My Kay Archtop conversion (just starting)

[Rob Powell]

So, inspired by my desire to have a mandocello, my inability to afford a decent one, comments by a few about converting a cheap archtop and my desire to do some luthier-type work....I purchased a couple of archtops on the bay for conversion. After doing a little research, I'm going to convert the burst but not the blonde. Here they are in all their splendor ;)

[Rob Powell]

The burst I believe to be a mid-60's Kay with a laminate body, solid spruce top and that wickedly retro semi-kelvinator headstock. The blonde however is from 1948-51 and is according to my research all solid woods (spruce top, maple body.) It was the bottom of the top of the line during those years and was not made after that. I haven't actually received either one yet but I'm thinking if the blonde is what I think it is, I'll just keep it as an archtop guitar.

So, I'm starting this thread to document the conversion process and to ask a few questions as I go along the way.

[Rob Powell]

So here are my first batch of questions....

1) What are the differences between mandolin and mandocello bridges? Are they compensated differently? Are the mandocello bridges just wider? Should I get a mandolin bridge or an archtop guitar bridge and modify it? Could I modify the existing bridge?

2) How about the tailpiece? Can I modify (or simply use in some way) the original tailpiece? Should I get a mandolin tailpiece for it?

3) Should I thin the neck down or does it need the mass for the extra tension?

4) If I do thin the neck what would be the optimal nut width? What would be the string spacing between the strings on a course? Is it possible to modify the existing nut or is that just a bad idea?

5) Do I use mandolin tuners or should I use guitar tuners or does it even matter?

In addition to the physical conversion, I'm planning to do a few other things.

I had thought I might put on a new radiused ebony fret board but I'm kinda digging the original mop "pick" inlays.

I most likely will refinish it as opposed to cleaning and touching up.

I'm toying with putting a veneer on the front and back of the headstock as it would help hide the peg conversion.

I originally thought I might even try to change out the binding with some wood binding but the checkerboard binding is growing on me ;)

Any thoughts and recommendations are welcome!

I'm especially interested in hearing from those who have done a similar conversion.

Thanks!

[Jake Wildwood]

Good going!

I'm tempted to do the same thing myself someday with an old archie.

1. Don't thin the neck... you'll need that thickness to counter the extra tension from mandocello strings.

2. To save yourself some trouble -- keep it as original as possible. Here's what I'd do:

a. Use the original tailpiece and just double up on two of the holes or slots (this works fine and was actually done on some old production 12 strings).

b. Think about switching to a mandolin/mandola bridge... they're adjusted properly for 5ths tuning.

c. As for the nut -- switch it out for a blank. You'll probably want spacing for each course like a mandola (a hair wider than a mandolin because the strings are thicker) and spacing between the courses like the guitar strings (a hair wider than mandolin spacing) simply to make the fingerboard more comfortable. Keep the original board, definitely!

d. Headstock veneer -- definitely a nice idea to cover up your mods. I always wanted to use some tortoise pickguard material to solve that problem. As for the tuners themselves... I always love old Klusons to keep the vintage vibe on old instruments... my plan would be to have 8 individual Klusons as opposed to mando tuners. I tend to think those really thick "C" course strings would work better with guitar-style tuners.

e. If you don't want to modify the instrument aside from nut and bridge, you can always just string the lower C and G courses singly, thus avoiding the whole headstock problem. I did this on an old Framus 3/4 a long time ago and it made a very nice octave mando with an interesting voice.

[Rob Powell]

Thanks Jake! It actually has old klusons on it which supposedly turn very easily. Some nice ideas there....

[Rob Powell]

Well, the blonde showed up yesterday and was not quite in as good a shape as I had anticipated and not quite constructed as my research indicated. It was indeed a solid spruce top but I'm now pretty certain that it's laminated back and sides with a nice veneer. It's had a neck reset and it wasn't done very well so it will have to be done again. The tuners are original but I fear the buttons are going to start crumbling any day. The tortoise binding is really nice except the heel cap is crumbling. Frets are ok overall but still needs a fret job and the dot inlays are just weird. They are definitely inlays but the material is suspect. Overall, pretty decent condition considering it's age (1949.)

