gap, a brass/nylon hammer might do the trick. If that doesn't do it, wicking some super glue under the fret and clamping with a radiused piece of wood will push it down. 

Of course it can be something else, like a minor hump at the end of the potentionally too short truss rod. Leveling and recrowning the problem frets should fix that.

Regarding proper tools, one of the best tools is a strip of wet'n'dry sandpaper attached on a length of aluminium profile - or a bubble level. And a crowning file can be made by filing a groove to a piece of hardwood and attaching a strip of wet'n'dry into it. For just two frets getting fancy diamond files is overkill.

[JouniK]

54 minutes ago, Bizman62 said:

"Popping out"  - does that mean that they've jumped out of their slots? You can test for a gap by sliding a post-it note under the fret. If there's a gap, a brass/nylon hammer might do the trick. If that doesn't do it, wicking some super glue under the fret and clamping with a radiused piece of wood will push it down. 

Of course it can be something else, like a minor hump at the end of the potentionally too short truss rod. Leveling and recrowning the problem frets should fix that.

Regarding proper tools, one of the best tools is a strip of wet'n'dry sandpaper attached on a length of aluminium profile - or a bubble level. And a crowning file can be made by filing a groove to a piece of hardwood and attaching a strip of wet'n'dry into it. For just two frets getting fancy diamond files is overkill.

I cannot see that there is a gap or they are popping out or not but I tested with kind of a fret rocking tool that those 2 frets seem not to be level with the other ones around. I might try those methods once I get this project to that point.

[henrim]

When I read about fret buzzing with drop-A tuning I had a 6-string in my mind . Was relieved to find out it is actually a 7-string.

2 hours ago, JouniK said:

Plus I am doing this at a elementary school woodwork class room and equipment.

Don't know how the workshops are equipped today but back in the 80's we had pretty good tools. I'd assume far better than most builders have at home. Obviously there are no guitar specific tools but then, most specific tools are made/can be made in the workshop.

[JouniK]

2 hours ago, henrim said:

When I read about fret buzzing with drop-A tuning I had a 6-string in my mind . Was relieved to find out it is actually a 7-string.

Yeah. It has a 26,5" scale lenght.

 

2 hours ago, henrim said:

Don't know how the workshops are equipped today but back in the 80's we had pretty good tools. I'd assume far better than most builders have at home. Obviously there are no guitar specific tools but then, most specific tools are made/can be made in the workshop.

Not bad at all. This school has definitely better than what I remember from the 90's of a another small town school. Good bandsaw, tablesaw, joiner+planer, hand router and random orbital sander,..and a teacher/supervisor with me to talk with problems with these machines. Everything what I need other than I need to probably buy myself a router bit (I do not personally own a router) just for making new pickup and control cavities since the selection there is very limited. And there are a few people using the same stuff all the time so a bit waiting as well. It is kind of a "folk high school" thing, "Kansalaisopisto" in finnish.

[henrim]

32 minutes ago, JouniK said:

probably buy myself a router bit

Yes, they propably don’t have a template bit with a top bearing. Which is quite likely what you want for the job. Although, you may want to have two bits. A short one for the pickup cavities and a long one for the control cavity. Of course you can do everything with just one long bit if you set up the pickup templates higher from the surface. Or forget the router and drill the corners with a forstner bit and chisel the rest. I have multiple routers and all the bits but I'm happy if I don't have to use router at all  Of course a router is invaluable if you have to do multiple pockets a day.

[JouniK]

1 hour ago, henrim said:

Yes, they propably don’t have a template bit with a top bearing. Which is quite likely what you want for the job.

They don't. That was my first question when the course started. Yeah. doing it with a router+bit with a top bearing and using a template will make cleaner result and faster. I think. Me trying to do those cavities with a chisel would end horribly...probably.

[Bizman62]

4 hours ago, JouniK said:

It is kind of a "folk high school" thing, "Kansalaisopisto" in finnish.

That's what my workshop is as well. Partially the space is shared with the town carpenters but they don't allow us to use all of their tools. Thankfully there's similar tools for us. And the quality and settings are partially 'meh'.

[JouniK]

Woods for this build

Cutting off the "wings/horns" whatever they are called. I cut the top horn with a bandsaw by hand finished the cut with a joiner. Used that as a support for cutting the bottom horn with a bandsaw as well. Was not able use the joiner for the second cut because the headstock is tilted and other dimension limitations.

Finished the that join with a piece of planed scrap wood blank and sandpaper. I got them decent enough to be glued.

Next thing was to figure out how can I get 6mm off from the top of the body. Ended up using a hand router and made up router sled from a scrap laminated kitchen cabinet wood found at the workshop. Attached body to the "router sled" with a tape and ca glue. Stuck so good that I had difficulties to get the guitar off.

Since I did not have router bit with a guiding bearing I left about 1-2mm away from the neck just be on a safe side and removed the rest with a chisel. Body needs a bit sanding before glueing the new wood on top. I think I succeeded fairly well. Body is exactly the same thickness all across the blank.

 

[ADFinlayson]

He's made a Chapman stick 

[JouniK]

Planing the "wings" to the same thickness as the body...or what is left of it and then glueing pieces together..

[Andyjr1515]

Nice seeing the concept start to take shape.  I like that top wood very much

 

[JouniK]

Drawing and testing out the body shape to the top blank. Sawing the neck pocket and fitting the top to the body/neck. Project coming together slowly but surely. Doing this stuff on an apartment floor since other things taking all the time at the workshop the rest of the year...wife inventing stuff for me to do and fix. 

[Bizman62]

42 minutes ago, JouniK said:

wife inventing stuff for me to do and fix

I hear ya! I'll be at retiring age in a few years and due to the changes in the retiring age my four years younger wife can retire only after seven years. Seven years! What do you think I'd have to do home alone during those years??? Hell no! I'll continue working part time during that so we can share the household chores more evenly!

After that rant I must say the top looks fantastic and the fitting around the neck tight as - hmmm... for some reason I started thinking of my early adulthood. But 'glove' was the word I meant.

[JouniK]

New year, new progress. Body shape and headstock rough cut with bandsaw. I will be adding a poplar burl top to the headstock as well. Next sanding the body sides, routing control cavity to get a estimate on how the guitar will balance itself in playing positions with hardware on it.

[JouniK]

Hello! A month has passed and slow progress since other little projects came along like enlarging our bed frame to accommodate larger futon.

I went ahead and also booked myself to another folk high school "course" where I can work 7 hours straight (compared previously 2h/week) with better tools and facilities just to get this project finished some time in the future.

Got some templates done using some scrap wood and the control and pickup cavities routed. Did those using 2 different routers but the same router bit (DeWalt and Festool). Liked the DeWalt one more. More stable and the controls were better.

Then filling the voids of the poplar burl. Used black wood filler with a glue gun. Picked up this method from Crimson Guitars youtube channel. Not sure what is so special about this glue (https://woodrepair.com/KNOT-FILLER/WR1) but I guess it is made for wood knot filling specifically. Probably is a little harder than normal hot glues and sanding it might be better. Not sure since I have not used these before. Not cheap stuff and I only found one retailer from Finland (or in Europe) where I could order these.

Then to the second best thing in guitar building after staining...shaping the body edges with files. These were just initial try outs. Time ran out today to get the whole body finished. Lets see what the final shape will look like.

 

Edited February 17 by JouniK

[Andyjr1515]

That's looking really good.  What a difference!