Official Luthiers Forum!

Hey Everyone,

Sorry if this is off topic here, but thought it would be the best place to ask. Can a person get good results with a carving duplicator such as sold here? Or is there a similarly price cnc type unit that would be a better investment? I am speaking of someone like me, who has zero experience with cnc, cad, etc.

Thank you.

Jeff

The prices seem --extremely high-- for what they are. You can get a K2CNC system for roughly the same price that'll give you better results, automated. I'm not sure about the probe systems offered by K2 but you can contact them about it. There are a few companies selling separate digitizing probes and they cost between $300 and 1K but they scan a piece once and you can duplicate it forever without having to rescan. And, if you take the time, you can move on to making parts using CAD which is even better.

A CNC will take a little more learning time on your part, but in this case using a duplicarver (at the same price as a CNC! Ludicrous!) would be like going to town on a pogo stick because you don't want to learn to ride a bike

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

[QUOTE=Bob Garrish]
A CNC will take a little more learning time on your part, but in this case using a duplicarver (at the same price as a CNC! Ludicrous!) would be like going to town on a pogo stick because you don't want to learn to ride a bike [/QUOTE]



Bob,

Thanks! I knew I would get some sound advice. I am looking at all aspects of being a luthier, from trying to make my own kerfing, to using a CNC. I want to be open to all of it, because I have not yet come accross any part of guitar building I have not enjoyed and learned from. Moving into the realm of CNC might be one of those things like carving braces, I never knew how much I would love it until I tried it!

Feel free to offer any suggestions, links, articles, etc. about any aspects of CNC, I would appreciate them.

Thanks again.

Jeff

I wrote this next message on another forum. It's long but it'll give you a good grounding in the important stuff. It should probably take awhile to understand it all so Google is your friend and think of it as a study guide.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

OK...this got long by the time I finished writing it...if you have any questions then ask away. I've spent the last 3-4 months heavily researching everything about CNC routers. And, since my day job is as a professional researcher I got a lot done :)

Step one is definitely learning Rhino. IMNSHO Rhino is still the best bang for your buck in a modeling program if you double the price. If you're a student or know a student or teacher then you can get Rhino for peanuts from ob.com on educational pricing.

After you're comfortable with Rhino (it takes awhile for most, do the tutorials and go through the level 1 and 2 training guides that come with it) you can check out the CAM software. Visual Mill/RhinoCAM are pretty good for less pricey stuff, but I'd go with MadCAM in that price range as it's impressed me most lately and it also has fantastic educational pricing. CAM software is easy once you can handle CAD software so you might just want to get it with your CNC.

It sounds like you're looking for a small, inexpensive machine to fiddle around with so the K2CNC ones are probably right up your alley. For a little more you can look at a Larken or Techno-Isel desktop with a lot more upgrade options (think of it as buying a house on a bigger lot)

Come to think of it, go to this link on the Techno website where they have a pretty comprehensive -free- book on the basics :

http://www.techno-isel.com/H840/H840cat.htm

They do spout a little hot air from time to time (ball screws aren't strictly superior to rack and pinion as they might have you believe, particularly the ones Techno uses) but it's 98% good stuff and it'll teach you a lot.

To really understand what you're doing with your own machine, I think it's important to see what the higher end ones have, also. It gives some perspective. There are different (loose) classes of CNC routers, from what I've seen, with different standard components and expected uses.

Hobby/Small business:
K2CNC
Shopbot
most of the kit systems

These use consumer (handheld) routers, usually stepper motors, bolt together frames or frames made mostly from extrusion (and sometimes MDF or ply).

Sub-industrial:
Techno-Isel
Larken
Precix

These sometimes use consumer routers, but usually use spindles. They have servo drives standard or as an option, and the frames are welded together. There's still some extrusion used but usually the frames themselves are solid metal. They can be upgraded with lots of craziness like automatic tool changers. These are the machines you shouldn't be as afraid of running full days.