So what does that have to do with this conversion? Well, I'm now thinking that either one is a candidate for mandocello conversion since I have to do work on both. My only regret would be the tortoise-oid inlay on the headstock which is almost enough to keep me from converting it. Maybe, I should just replace the neck and keep the original? The headstock is really the only collectible part of the guitar ;)

The other one arrives tomorrow....we shall see...

[Rob Powell]

The burst arrived yesterday and is in pretty good condition. I'm kinda diggin' it. That said, I took the strings off both of them and the nut was sticky taped in place on the blonde:))

So I'm cleaning them up, checking the frets etc to see what work needs to be done but unless something changes, I'm still converting the burst and fixing the blonde as an archtop guitar.

Might post my questions over in the builders section...

[Kerry Krishna]

Rob, ... I have done two of these conversions now and have another one on my bench right now. On one I shaved the sides of the neck down, and the other I did'nt , but had to eventually. The 6 string guitar spacing made the string sets so far apart as to make the instrument unplayable. And not just to me either! So that being said, I don't agree with Jake on that one thing. So for you, I would first have a really good think about everything before you start doing any work. Don't be impatient! I've done work right away on some of my own instruments that are brand new (to me anyway) without thinking about EVERYTHING, and end up with a wall ornament! If the blond does need a neck reset,then it is the instrument to use for this conversion. It's the perfect time to shave down the sides of the neck. As to neck width, the measurements from other instruments of this kind are all over the map. I measured one that had almost the same nut measurements as three on my mandolins! On the other hand,I have a bouzouki with a neck wide enough to put on another set of strings. So you have to do some measurements off of instruments that are available to you. Maybe one of the 'big boys' can speak to these measurements. Answers: 1; Bridge... For one of my conversions, I used an ebony mandola bridge . 2; Tailpeice...You could possibly modify the tailpiece you have with a GOOD drillpress or much better, do as Jake suggests (Good suggestion too!) and look for a replacement that was made for twelve string. They are in the ALLPARTS catalog. They look amost exactally like the one on your axe. Be aware you could just chose a mando tailpeice. The problems with that are that strings you buy very likely will not be long enough, and the extra string tension might blow the tailpeice up after a few years. 3; Neck... Lots of issues here! Be aware also if you decide to use the existing fingerboard, (this is what I would do!) the widest spaced fretboard dots will likely be sanded halfway through. If the asthetics of this do not bother you, then do it. The last conversion I did, I took some very close measurements and tranfered them. Since the neck was already off the instrument, and the frets were totally intact, I experimented! I left the frets on (!), tranfered the measurements, and took the neck over to my belt sander and went at it! I sanded the both sides of the neck and then rounded off the back into pretty much a u shape. That way it kept MOST of the wood. You NEED to keep as much wood as possible on the neck itself so that it does'nt start to self destruct. You CAN take the neck off with proper knowledge. Do as much reading as you can about all the aspects of what you don't quite understand.Frank Ford's 'FRETS' site would help maybe with that. I have done it three or four times without special tools. but the steam needle and a kettle sure helps! You will then of course have the fret ends that need to be dealt with though...4: Tuners... buy a set of half decent mando tuners. Do not cheap out on this! It would be another way to turn this instrument into a wall hanger. As to the rest:... Do a thin veneer on the front for sure, and one on the back too, but only if it makes a difference to YOUR asthetics. The only people who will look for a back plate veneer will be people who KNOW that it is a conversion and might want to be picky.. If that does'nt matter to you then... So thin is good! Make sure your machine heads are STILL gonna work! If veneer is too thick, you MAY have problems with them not fitting! (measure once, cut twice!) DO NOT refinish this axe! It would turn this project from 'do-able with a few problems' to " A Project Of Biblical Proportions". Remember K.I.S.S...Keep It Simple Stupid! Also It is a major job to replace the binding! So same applies for that!...Feel free to private message me if you need more specific advice and I can also be available for a phone call instead if that works better for you...... So here went an hour of my life. I hope this helps buddy!...Kerry Krishna in WAY North Canada...

[Rob Powell]

Thanks for all the info Kerry!

They BOTH need a neck reset and they BOTH need a fret job...so I'm sticking with the burst. I ordered the Stewmac needle to attach to my cappucino machine so hopefully I'll get the necks off this week.

I've gotta run now but thanks again....I'll post a little more of my intentions later.

