Home made guitar cutter

[David J.]

David,

How is it going? Have you advanced any since your last post? Have you tried to cut the cutting board? Did it work? I'm really impressed with what you've shown us so far, and I'm waiting on the edge of my seat to see an update!!

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I did indeed get the board cut...

I first tried to mark 1/4" spacing on the board itself to guide the cutting, but once we got it on the tablesaw it became apparent that it wasn't going to work out well. My friend Don who is a pretty good woodworker played around with ideas and finally settled on using both the fence and the miter gauge. The fence has a measuring guide and was shifted 1/4" after each cut while the miter guage was used to push the board and ensure it remained square to the fence at all times.

It took quite a while to make all the necessary cuts (and several unnecessary ones that were discarded), but you can see the results are fantastic. There is only one finger that is a bit larger than its neighboor due to having to switch the fence to the opposite side to take advantage of the table extension. Others following in my footsteps can avoid that necessity by starting on the correct side.

I haven't finished the frame, but couldn't resist trying the board manually with a single piece of wire tied to two sticks for handles. I had to count every fourth slot so it took much longer than it will with the frame but it cut very nicely. That has energized me to get back to the frame.

Speaking of which...

I realized after making those carefull "L" shapes with the brazing rod that I didn't have to be so precise. It was so long since I had last read the instructions that I had forgotten that I was supposed to use a steel brush as I tinned. Above you can see where I reheated and brushed the surface. That is the end where I am going to braze on the round tube for the handle. Since the entire end is tinned I don't have to be concerned about where I want to place it. You can also see that where I had placed so much brazing material it actually ate into the aluminum bar so that there is a slight depression after it was brushed out. The good news here is that everyone else can forget about having to learn to be very accurate and neat when tinning the pieces. Just heat it up, slap it on, and brush it around.

So to sum up this post, the cutting base for the homemade guitar cutter is a simple piece of 1"x12"x12" plastic cutting board, available online and at many supply shops for a fairly low cost. That helps in the effort to keep the total cost in my initial range.

[David J.]

I would definitely get those corners cut at a 45 degree angle on a vertical band saw before welding them together. The joints will be stronger and much more attractive. You could also probably save some effort by simply picking up a heavy duty deep channel Neilsen aluminum frame from a picture framing shop and drilling it out.

I was going to do something similar only I intended to use actual guitar strings and machine heads for the business portion of the cutter. I'd be afraid that bolts would snap the wires prematurely.

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Could you describe the cuts you are thinking of? The two cross pieces are butt brazed to the sides of the stringers so I'm wondering where you are thinking of placing the angle.

I'm planning on using machine head bolts with holes drilled to tighten the wires just like commercial models. I had briefly considered buying actual guitar tuners but discarded the idea after calculating the cost of even the cheapest economy tuner.

The picture frame might work, but I'd be interested to see how much tension one of those could hold without buckling. Picture frames aren't designed with this sort of use in mind. I may have over engineered my design with 1/4" aluminum angle, but stringing up to twenty wires with a tension of only 10-20lbs each encouraged me to err on the side of strength.

[ChristopherMichael]

Does anyone here have a guitar? If so, can you post some close ups of the thing?

Edited March 13, 2007 by ChristopherMichael (log)

[nduran]

Could you describe the cuts you are thinking of?  The two cross pieces are butt brazed to the sides of the stringers so I'm wondering where you are thinking of placing the angle.

I was just thinking of a classic miter joint with some reinforcement, but it looks like you're only going to have wires running along one axis, so the butt joint might be better there.

I'm planning on using machine head bolts with holes drilled to tighten the wires just like commercial models.  I had briefly considered buying actual guitar tuners but discarded the idea after calculating the cost of even the cheapest economy tuner.

Yeah, they're not cheap. I just happen to have a couple sets laying around from scrapped guitars. I think the ball end strings would make setup a bit easier, but maybe not if you want to be able to adjust the spacing.

The picture frame might work, but I'd be interested to see how much tension one of those could hold without buckling.  Picture frames aren't designed with this sort of use in mind.

You'd be surprised. I used to frame pictures professionally and the wall mount almost always gives before the actual frame does, even when you've got some insanely heavy mirror or triple-glassed shadowbox display in there. The typical pre-cut Nielsen kit parts you'll find on the rack at the craft store probably would not be able to take it, but if you had one of their wider, deeper mouldings custom cut for you, I don't think there would be any buckling issues at the dimensions you're working with.

