Home made guitar cutter

[David J.]

Like many folks here I would love a guitar cutter but don’t have a thousand dollars to lay out for one.

I have read the threads here and I’ve realized that there is a need for a design that can be built for under $300 by someone with little more than an electric drill, a hacksaw, and a propane torch. Lloydchoc made a great fixed width cutter but I would like to go a bit further and build a modular one that uses a hinged shearing action and can support different spaced wire frames. I have ideas for the construction technique, but I have questions about the design of the device itself that I hope you can help to answer. Feel free to answer whether or not you actually use a cutter right now.

1) How large a cutting surface do you need? Commercial models have 15x15” tables, but do you really need or use all of that? What size ganache casting frames do you use regularly? Obviously the smaller the wire frames are the easier it will be to build.

2) Would you prefer wires to trim a bit of the edge of the ganache sheet on each side, or would you rather have two less wires and let the edge of the sheet stay as it comes out of the frame? Given your choice, would you make casting frames just a tiny bit large so the edges get trimmed without a whole lot of waste?

3) How important is a backstop on the cutting table? I see models with and without.

4) What size wire spacings do you or would you use?

5) Is there anything important to you that I haven’t thought to ask?

[stscam]

David,

Ambitious project - good on ya mate. My comments are contained in your quote, prefaced with the >> symbols.

1) How large a cutting surface do you need?  Commercial models have 15x15” tables, but do you really need or use all of that?  What size ganache casting frames do you use regularly?  Obviously the smaller the wire frames are the easier it will be to build.

>>1/2 sheet size (13x18) would be very nice, I hate to say. Perhaps not for ganache, but for pates de fruits and marshmallows.

2) Would you prefer wires to trim a bit of the edge of the ganache sheet on each side, or would you rather have two less wires and let the edge of the sheet stay as it comes out of the frame?  Given your choice, would you make casting frames just a tiny bit large so the edges get trimmed without a whole lot of waste?

>>No preference.

3) How important is a backstop on the cutting table?  I see models with and without.

>>It's helpful for lining product up square. If you had some other way to do that (lines, scribed marks, whatever), that would be okay.

4) What size wire spacings do you or would you use?

>>We use the 30mm (1-1/4") 90% of the time.

5) Is there anything important to you that I haven’t thought to ask?

>>The ability to clean and sanitize are important considerations. A way to keep the wires tight and not have to do a lot of retensioning would be good.

←

Good luck & keep us posted.

Cheers,

Steve

[alanamoana]

1) How large a cutting surface do you need?  Commercial models have 15x15” tables, but do you really need or use all of that?  What size ganache casting frames do you use regularly?  Obviously the smaller the wire frames are the easier it will be to build.

if it would be for a small shop or home use, i like 10"x10"...i got an acrylic frame custom made and it is great because you can cut 100 pieces...easy for counting production

but, i agree that half sheet size (in the length direction) is good. otherwise it increases work because you have to cut off part of the dough, pate or whatever and cut down two non standard chunks of stuff.

2) Would you prefer wires to trim a bit of the edge of the ganache sheet on each side, or would you rather have two less wires and let the edge of the sheet stay as it comes out of the frame?  Given your choice, would you make casting frames just a tiny bit large so the edges get trimmed without a whole lot of waste?

i don't think the wire placement is a problem. if based on the above answer, you'd just need the nine wires to cut ten rows. but it depends if you're making exchangeable width frames. extra wires isn't a problem.

3) How important is a backstop on the cutting table?  I see models with and without.

i think it is important because the stuff moves on the platform. you need it to keep everything aligned. particularly with firmer items like ganache and cookie dough.

4) What size wire spacings do you or would you use?

i like 1/5 inch, 3/4 inch, 1 inch and 1-1/4 inch

5) Is there anything important to you that I haven’t thought to ask?

←

can't think of anything right now, but i'm sure i will later. let's see what you come up with?!

[etalanian]

Great project!

I would like to see one that is adjustable, halfsheet size, easy to clean, with a backstop.

But I think rectangles aren't going to be easy, and may not even be possible, because the product has to be turned 90 degrees to make the second cut. It would have to be a little larger than 18-inches square to be able to do that. Quarter sheet size may be more practical; halfsheets could be cut in half first. So it could be a 13-inch square.

Hope you are successful. Please keep us posted.

Eileen

Edited June 27, 2006 by etalanian (log)

[David J.]

Thanks for the feedback and encouragement.

I see that the preferences are shaping up to a half sheet and quarter sheet cutter. Is there really a call for a home built half sheet cutter? I'm wondering if there are any businesses large enough to need one that don't have the funds to purchase commercial.