[jim simpson]

what a great ambitious project. I was given a steam shark and wondered if it could be modified for a neck removal project. I have an Old Kraftsman archtop that has a loose neck joint. I need to re-set/re-glue it.

[jim simpson]

Here's a shot of the steam device:

[Rob Powell]

what a great ambitious project. I was given a steam shark and wondered if it could be modified for a neck removal project. I have an Old Kraftsman archtop that has a loose neck joint. I need to re-set/re-glue it.

I'm betting yes....I was actually thinking of getting a Steam Shark Jr. as opposed to using my cappucino machine especially since it appears to have gone missing or is still packed away somewhere (we moved here in July of 2007 but there are still unpacked boxes LOL)

Stewmac makes a steam needle/hose fitting that is basically what Frank Ford uses and may even be based upon his idea. Here's a pic of the Stewmac needle kit.

[Rob Powell]

Ok...here's some more info on what I have gathered. I'm doing this mostly as documentation on my own conversion but also as a document for others who might want to go down that road. I'm sure I have a lot more "don't do this" than "this worked really well" ;)

First, some info on the guitars:

The burst is what I believe to be a Kay K6840. I've matched up the fretboard inlay, the headstock logo and the woods to an early to mid-60's model. It's possible it's an earlier K6838 but unlikely. It doesn't have a model number or serial stamped inside (that I can find yet) but has N-11 and P3 stamped inside one of the F holes. Curiously or perhaps just coincidence, it's stamped inside the opposite F hole from the blonde.

The blonde is a model K42 and the serial number indicates it was made in 1949. The headstock and inlays are consistent with that. Research says that these models were only made between the years of 48-51. Apparently some were made all solid woods but this one is laminate sides and back. The back is a very nice single piece curly maple veneer. It's a beaut!

Now for the issues. As mentioned, the K42 had a bad neck reset and needs another as the heel is lifting pretty good. The tortoise heel cap is crumbling. It has some scratches and a few of them are relatively deep and should be repaired in some way before they become cracks. The neck is pretty straight and the fretboard is pretty level but the frets are varying heights and won't take another leveling. No truss rod that I'm able to see.

The K6840 is missing the nut from the truss rod and has a pretty fair bow in the neck as well as a slight lift at the heel. I'm pretty sure the neck has been reset and the heel was glued I believe to prevent further lifting. Neither instrument seems to have the original fretboard extension and the one on the K42 doesn't even match the neck wood. The bridge on the K6840 had been moved back over 1.5 inches which I think was an effort to compensate for the neck bow and intonation. Cosmetically, it's in pretty decent shape with only some chips and a few scratches. Again, the frets are varying heights and looks to have had a bad fret dressing (lots of chatter marks on the top of the frets.)

I have no misconception about either one of these instruments being a high dollar collectible but they do still have some collectible value and I'll do as much to them as necessary to restore them and perhaps make them a little nicer than they were.

Next post...the details on the stats and thoughts on the conversion.

Thanks to all and any who listen to my ramblings :grin: and also to any and all who offer advice!

[Rob Powell]

Ok... the K6840 is the real candidate for the mandocello for a few reasons but mostly because the neck is a little smaller, I believe it's a little less collectible and I paid less for it :grin:

The neck is 1.652 at the nut and 2.09 where it meets the body at the 14th fret and has a 25 inch scale length. The K42 has a 25.5" scale, a 1.67 nut width and is also a little wider at the 14th fret.

Some stats on other mandocellos.

A Weber archtop guitar style mandocello has a 1.685 nut width and a 25" scale length.

The Eastman archtop guitar style has a 1.75 nut width and a 25" scale.

A Gibson K-1 had 1.625 nut and 24.75" scale.

A Gibson K-4 had 1.625 nut and 25" scale.

A Gibson K-5 nut was slightly smaller at 1.5625 and 25" scale.

Finally, both a Santa Cruz flat-top and a 1938 Epiphone archtop conversion have a 1.5" nut and 25" scale.

Considering the K6840 nut width is less than 1/32" wider than a Gibson K-1 or K-4 looks like I won't have to slim the neck after all. Happy camper ;)

I ordered a couple of nuts so all I have to do is figure out the string spacing. I think I downloaded a chart that will help with this. I'll post that info later.

