# Instruments and Equipment > Builders and Repair >  dupli-carvers

## ZZCHOP

Hey guy's:I was wondering if anyone out there might be able to give me a little info on duplicater machines.I've been shopping around a little and have found a machine called the Marlin CM-624.If anybody has one of these carvers or knows of a better one for the money please do tell.The company who makes the Marlin is(terrco).They said a lot of guy's who build both guitars and mando's use this machine.I beleive i saw one at Dudenbostels site,but i was'nt sure if it was a marlin or not.  thanx in advance!   Jim

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## Jim Hilburn

Dude uses a Shopbot cnc now, but used to use a Marlin.I got the 24" model, but wish I had only gotten the 12".That's all you need for mandolins, but if you think you'll ever do archtop guitars, you would need the bigger one. I think the 12' would be more rigid than the 24" because one rail rider can get ahead of the other and the longer length between the feeler and router can get a little deflection if you make a quick move ...,but even then,this thing does a great job when it's set up right.

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## rose#1

I use the cm-614 it does a pretty good job the only complaint I have with it is you have to keep an eye on the pivot screws sometimes they come loose which will throw off the height of the router or stylus. had to scrap a top due to this but for the most part it works fine. I used to use a craftsman router recreator. it is a little cheaper if you can find one but it rides on rails and a cable not the steel bars like the marlin. they dont make the craftsman any more but you still can order all the parts to build one yourself I think it is around $400. the marlin cost me right at $1000.00

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## ZZCHOP

Thanks guy's:I don't mean to be nosey;but i was wondering if you got your machines from terrco or is there another dealer out there some where?I have been surfing the web and have found lot's of discriptions of these machine's,but i havent found any retailers other than terrco.I was also wondering about how long it takes to do a mando top.I've been making some arch top guitar top's for(begged me not to tell)somebody else and it is extremely time consuming.It's got to the point now the guitar tops are cutting in to my quality mandolin sawdust producing time;and that hurts my feelings.thanx guy's       Jim

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## Jim Hilburn

I got mine from Terrco. About $700 as I recall.I already had the router that works with it.

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## ZZCHOP

Jim:How long have you had yours?Terrco quoted me $1050.00

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## Jim Hilburn

About 3 years.

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## P Josey

Here's a site you may find interesting. I've built one of these and it works excellent. #For those of us on a budget, this cost me about $225-$250 USD. It took only a morning to build. The designer says his the biggest users of this are instrument builders. Just another option # Here

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## Lynn Dudenbostel

I had a Marlin (now Terrco) and used it for several years. I hated running that thing! It was the part of building that I would always dread. Nothing wrong with the duplicator, but it would throw dust/chips everywhere, and hanging onto the stylus with my right hand, and the router with my left was very tiring. Also, after running the thing for a couple of hours, I'd find my left hand shaking from the high freq. vibration in the router, much like running a leaf blower for a while. Long term, this isn't good for you.... not if you want to still have good use of your hands in your old age! I did use a good Porter Cable router, so the vibration was minimized as much as possible. I'm now using a ShopBot PRT48 and loving it! Don't get me wrong, the Marlin is better than carving by hand. If you are just building the occasional mandolin, the Marlin is fine, but for someone building quite a few instruments, there's nothing like CNC. 

Look for a used Marlin. I've seen older ones go for $300 and newer ones around $500. They are faily plentiful, and with more people switching to CNC, more used ones are out there. A couple of years ago, Steve Smith and I went to the IWF show in Atlanta. The CNC company booths were really busy. The Terrco folks were as lonely as the Maytag repairman. The Marlins still have their place, especially for the hobbiest and lower production shops. Heck, I think even Steve G. still uses a duplicator, and he's not exactly low production compared to some of us!

Best regards,
Lynn

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## ZZCHOP

Thank's everyone!P.Josey that copier sure would save a few dollars for diapers and baby food!My wife just found out she's expecting;due in september.We already have two boy's and her docter say's she may be carrying twins.Maybe i could give them a mandolin neck without finish on it for teething!  Thank's again all.    Jim

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## P Josey

Lynn, what would an entry level ShopBot with programming to do mandolin top and back plates cost. Do you need special training to program them and how user friendly are they? It does seem like the way to go but do you think it justified for low production builders.