Light industrial:
AXYZ
MultiCAM
CNT Automation

These are at least marketed as higher end than the sub-industrial ones, and you'll definitely pay for it. From what I've seen and heard the MultiCAM and AXYZ systems don't offer as much extra advantage as their costs would dictate, though. The CNT machines are -really- nice for the money...

These machines are generally really solidly welded steel and usually have brushless servo motors. They generally have thicker rails/guides and mostly don't offer anything less than a spindle. They also often have hand controllers or enclosed, pressurized controllers and are generally made to run in a production environment.

Above these you have things like Thermwoods, Andersens, Komos...the above all weigh less than 2500lbs whereas a Thermwood is a 7000+ lb monstrosity meant to work 16+ hour days.

Anyways, that's a lot of stuff but if you read all those companies' webpages and learn what all those terms I threw out mean, you'll be in pretty good shape to understand what you're looking at when you pick up a machine.

In general the differences in the machines relate to rigidity/accuracy (cutting precision and quality) and speed. For rigidity bolt together < welded extrusion < welded bar < heavy metal. For accuracy acme screws < bad rack and pinion < cast ballscrews < helical rack and pinion <= ground ball screws. Spindles have less runout than routers and are generally more powerful and thus cut faster, for longer, wear out much much much slower, and leave a better finish. Servo motors in general have more torque than stepper motors and move faster and more consistently. Servo systems are also 'closed loop' which means that the machine knows where it is and doesn't make mistakes. Brushless servos (and brushless steppers) take forever to wear out and thus need a lot less maintenance.

There, that's an earful. I've actually never looked really deeply into the hobby grade machines because they're not up to the kind of work I want to be doing, but I can give you a pretty good overview of any company making sub-ind level routers and up as I've spoken to nearly every one of them and gotten customer reviews for most as well. Brock Poling38875.6787962963

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Jeff for around $6K I got a KG-3925-G from K2, that includes upgrades to better ballscrews, a controller, motors for the 3 axis points. And an adapter for a porter cable router with dust collection. They introduced that model for Guitar Makers specifically, it has good tolerances and even Bob reccomends it

I had to add a computer (bought mine from Dell), Rhino and RhinoCam.

The machine is shipping out the 19th of this month and the last cost is I have to build a table for the machine, all told I figure it will be around $9k.

I looked at various duplicarvers and for the money and hassle CNC seems like a better way to go, You can't really make 'parts' with a duplicarver like you can with a CNC machine. My main goal was to make parts, tools and intricate things like bridges, fingerboards, mortises, tenons and rosettes and introduce some stability in my building. The idea that I can make the same bridge or say headstock over and over without variation (or very little) is a boon to my building.

It's a good deal of investment up front but if I was going to spend $5k for a duplicarver I'd certainly do some research on CNC to see what a little more can get me.

Cheers

-Paul-

_________________
-Paul-

Patriot Guitars

If I may be blunt:

CNC machines aren't the solution for everybody, but those duplicarvers (at those prices) aren't a good idea for anyone.

There's nothing on that site that couldn't be built in a weekend for under $200.

_________________
John Watkins
CNC Guitar Parts

Paul,

Thanks for the information. Any information I can get, helps me understand what is available, and what should be avoided.

Sounds like your setup is going to take your consistancy to the next level. I can argue about the innate beauty of a hand-crafted item such as a bridge, which I enjoy making. But each one is hard to duplicate in relation to previous ones. And, it seems like the buying public is looking for that level of consistancy, or they see the product as "inferior", even though it may function or sound just as good. Achieving that level of consistancy would be one less pressure to deal with, and allow for more time for fine tuning of an instrument. (Just my viewpoint)

[QUOTE=John Watkins] If I may be blunt:
[/QUOTE]

Yes you may, and please be! I am too ignorant to know better, so I need someone to tell me, "Don't do that!" Infact, at this level of knowledge I probably need someone to send me a detailed shopping list!   

Thank you all for the input.