As I mentioned, the truss rod nut is missing and the neck has a pretty good bow in it. Hopefully, the truss rod isn't broken :( On top of that, the heel is lifting. I'm going to get a nut for the truss rod and see if I can get some of the bow out that way. That might even help the heel lift and negate the need for a reset. I'll report back on that later today.

As I also mentioned, it needs a re-fret so I've ordered some pre-cut frets from guitarpartsresource and also some fret wire and fret tools from Stewmac as well as some nut making tools. Again, I'll post later what I ordered as I'm running out of time this morning. I'll also post here how the stuff I ordered worked out and a running total for the project.

Thanks for reading!

PS - can I say thank goodness for Frank Ford and Frets.com? What a great resource!

[Rob Powell]

Well, yesterday did not go as planned....I assumed the truss rod nut would be 1/4" and picked up 1/4" nuts and washers....looks like the truss rod nut is 3/16". Now, I must say that I didn't go unprepared....I did look for 3/16" nuts but didn't find any. I now think that I should have looked in the plumbing department...in any case, I'll get the nut later today and attempt to straighten the board.

As for what I have purchased....mostly for fret work at this point.

From Stewmac I got:

1 - #4371 Fret Press Inserts 12" radius
1 - #4479 Neck Support Caul
1 - #3770 Fret Rocker
1 - #4895 Fretting Hammer Hammer with plastic and brass faces
1 - #4059 Neck Joint Steamer Needle, hose and clamp
1 - #4465 Seam Separation Knife
1 - #4455 Dual-grit Diamond Fret File For medium fretwire
6 - #0152 Medium Fretwire Medium/higher, 2 ft
3 - #6011-V Vintage Bone Nuts Shaped nut for Gibson, 1-5/8"
1 - #4607 Bridge Heater and Fingerboard Iron

Which came to about $290 shipped.

This wasn't too bad when you consider that I needed some of this stuff to complete my Stewmac F5 kit and I need it all to do the conversion and do the neck work on the other archtop guitar.

On a side note, I found that I'm close enough to Stewmac that regular shipping is 2 days so no need to pay extra for 2 day shipping! Awesome.

On our favorite auction site I bought some (9) nut files and a puller/nipper all of which got really good reviews.

Add that to the total and it's around $360.

I didn't buy a leveler because I have sanding blocks and various grits already. I bought the radius insert with the intention of making my own caul for it and using it with a fret hammer as opposed to an arbor press. The bridge/fingerboard iron is for neck and fret removal. I probably could have made some of this or used/modified some "found" items but I'd rather spend the time I have doing the project, not making tools.

I also have a few tools I got originally for the F5 kit build...

I still need some tuning pegs and headstock veneer. I checked out the tailpiece and it will work pretty nicely (with loop ends no less) without any mods so I bought a couple sets of mandocello strings figuring I'd use one set for nut work and have a fresh set to string it up with when I'm done.

I'll post again when I have more to report...today it's searching for a truss rod nut, picking up some dowels for the peg head and since the Stewmac stuff should arrive today, hopefully attempting a neck removal if I can find the daggone cappucino machine.

I'll take some more pics before I start....

Again...thanks for allowing me a place to document this. I hope people will chime in if they see me heading down a prickly path ;) and I hope it helps someone else who might attempt this.

[Bernie Daniel]

Rob cool project!

My comments are:

1) good luck and thanks for posting all this -- very interesting.

2) I definately agree with Kris and to nut/neck width when he says:


The 6 string guitar spacing made the string sets so far apart as to make the instrument unplayable. And not just to me either! So that being said, I don't agree with Jake on that one thing.

I converted a 1960 to 70's era Arianna drednaught to a mandocello and the result sounds awesome --rolling thunder -- but that wide neck is torture -- I play on it sometimes just to make me appreciate my K1 more! :)

I posted some pics of the final result and can find a link if you are interested.

Your nut and scale length measurements agree with the ones on my K1 -- I would like to know what you end up doing on the bridge -- am in the process of making a new saddle for the K1 -- out of ebony. The idea of buying an archtop guitar bridge seems like a great one that I did not think of.

I queried them and both Weber and Siminoff will carve out a new mandocello bridge for reasonable amounts of money. I did not bother to contact Gibson as their approach is usually to have you send it to them to do.