Eileen is right in her observation that the table has to be square and a little larger than the product to keep it from falling off. That would dictate either 19" or 13" square.

Now that I've heard your preferences I will detail my construction ideas:

1) I am considering aluminum angle for the base and wire frame. Lloydchoc showed that it is capable of withstanding the stress of the multiple wires. I also have the option of multiple size tubes and flat stock from the website OnlineMetals. The prices per foot are quite reasonable and range from $4 for a foot of 1.5x1.5x0.25" angle to $10 a foot for 2x0.375" bar stock. That would put the price of a frame in a decent ballpark. Unfortunately I am not an engineer and don't have the books to calculate how much stress each type of stock can take so it might take a bit of trial and error or gross over engineering. Does anyone know how much tension each wire is tuned to? I'm guessing 10lbs, but I could be way off.

2) I would use aluminum brazing rod to put it together. It is both much cheaper and easier to use than welding equipment. Anyone capable of soldering should be able to pick up the technique quickly, and it can be done with a propane or map gas torch available at your local hardware store. The finished joint is stronger than the parent metal, so it is just as good as welding for strength.

3) The table itself would be a PE cutting board with ¼ or ½" deep grooves cut every ¼ inch. It would sit inside the aluminum angle base to keep it from shifting and would lift out for easy cleaning or transport of the cut product to the dipping station. I found an online source for custom sized boards up to 1" thick, but you folks probably know the best source.

4) The cutting frame and base would be hinged together by simply drilling through both and brazing on a nut to the inside of the base. A knob with a threaded shaft and bushing would secure each side and allow quick and easy replacement of frames. The base might need feet to raise it up and those could be more angle aluminum.

5) I would like to investigate using inexpensive guitar tuners to tension the wires. I found an online source of economy tuners that are about $2 each. It's a called a guitar cutter, so why not? They are about 1" wide though, so I would either have to loop the wire back and forth to use one tuner for 2-4 runs or stagger them, perhaps in the front and back of the frame for the closer spacings. I favor using fewer tuners and looping the wire but I don't know if the friction would interfere with getting equal tension on each run. If I did that I would probably use half round stock to prevent sharp bends in the wire. Using the guitar tuners would prevent the need to drill a bunch of bolts and should make tensioning a snap.

http://www.stewmac.com/shop/Tuners/Guitar,...cs.html#details

Your thoughts?

David

[mrose]

David

There was a thread that showed a picture of a home made guitar, I can't find the name. Maybe some else remembers where it is.

Just found it Guitar Cutter

Mark

Edited June 27, 2006 by mrose (log)

[David J.]

David

There was a thread that showed a picture of a home made guitar, I can't find the name. Maybe some else remembers where it is. 

Just found it Guitar Cutter

Mark

←

That's Lloydchoc's cutter that I was referring to. I'm starting from there and furthering the design to be hinged with interchangable frames so it is easier to use.

[alanamoana]

5) I would like to investigate using inexpensive guitar tuners to tension the wires.  I found an online source of economy tuners that are about $2 each.  It's a called a guitar cutter, so why not?  They are about 1" wide though, so I would either have to loop the wire back and forth to use one tuner for 2-4 runs or stagger them, perhaps in the front and back of the frame for the closer spacings.  I favor using fewer tuners and looping the wire but I don't know if the friction would interfere with getting equal tension on each run.  If I did that I would probably use half round stock to prevent sharp bends in the wire.  Using the guitar tuners would prevent the need to drill a bunch of bolts and should make tensioning a snap.

http://www.stewmac.com/shop/Tuners/Guitar,...cs.html#details

Your thoughts?

David

←

i don't know anything about welding, etc. but i do think that looping the wire is not the best idea. uneven tightening as you mentioned is the first disadvantage. also, when one section snaps, the entire thing is useless and you need a really long piece of wire to replace the whole thing. when one snaps on a regular guitar, you just cut off a piece of wire and tighten it in. much easier.

the different sized cutting frames insert into a notched piece of metal on the commercial guitars. that way, you just pop them out. that makes up the hinge. no screwing or unscrewing a bolt to remove the cutting frames. not sure how to describe this better, but they are easy to use and effective.

[Trishiad]

When talking with a metalworking friend, he mentioned that the grooves in the platform would need to be quite small or the wires would be able to move a bit as they were reaching the bottom of the ganache, thereby causing an uneven slice.

He suggested using a metal base and having it cut with some special jet of water or something (my chocolate filled brain didn't quite understand what kind of tool he was referring to).

[David J.]

When talking with a metalworking friend, he mentioned that the grooves in the platform would need to be quite small or the wires would be able to move a bit as they were reaching the bottom of the ganache, thereby causing an uneven slice.