Edited March 13, 2007 by nduran (log)

[gap]

I did indeed get the board cut...

David, thanks for the update - I think several of us are following with interest.

I chatted with my brother-in-law just this weekend and showed him some pictures of a guitar cutter (he had never seen one before but is handy at building things). We're thinking of giving it a go after the dozen or so other projects on at the moment.

[Tweety69bird]

David,

I am so impressed by how nice your platform came out with all the 1/4" cuts. Everything is sooooo straight! Did you go over it with a brush to help remove the extra fibers from between the cuts? I don't know what a fence is, but I'm sure my construction-savvy better half will know what it is, and I'm sure he has a miter guage. I am so going to try to make one of these. Anyone I speak to that's not into pastry and try to explain what a guitar cutter is can not believe how expensive they are. I think they think I'm lying! I couldn't believe how much a sugar box was, so I made my own for a fraction of the cost. Thank you for sharing your experience with us!

[David J.]

Last weekend I made my first attempt to assemble the whole frame. I started by clamping the four sides to the wood form, then heated up one of the joints. The first thing I noticed was that the big gap I was worried about slowly shrunk as I heated the piece. In fact over the ten minutes it took to get it hot enough to melt the brazing material the short side (1 foot) expanded about 1/4". I worked both ends of the short side but had trouble filling the gap in the second joint. It just wouldn't stay filled over the full length of the joint.

Finally I left the piece to cool down and discovered the second problem. It contracts as it cools and trapped the wood form as it did so. In addition it must have weakend the joint because it broke free a couple days later.

I figured the problem was that even with MAPP gas the flame just wasn't hot enough to get the joint up to temperature without heating the entire piece. I would require an oxygen flame and that meant buying a welding kit. I was about ready to drop the project but I found an inexpensive oxygen/MAPP gas torch kit. It was only $10 more than a simple MAPP gas torch so I bit.

I tried that tonight. Unfortunately I found that even that flame won't heat the joint enough to melt the brazing rod without heating the entire piece up. I believe a big problem with my design is that the large pieces of aluminum are too good a heat sink and just drains the heat away from the joint. The brazing rod isn't quite as easy to use as the instructional video would have one believe. Perhaps that is just because I'm not an accomplished welder to begin with.

So once again I'm stuck. It's getting to the point where even if I do eventually complete a frame it may take more skill and equipment than my original design goal of being able to be built by any reasonably handy person with a few inexpensive tools. I am sorely tempted to take Kerry up on her discount and order a commercial cutter so I can get back to making chocolates.

[alanamoana]

sorry about all the roadblocks david j.!!

i'm extremely impressed with the progress that you have made, but it does seem that even as expensive as a commercial guitar can be it might end up being cheaper in the long run.

i wish i had a reason to buy one, because i'd do it in a second. they're great for cookie dough as well as ganaches and everything else. the labor and cut down on waste is incredible.

[Lloydchoc]

Wouldn't it be easier to take it down to a shop that can do TIG welding and have them weld it up in about a half an hour?

[David J.]

Wouldn't it be easier to take it down to a shop that can do TIG welding and have them weld it up in about a half an hour?

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What would be the cost of welding up four frames? For reference of how many joints ther are, my design is up at the top of this thread.

If we are talking about professional welding though, I would alter the design to use steel for lighter weight and less bulk. Probably square stainless steel tubing for the sides and some form of bar stock for the ends to hold the bolts.

[Lloydchoc]

Use the same design that you have. I had some aluminum frames TIG welded for $10 each. I went to a shop that was set up to weld aluminum frames so they didn't have to figure anything out.

[David J.]

Progress continues: I figured out how to braze the frame!

I used a pair of pipe clamps insulated from the metal by bits of wood so they wouldn't drain off heat from the work piece. I left out the center wood frame and just pressed the long sides into the short sections. That kept the expansion in check and prevented contraction from pulling the newly formed joints apart.

I used too much of the filler rods and made a bit of a mess the first time through, but the next time should be much neater.

I started with both the MAPP torch and the MAPP/Oxygen torches, but soon ran out of Oxygen in the latter and continued on with just the garden variety hardware store MAPP torch. I realized that the simple one is all you need. The trick is to wait long enough for the work piece to come up to temperature, and that can take several minutes. I suppose two regular torches would speed that up quite a bit but it isn't necessary.