Also I hope the neck resets on those guitars were not done with a non-meltable glues!:crying:

[Rob Powell]

Thanks Bernie...glad to know I'm not mostly talking to myself here ;)

I'm going to mark the new nut and put it temporarily in place before I make he final decision. I had done the approximation of scale length based upon the distance from the nut to the first fret. I remembered that the original bridge placement was marked on the top and put the bridge there and measured and wound up with 25.5 inches not 25 as originally thought. So either my original measurements/calculations were wrong or the place where the bridge was marked was wrong ...which wouldn't be unusual.

I guess I'll have to check the measurements again.

In any case, I'm rethinking the neck slimming as I'm now guessing that the real issue isn't at the nut but at the body. I'm betting that the Eastman and Weber both have less taper from the nut to the 12th.

It is interesting though that I'm going to putting 8 strings in the space of six, 2 of which are heavier gauge than on a guitar and yet, the neck needs to be slimmer....it's a puzzle.

I'm still in the mindset to refinish it so the neck may get a bit slimmer in the process anyway.

More later gotta run!

[Rob Powell]

Well, most of the tools arrived this week and so this morning I started on the real work.

I had already removed some of the frets which went pretty well with very minor chipping.

Yesterday I drilled a 1/16" pilot hole at the 15th fret for the Stewmac steam wand. I probed it with a wire string and found the pocket to be some where between the 14th and 15th but closer to the 15th. So, I starting drilling on a bit of angle and the bit broke inside the body :crying:

But wait! Turns out the Stewmac needle needs a 3/32" hole! The needle is actually 5/64" . I was assuming 1/16" only because of what I read on frets.com. So I drilled out the broken bit and still had to try a couple of angles to get into the pocket. I'm sure I chewed up something in the process:)) We'll see when I get the neck out.

I'm having trouble loosening the fingerboard extension from the body. I got Stewmac's bridge/fingerboard heater but it seems like it doesn't work as well for raised fingerboards. Either that or the glue is just plain stubborn. I'm pretty sure it's not hide glue and I'm also pretty sure it's not epoxy. Looks like it could be Titebond (or some other yellow glue) so I think I'll try a hair dryer on it later.

It could be that I'm just being cautious and not heating the iron hot enough...just not sure because it did loosen it some of the glue but not enough. Given that this guitar is from the 60's, if it is Titebond, it's Titebond orginal and possibly the steaming will help it.

I'm being as cautious as I can not because the instrument is worth a lot (it's not) but it wasn't $15 either. I think the fact that it wasn't 15 bucks is probably a good thing as it is one of the things that is making me be cautious and take my time. The other of course is that I want the outcome to be good:grin: not to mention my respect for almost any decent instrument. Yes, despite this being a Kay, it's actually a pretty decent instrument. The K6840 or it's predecessor the K6838, were near the top of the line with solid, carved spruce tops and pressed laminate maple bodies.

In any case, I'll be attempting the steaming and neck removal later this morning and I'll post how it goes :grin:

[Rob Powell]

So, first let me say that I am thoroughly underwhelmed by the Stewmac bridge/fingerboard heater. Perhaps it works really good on a flat top but it's for squat on an archtop.

All I really managed to do with it is discover that the pick shaped inlays are not mop but mots. Pics to follow.

Steam, however is a different matter ;-) The Stewmac needle and hose kit works great with a cheap espresso machine. The steam poured out of the neck and body (even out of the truss rod pocket) and worked it's magic on the fingerboard extension as well. It worked a little more than I wanted in a few places...pics to follow. I wish I had taken pictures of the rig and the steam coming out! Next time...

All in all, it was a good experience and I didn't ruin anything that wasn't fixable which was the primary goal along with learning. :grin:

[Rob Powell]

First there's a pic of the bow in the neck which was worse before I put the truss rod nut on and tightened a bit. It's even better now as I tightened it another 1/4 turn. One more slight turn and it should be gone. I'll put some relief back in it if it needs it after I string it up.

Also, a pic of the back pointing out one of the many chips in the finish. Also, you can see that the laminate has some nice figure.

Also, a pic of the headstock with the hardware and logo removed and the new truss rod nut. Turns out that logo is metal!

And lastly, a pic of the neck separation. It's not a very good pic but I think you can see where the problem is. As I may have mentioned, it had been apparently clamped and glued but the neck still pulled up.