He suggested using a metal base and having it cut with some special jet of water or something (my chocolate filled brain didn't quite understand what kind of tool he was referring to).

←

I don't believe that the table slots in commercial cutters are what keep the wires from wandering. It would be the tension on the wires combined with the frame being attached to the table via a hinge with no slop. I think some form of bridge with thin slots would keep the wires from wandering on the frame, and a solid hinge should keep the frame from shifting relative to the table. At least that is what I am aiming for.

Does anyone have knowledge of the precise tension applied to the wires? That is one critical piece of information I currently lack.

[Lloydchoc]

When talking with a metalworking friend, he mentioned that the grooves in the platform would need to be quite small or the wires would be able to move a bit as they were reaching the bottom of the ganache, thereby causing an uneven slice.

He suggested using a metal base and having it cut with some special jet of water or something (my chocolate filled brain didn't quite understand what kind of tool he was referring to).

←

I don't believe that the table slots in commercial cutters are what keep the wires from wandering. It would be the tension on the wires combined with the frame being attached to the table via a hinge with no slop. I think some form of bridge with thin slots would keep the wires from wandering on the frame, and a solid hinge should keep the frame from shifting relative to the table. At least that is what I am aiming for.

Does anyone have knowledge of the precise tension applied to the wires? That is one critical piece of information I currently lack.

←

I found a 1" thick High Density Polyethelene cutting board at a restuarant supply house and I cut 3/4" deep slots in it with a thin kerf saw blade on a table saw. You need deep slots because the strings flex and by the time the center of the slab is cut through, the wire on the edge is 1/4" below the top of the cutting board. I make ganache slabe about 7x10 and I can cut 77 centers in less than a minute with a single action by having the wires go in both directions. I can generally get very accurate sizes without any "wandering".

As far a tension goes, tighten the wire until just before it breaks, or you could pluck it like a guitar string and tune it until you get the proper musical note.

[David J.]

As far a tension goes, tighten the wire until just before it breaks, or you could pluck it like a guitar string and tune it until you get the proper musical note.

Would you run a test on the tensile strength of the wire you use? If you hung a bucket from a length of wire and filled it with weights we could get an accurate measure of the breaking point you mentioned.

This is a big deal because I want to design an 18" frame that won't buckle under the combined tension of 38 wires (1/2" spacing). It makes a difference if the tension is 5 lbs (190 lbs total) or 15 lbs (570 lbs.). I'm trying to get a formula for the strength of varioius bar and angle stock so I can calculate the required dimensions, but I haven't gotten an answer yet.

I found a source of the aluminum angle you used for your cutter, and I can also get various sizes of bar stock if I need something stronger. Based on your experience, would you say that the stock you used would support 38 wires running in one direction across 18"? If not, would you say that aluminum bar stock 0.375" by 1.5" would do the trick?

[David J.]

I've been busy with other projects, but now it is time to push forward with my home-made guitar cutter. I've read enough recent posts to realize that several people are interested in a low cost model.

I have started with Lloydchoc's basic design using an aluminum angle frame and bolts for tightening the wires. What I have done is to extend the sides both front and back to allow the addition of a hinge rod and a handle. The hinge posts on the base will be just inside the cutting frame and have a slot cut meet a hole. The hinge rod will have flats filed so that it can slip inside the slot when the frame is vertical. This will allow a frame to be inserted and tilted down to lock it in place, then removed by simply raising it and lifting it out in one motion.

I am going to use structural aluminum angle which has a radius on each inside corner rather than the sharp angles of the more decorative angle that Lloydchoc used. This has over twice the strength so it should scale up to a half sheet sized cutter.

I have left dimensions of my drawings because it can be built in a range of sizes to fit what the builder needs. I am going to build the prototype with a 12" square cutting base as that is all I need and I want to keep the size down so it fits on my table with everything else.

Here are my intial drawings for comment before I order the material:

[Kerry Beal]

Looks like it will be fabulous. Keep us posted.

[gap]

David J,

how have you gone with your project. Any updates on designs or particulars for those of us looking at building our own guitar cutters?

Gareth

[David J.]

David J,

how have you gone with your project. Any updates on designs or particulars for those of us looking at building our own guitar cutters?

Gareth

←

Hi Gareth,

I've had the metal sitting in the basement waiting to be cut and brazed together for a while now. Other projects have gotten in the way, but since I just got two 6kg Mol D'art chocolate melters I need to resurect the project. I'll start cutting tonight and post pictures as I go. It helped that I was able to get some experience using a guitar cutter a couple months ago at the Advanced Chocolate Class with JPW.