Here's a closeup of one of the joints:

This particular frame is going to be a tight fit for the cutting board so I'm just going to make it my learning piece. Future frames will be cut 13" wide instead of 12" to give a good 1/2" clearance on either side of the cutting board. I'm also going to cut the pieces on the tablesaw to get perfectly square edges which will improve the look of the joints and ensure the whole frame squares up nicely.

The next task will be to drill and tap the holes for the bolts, drill the holes for the wires, and string it all up. That will be the proof of whether or not the design is strong enough.

[Kerry Beal]

That is a good looking joint. I think your cutter is going to be sucessful!

[David J.]

It's been a while as I have figured out how to get the holes drilled in the cap screws.

I first tried to drill by hand, but that was a dismal failure. I tried to use a center punch to get a dimple to start the bit in, but the bolts are stainless steel and refused to mark. Next I used a Dremel tool to grind a small flat on the bolt first and that sort of worked but not very well. I dulled a couple bits on the bolt before having to take a break and think.

I gave up momentarily and ordered bolts though Design Realization for $3.84 a piece, but ended up canceling my order when I found out shipping would be $24 if I wanted it in a week or $18 if I was willing to wait for three. That would have brought the cost to $62 for ten bolts and I just couldn't bring myself to double the cost of the cutting frame just for the bolts.

So it was back to research. I knew people drilled bolts for saftey wiring so I took that track. That was when I found this handy little jig:

Just what I was looking for...

I read that I needed a Cobalt drill bit to cut through Stainless Steel. This is supposed to be used with a 1/16" bit so I ordered the jig and went to the hardware store to pick up the bit.

My first attempt was to clamp the jig in a vice and hand hold the drill. That's how I snapped off two bits before giving up once again...

More time passed as I contemplated buying a drill press to cure my hand holding problem, but I just didn't want to add that expense to the project. Then I recalled a hand held drill jig/press I had that might do the trick. The problem was that it had to be pressed against a flat surface to work and the bolt jig was definately not.

Then I got the bright idea to clamp the jig between a couple boards cut for the purpose:

That gave me the flat surface!

So now I could drill.

I filled the tiny hole with as much oil as I could coax down and coated the bit with more oil before placing it and starting it up. The first bolt drilled through in about 20 seconds and I was elated. The next bolt I tried took a bit longer. I manged to break the tip of the bit off in another bolt. I think one bit is good for two or three bolts, but I didn't keep strict track of it all. Once you find the bit spinning without cutting don't just replace the bit and keep going. The heat work hardens the Stainless Steel and you will just end up ruining the next bit. I verified this so you don't have to. I hope to get three or four bolts per bit once I get the hang of how much pressure and what speed to run the drill at for optimum cutting. That would put the cost per bolt at $0.25 for the bolt itself plus $0.73 to $0.55 for the bit.

The finished bolt

I quickly strung a couple wires in the frame to test it out and that is when I discovered a design flaw.

No, the frame did not collapse under the strain. What happened was that I couldn't draw the wire as tight as I wanted. I turned the bolts and drew the wire into place, but once it was drawn tight enough to make the two 90 degree bends it wouldn't pull through any more. The bends work hardened the wire and it wouldn't flow past it. I should have realized that is what would happen, but Llyod had and example of it working so I didn't give it a great deal of thought. The wire will tighten fairly well that way, but just not as much as I would like. So now I'm looking for a half round rod I can use to greatly enlarge the radius of the 180 change in direction for the wire. I think a 1/2" diameter would do well. I haven't been able to find that for purchase anywhere so I might end up having to split a full round rod on the table saw.

[Kerry Beal]

Glad to see you are still at it and that it is going reasonably well. One neat thing is how much you are going to learn about metalwork doing this.

I bought a little tiny cheese cutter on e-bay a couple of weeks ago. Just waiting for it to show up. It has 2 sets of wires at 90 degrees to each other, with the wires spaced 7/8 inch apart. Should made a interesting teeny guitar.

Keep us posted.

[choux]

Hi David,

I've been reading with interest, and have been collecting materials. It was difficult to fing a thick cutting board, but I happened to run across one at my local housewares store. I have a question, what kind of blade did you use on the tablesaw to get a thin cut in the board?

My husband is in to RC(remote control cars), and suggests you look at 'rigging couplers' for RC airplanes. They are pre-drilled threaded shafts that may work for tensioning the wires.

Also, what kind of wire are you using?

[David J.]