[Rob Powell]

Here's 2 pics of the fingerboard...before and after I burned one of the mother of toilet seat inlays :disbelief: This also shows the oversized :grin: needle hole. I'm learning!

[Rob Powell]

Lastly, here are pics of the bocy and neck after the neck was removed. Two more problems here but nothing terrible. The top is coming away from the body at the neck block on one side from the steam. Also, some of the top came off with the neck at the fingerboard extension....all in all, I'm not in too bad shape.

Now, if I could only figure out what to do now that the neck is off :))

[Rob Powell]

Quick update on the calculations....measuring to the first fret from the nut, it looks like 25 3/8" scale which seems pretty common for an archtop.

I think whatever slimming happens on the neck will be a result of the refinish.

Today, I'm hopefully going to attempt to clean up and possibly reset the neck...I want to at least get it ready to reset.

I may also go to Woodcraft and get some veneer for the peghead and plug and drill it.

If I get to either of those, I'll be a happy camper ;-)

[Rob Powell]

Didn't get squat done yesterday BUT...I discovered what was causing the last oops...as it dried out from the steaming, I went back and looked and the side was no longer raised from the body. Hmmmm...then I discovered the reason for the neck issue.

The neck block is cracked on that side! Luckily for me, Frets.com addresses this in the neck reset on a 1946 epiphone. It had the same problem and even on the same side!

So, I've got another thing to deal with but it's all still good ;)

[dlp4]

Thank you for the posts...really cool stuff. I'm getting ready to do my first archtop resto so I am all eyes and...eyes. When you see a pro do it it looks easy. It's nice to see what really happens when I try it.

On the neck blanket, the Stew Mac only goes to 450deg F. It's 120V so no real need for the expensive controller they sell. I think just keeping an eye on it is ok. But you can buy this blanet at 1/2 price from the source :

http://www.omega.com/ppt/pptsc.asp?ref=SRFR_SRFG&Nav=heam01

Or, you can buy one with double the wattage so it will actually do something besides drain your wallet.


On the trussrod nut, I have used these from McMaster-Carr because they have a narrow profile:

http://www.mcmaster.com/param/asp/PSearch2.asp?reqTyp=parametric&act=psearch&FAM=threaded&FT_2044=133550&FT_6176=253464&FT_294=253371&FT_158=113399&FT_104=4054&session=desc=Allen Nuts;threaded,2044=133550,6176=253464,294=253371,1 58=113399,104=4054&desc=Allen Nuts&dscIDs=2390&sesnextrep=639817473001963&ScreenWidth=1280&McMMainWidth=1066

I see you already figured something out but I have an extra of the short ones with 10-32 thread (3/16" rod) I can send you if you like. They come in 10-24 and in different lengths. I just use washers under them to get the right depth or length.

When you get ready to refret I have an opinion worth considering: Pounding frets is a bad idea. It takes more force to overcome the initial friction when sliding two parts together and less to keep the part moving. Maybe you're an engineer and know this already. When you press you overcome the friction once and keep pushing until the fret is "set".

With the hamer method you have to overcome the initial friction everytime you beat on it and the fret is much more likely to enter the slot crooked and messed up and more likely you will embed the fret into the fretboard... just a thought. I've seen luthiers just cut a piece of hardwood with a radius and use a small drillpress for the arbor and do fine. Don't need to send $180 to Stew Mac unless you want to.

Keep posting!

[Rob Powell]

On the neck blanket, the Stew Mac only goes to 450deg F. It's 120V so no real need for the expensive controller they sell. I think just keeping an eye on it is ok. But you can buy this blanet at 1/2 price from the source :

http://www.omega.com/ppt/pptsc.asp?ref=SRFR_SRFG&Nav=heam01


When you get ready to refret I have an opinion worth considering: Pounding frets is a bad idea.....I've seen luthiers just cut a piece of hardwood with a radius and use a small drillpress for the arbor and do fine. Don't need to send $180 to Stew Mac unless you want to.

Keep posting!

Thanks! Good resources...and yeah, I came to the conclusion that pounding frets was bound to be fraught with peril in my case. That's why I bought the radius piece. I figured I could make my own caul using their brass insert and pick up an arbor press on the cheap.

Unfortunately, many things call and I haven't done much on the project recently although I'm going to be picking up steam heading into the holidays and some time off...

Post some of your stuff too...I'm thinking I may move this to a blog ;)