Jeff

I have a Terrco duplicator and bought it for the express purpose of duplicating parts. I have used it for woodworking and guitar building.

At one time I wanted to build archtops but after two decided that I like playing archtops better than I like building archtops.

The cost of CNC has come down tremendously and is very attractive but still is an upfront investment that needs to be thought out carefully. I am not opposed to CNC woodworking machinery at all...for 15 years I imported and distributed across North America NC and CNC woodworking machinery. In the late 70's I sold the first 6 axis CNC Shoda router in the US.

I sold everything from automatic moulders to complete manufacturing lines for windows and doors. One window line that I sold to Anderson Window would make a double hung window unit from raw parts to shrink wrapped finished product in 38 seconds...To load everyone of the stations in that line took just under 15 minutes but after that it was 38 sec. per window!

I never intended to use my duplicator for small parts...today I use it mostly for rough carving out cello and Double Bass tops and backs for which it is a good fit.

I bought it instead of a CNC setup because I just didnt want to go to all of the effort to setup and program a CNC system. They are infinitely more flexible as to what they can do but for me I wanted a simple manual alternative that I could fold on its side (got the idea from Steve Anderson in GAL years ago) and push up against the wall.

For me I have no aversion to technology, it was actually a basic thing for me...I work as a software engineer for Microsoft's government group and when I come home to build guitars I did not want anything computerized as it is my way to kick back and do something physical, nothing negative about CNC, just what works for me.

Here is the setup I have...they were around before Duplicarver was around.



I bought my duplicator on eBay for $800.00 which was reasonable and have have gotten more than that much use out of it. There are alot of DIY plans for duplicators on MIMF and other forums if you want to go the low tech duplicator route... for me I had planned on going that route (given the fact I was looking for a manual setup) until one came up on eBay that was an attractive price in that it was less expensive than my lack of time.

Shawn,

Thanks for the information. $800 to rough out parts is pretty attractive. Have you used it for a neck, or a small item like a bridge?

Jeff

Harbor Freight carries a duplicator in their catalog for around 200 dollars, at least they did last year. Now as for the quality of it, who knows.

On another note, when I was building my CNC machine, before I had attached the motors, I noticed that it really could be converted to a duplicator pretty easy.

I have done necks on my duplicator but not bridges. I build almost exclusively classical/flamenco so I have limited use of the duplicator for it but if I am building a cello, then the duplicator does the hard work. When I say I rough out necks...In the past I did more steel strings and used it for neck then. A classical neck is so set as to style, joints and material that it would be more trouble to setup for classical necks.

While some of the duplicator vendors sell them to make routed signs, for guitars I think that they are much better for roughing out parts and not fine work.

If you look at the Gemini duplicator you have linked above, one of its features is a handbrake! This is because with a duplicator the routing is matched by a corresponding stylus that guides off of a master...while you are focusing on keeping it on a portion of the master, the force of the router wants to pull the entire duplicator carriage in the direction of rotation so you are fighting against it. The handbrake helps in that it limits forward movement but the carriage will still want to pul across the work surface. It is not a hassle and is easy to control for roughing but for fine work, it would be a real challenge (read that as if at all!).

Any machine you add into the process of guitar building is there to replace or at least reduce the time it takes to do a machining function that would otherwise be done by hand. For building an archtop guitar or mandolin, for roughing out a large amounts of wood for a cello or double bass, a duplicator does great. Where a CNC setup really shines is in a few key areas...

1. A CNC can control feed speed and control of cut that is much finer than a duplicator can do.

2. By adding a digitizer to a CNC a master part can be scanned and converted into programs that can then be re-run at any point without having to keep a stack of masters around.

3. A CNC can cut much finer patterns than is possible with a duplicator and often even finer than is practical by hand. An example is that Don MacRostie (of Stew-Mac) who runs Red Diamond Mandolins uses his "shopbot" CNC to graduate his mandolin tops (this would be impossible with a duplicator). When he binds the heads of his F-5 style mando's he routs the shape into the headplate and then inlays the binding into the headplate and then separates the finished headplate from its backer and applies to the head of his mando...just that saves how much time!