Hi David,

I've been reading with interest, and have been collecting materials. It was difficult to fing a thick cutting board, but I happened to run across one at my local housewares store. I have a question, what kind of blade did you use on the tablesaw to get a thin cut in the board?

My husband is in to RC(remote control cars), and suggests you look at 'rigging couplers' for RC airplanes. They are pre-drilled threaded shafts that may work for tensioning the wires.

Also, what kind of wire are you using?

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Hi Choux,

I'm happy to hear that others are interested in my design. I've got ideas on how to make a easier jig/clamp for the initial brazing of the frame so stay tuned for that. Once I get done with the proof of concept I'm going to make another correcting for all the inaccuracies and problems I exposed with the first attempt. I'm also going to take more pictures including video to document the process.

I found the cutting board online for somewhere around $30 for a 12x18x1" board. You'll find lots of suppliers if you just Google "HDPE cutting board".

After searching the web for a couple days without success I found a "thin kerf" blade at Home Depot. I left the blade over at my friends home since it is his tablesaw I am using so I can't give you specifics right now. Basically it's got a 1/16" kerf and it's about 8" or 10" diameter. I'll try to remember to stop by the store again and see if I recognize it. If so I'll post the details.

I took a look at the rigging couplers and they look fine but for the fact that they don't have a socket in the top with which to tighten them. I believe they are meant to spin into a coupler freehand, then run a cable through the hole and crimp it in place. The guitar cutter needs something more like a tuning pin that can be turned under tension.

For the wire I bought 60lb test Stainless Steel trolling wire from alltackle.com. It comes in a 600' package which means I've got far more than I need. I'd be happy to send you some. There is no way that I'm going to use half of it.

The HTS-2000 aluminum brazing rods are another item that several people could probably split an order of. When I get my second frame brazed up I will measure how many rods I use so others can arrange a group buy. It shouldn't take but a fraction of the 1lb minumum order so people can split it and keep costs down.

The bolt jig for drilling is called "ALLEN SAF-T-BLOK STD" at aircraftspruce.com.

That's all I can think of for now.

David

[choux]

Thanks for the info David. We're thinking of using stainless steel tubing for the frame, it may help with your problem of the wires not bending. I'm only going to be making one frame, and 1" slots on the board since that's all I use now anyways. I have a friend who does welding so I'm going to get him to help. I'll post pics, I hope to get started soon.

[David J.]

I have a question, what kind of blade did you use on the tablesaw to get a thin cut in the board?

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Choux,

The sawblade I used is from "Ridgid" and is golden in color as it has a "Titanium Coating"and also has "LASER CUT-REDUCED VIBRATION TECHNOLOGY" (basically curling slots cut in the blade).

The blade is 7 1/4" in diameter with 24 teeth and the kerf is a mere 0.059”. The item number is R0724R

Here's a link I found:

http://www.ridgid.com/Tools/Framing-Saw-Blades/index.htm

[panini]

I totally appologise if I'm repeating someone else. I just did not have the time to read everything w/ mom's day and all.

I have made my own with some great sucess. It does involve collecting old residential ice makers. Even the commercial will work. There are many cube size varieties. Check it out.

pan

Edited May 12, 2007 by panini (log)

[Kerry Beal]

I totally appologise if I'm repeating someone else. I just did not have the time to read everything w/ mom's day and all.

I have made my own with some great sucess. It does involve collecting old residential ice makers. Even the commercial will work. There are many cube size varieties. Check it out.

pan

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Have you got any pictures for us to see?

[David J.]

More progress to report:

I've drilled all the cap screws and strung the frame!

I wrapped one end of the wire through a small washer to hold it in place:

The other end went over a loose 1/2" rod, back through the frame, and around the screw:

I didn't have a chance to try to cut the rod in half and found that it works just fine as it is. I was afraid that the combined tension of the wires might bend the frame a bit, but I don't have any evidence of that at all. I installed the wires from the outside in and non of them loosened as the others were put in. That shows the frame could be widened out to 15" or 16" without having to get thicker angle aluminum.

Nuts secure the cap-screws in place to keep them from backing out:

Finally here is a shot of the frame with the cutting board:

I bought some JB weld glue to attach the handle with, then I've got to create the hinge and base to mount the cutting table on.

[gap]

Way to go David - all that hard work is starting to take shape!!

[Kerry Beal]

Looking good!!!

[Chris Amirault]

Any updates?