David

[gap]

David,

I would really appreciate your thoughts as you go and any updated technical info, designs etc that you want to share. My brother-in-law is very handy at building things but has never seen a guitar cutter in his life. I'm in the process of finding pictures, diagrams and the like and then we are going to sit down and see if he can build it.

Gareth

[David J.]

Here are the basic raw materials for the cutting frame. Two four foot lengths of 1 1/2" alluminum angle, a 1/2" solid rod, and a one foot 1" OD tube for the handle.

I cut two 1' and two 2' lengths of angle using a manual mitre box and a hacksaw. The first tip is that you might want to just order the angle cut to length if you don't have a metal cutting bandsaw. It wasn't a lot of effort, but even with the mitre box the cuts were not perfectly square. That doesn't matter for the smaller pieces as the brazing material will fill in any gaps, but the ends of the long pieces might look better. It's not critical for operation though, and you can save a few bucks by buying longer pieces as I did.

I had decided to use a block of wood as a jig to ensure the pieces were all square and that if I built a second frame for different spacing wires they would all be identical. Unfortunately the board a friend cut for me isn't perfectly square so I need to find another one. If you can think of a better way to build the jig let me know. It needs to keep everything square and be repeatable. Additionally the corners need to be free because I'm going to be using a torch to braze the two short pieces in and any wood too close is likely to catch fire. The internal opening is 12"x13".

[gap]

Hi David,

no better ideas for a jig, I would have gone with the same method. Out of interest, what type of wire are you using for the cutters? Previous posts I have read said piano wire - is that what you'll be using?

Gareth

Edited January 22, 2007 by gap (log)

[David J.]

Hi David,

no better ideas for a jig, I would have gone with the same method. Out of interest, what type of wire are you using for the cutters? Previous posts I have read said piano wire - is that what you'll be using?

Gareth

←

I'm using 60lb test Stainless Steel Trolling wire. I couldn't find it local so I ordered it online: http://www.alltackle.com/american_fishing_wire.htm It comes in a boxed double spool of 300ft which is more than I will need for several cutting frames.

[ejw50]

Looks sweet, please keep up posted!

[David J.]

I'm waiting on my friend to cut me a new block for the brazing jig. Unfortunately for me he has been traveling for work and doesn't have a lot of time. I hope to get it next weekend so I can braze up the frame.

My current thought for the cutting table is to buy a 12x18x1" plastic cutting board and use a 1/16" kerf blade on the tablesaw to cut 3/4" slots every 1/4". I was trying to come up with a way to achieve a deeper slot, but they were all significantly more expensive than this. Given that at least one commercial cutter has only 3/4" depth I believe it should be enough. I'll be ordering the cutting board and looking for the thin kerf saw blade this week in the hope that I can get that cut at the same time I get the new jig.

[David J.]

Here's an update on progress so far:

I have a new wooden clamp jig with updated dimensions. I had it cut an inch and a half longer so I can clamp against the vertical side of the sorter pieces. I also had an 1/8th of an inch added to the width so I can be sure it will clear the sides of the 12 inch cutting board. That gives me a bit of room to fill with the brazing material, but we'll see how that goes.

This is how it will look clamped up for brazing. I cut the corners of the jig to allow access for the flame on the inside. I may add a couple more clamps.

The aluminum needs to be 'tinned' with the brazing material to start. That means that you have to heat it up enough to get the metal to melt the brazing rod all by itself without the flame. That opens the pores of the base metal and forms a proper bond with the filler metal.

I scribed an outline on the side pieces where the ends of the short pieces will join in, then dropped them in a vice and heated it up with a hand torch and a MAP gas cylinder. It took several minutes to get it hot enough due to the size of the piece and the fact that the conductivity ensured I had to get almost the whole piece up to temperature. However I did get the brazing rod to melt into the aluminum.

My first attempt was a bit sloppy

By the fourth one I was much neater.

The ends of the short sides need to be dealt with too

After I finished that much I realized that I'm going to have to drill the holes for the hinge rod and prep around them as well as the handle before I clamp it up for the final assembly. Once it is all together it will probably be too much metal to heat up with the torch for the initial braze. Fortunately once the aluminum is prepped the final joining only has to melt the brazing material together and that can be done in the flame.

It doesn't have to be pretty to function but after I get it all together I'll see how much I can clean it up with a Dremel tool. This is my first time working with the brazing material and I'm learning as I go. The second frame should go together faster and neater.

I cut a couple pieces of aluminum on a tablesaw with a carbide tipped blade and it went very smoothly. I would recommend that over a manual miter box. The cutting board is due to arrive today so I'll get that cut next weekend.

[Tweety69bird]

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!!

[nduran]

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.