4. A CNC is much safer as you are not controlling the machine and dont have to be in the room.

Because I know and understand the limitations a duplicator has for me, I am okay with that. IF I were more actively building something other than classicals, and didnt have a duplicator, I would probably build a DIY duplicator and use it until I could afford/justify a CNC setup.

I only jumped into this CNC thread so that you could hear in perspective what a duplicator is good at, what it is not and how that compares with a CNC...all before you take the plunge either way

I'm glad you jumped in, Shawn, as it gave a much better perspective on what a duplicator company not trying to gouge you charges. At the $800 price point it compares pretty well to a CNC for price/performance if it's well made. It's all about how much time you'll save for the money you put out, but that's (as you said) not all of it.

The most obvious example I can think of of things that just aren't possible by hand is the Taylor neck joint. It's a floating neck but the joint's so tight you can't see the gap.

The usual advantage of CNC is for parts that take a really long time (carved tops, necks, inlays). And this is what most use it for, nothing more. So it's like hiring someone that works really fast on the cheap. The most overlooked advantage, though, is in the design process. If you're handy with CAD/3D software then you can use CNC to do things that most luthiers wouldn't even think to dream about. Like taking a pencil drawing of an inlay and turning it into a pearl inlaid fretboard in two or three hours.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

[QUOTE=Bob Garrish]
The most obvious example I can think of of things that just aren't possible by hand is the Taylor neck joint. It's a floating neck but the joint's so tight you can't see the gap.

The usual advantage of CNC is for parts that take a really long time (carved tops, necks, inlays). And this is what most use it for, nothing more. So it's like hiring someone that works really fast on the cheap. The most overlooked advantage, though, is in the design process. If you're handy with CAD/3D software then you can use CNC to do things that most luthiers wouldn't even think to dream about. Like taking a pencil drawing of an inlay and turning it into a pearl inlaid fretboard in two or three hours.[/QUOTE]

Man that description has me dreaming. Probably just better to contact John and have him do cnc work for me, but maybe one day.

Thanks everyone for all the great information. It is so nice to have all this knowledge and wisdom available. I appreciate you all sharing it!

Jeff

John, where can you get all the hardware such as Linear Bearings and Linear Hardened Rods for under $200 to build a quality Duplicarver?

Jeff,
I picked up the Gemini that was used for demonstrations at the GAL convention this past week (cheap). When I get it set up you are welcome to come check it out. I plan on useing it for roughing out arch top plates, necks & electric bodies.

Anthony, eBay of course!    

1/2" Thompson style bearings are only like $30 brand new, so the used ones can be had for very cheap when they show up, especially since all the CNC guys are holding out for linear guides. The hardened rods are dirt cheap from the industrial supply houses. Stop at your local scrap yard for some $.20/lb tube steel, make nicey nice with a local fabricator, and boom, yer done.

These would be ideal.

_________________
John Watkins
CNC Guitar Parts

Thanks John. Problem with EBay is not many sellers sell the parts in the quantity needed. It's not often you'll see 6 - 1" linear bearings come up in an auction...unless of course you are patient

Good tip on the hardened rods!

Called a couple local suppliers and the Thompson Linear Bearings are around $100 per for 1-inch and 1-inch hardened ground shaft is $1.30 per inch (ouch)!!Anthony Z38896.4758101852

[QUOTE=GD Armstrong] Jeff,
I picked up the Gemini that was used for demonstrations at the GAL convention this past week (cheap). When I get it set up you are welcome to come check it out. I plan on useing it for roughing out arch top plates, necks & electric bodies.[/QUOTE]

GD,

Sweet! I most definitely will stop by and take a look. Maybe Gemini will give me the "GD" discount if I buy one from them.

Let me know when you have it running.

Jeff