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## Lynn Dudenbostel

Look at www.shopbottools.com They have prices there. Last I looked, the smaller table top model (plenty big for mandos and guitars) was $4995. You'll have to supply a PC, but it doesn't take much of a computer to run it. I use an old 100 mg Pentium dinosaur. It will run it at full speed. You'll probably want a digitizing probe to probe your patterns. That's another $250, and add another $300 or so for a router. You can spend a ton on software, but I use the probe with the software that comes with the "bot and also Vector CAD/CAM that use to come with the ShopBot. They now have better software packaged with it. Only thing I use Vector for is creating offsets for making larger binding channels in my peghead veneers. To "draw" F holes and peghead veneers, I use CorelDraw. If you don't mind an older version, you can buy 8.0 on eBay for $25. IT's all you need. But, you can spend several times the cost of the machine on software, if you are so inclined. I've spent $25, and that's all on software. Another possibility is to find someone who is a whiz at CAD/CAM and pay them to create your programs. That might be the most cost effective route. Any .dxf file can be converted using the ShopBot software to the proprietary .sbp ShopBot code. It's quite user friendly and the support from the people at ShopBot is nothing less than amazing. If it's a problem with something besides the ShopBot, like trying to figure out how to trace a bitmap drawing with the bezier tool in CorelDraw, ShopBot hosts a great forum where you can get a lot of help with other issues. There is a learning curve and some inital set-up time. 

Is it cost effective for the small shop? Depends on how many instruments you build a year. If I were only doing 2 or 3 a year, I might not be tempted. I turn out about 12 instruments a year and I wouldn't think of trying to build without it.

Lynn

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## Michael Lewis

I ran across an interesting duplicator at the NAMM show, do a google search for  multicarver. It's not real cheap but it is well made and of a good design for this sort of machine.

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## ZZCHOP

Thanks every one!Michael i went to your site and looked around.I had remembered someone saying you built archtop guitars,but i had no idea they looked that good.If i had lynn and Jim's money i would go ahead and get an excel,maybe a signiture,and a wing feather!Michael your wing feather made me drool on my keyboard.Being serious they look superb.         Jim

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## ZZCHOP

Guy's thanks for all the good info.I went with the marlin cm-624.I will probably be needing all kinds of new questions answered now.
 Lynn i wish i had of known you was selling your old machine.I don't live to far away from you.
                 Jim

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## Lynn Dudenbostel

I sold it a couple of years ago. It's long gone. Ron Cole is putting it to good use now!

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## Michael Lewis

ZZCHOP, thanks for the comments, just let me know when you want one and I'll get you in line, I know the boss.

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## ZZCHOP

Michael:I'm still waiting on Lynn to loan me #his spare pocket change.Legend has it both,Lynn and Jim Hilburn uses their uneeded fifty dollar bill's to back with 220 grit 
sandpaper,for sanding inside that dreaded scroll area.
 # #just kidding guy's don't drill me # # # #Jim

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## Jim Hilburn

I've found that hundreds hold up much better than the fifties. I know, you'd think they would use the same paper on all the money, but they actually use the much heavier stuff on the higher denominations.

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## Dave Cohen

I'm surprised that there isn't much discussion re the Gemini carver. They had a booth at the ASIA convention last summer in Maryland. The Gemini is very sweet compared to the Terrco/Marlin. Last time I saw a price, it was around 3K. That puts it right between the Terrco and the Shopbot. Attainable for those who aren't planning to get bigger or build full-time, and a good intermediate alternative for someone working their way up. Also remember that the Shopbot is at the low end of CNC. One builder I know has gotten one and thinks that it is just fine. Another thought that the Shopbot just wasn't precise enough, and went for something costing twice as much.

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## ZZCHOP

Jim:I for one am certainly glad you actually keep those hundreds in possesion long enough to gauge the thickness.I find it hard to keep em long enough to get a caliper any where close to em!Dave:I searched pretty hard for carving machines,and i can't remember seeing any of the gemini's on line.I was just wondering if you saw the one at the show in action?Actually most of my searches came up with shopbot and terrco-marlin.
 I was also wondering just how precise you can get with these carvers;and Jim since you are already using a marlin maybe you could suggest some good bit's.
 Guy's i know this thread has went on a way's but i have many more question's.I feel like a kid in a candy store.
                  Best,
                     Jim

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## Jim Hilburn

I've used mine just to get rid of the bulk of the excess wood, and rely on "other means" to bring it home. Jamie Wiens has a home made carver and he says he cuts his scroll binding rabbit's with it. I can't imagine trying that with my machine. I actually need to detail the scroll ridge on the templates and work with a smaller probe-bit to get the scroll a little closer, but this thing can quickly remove wood that you wish was still there is your not careful.
 I made a template for the neck and roughed out one,but that seemed kind of scary,and it's not that much more work to hand shape them. My problem is having the time to experiment with it more to see what I can do with it.
 As far as the $ is concerned, I think you have me confused with Michael Lewis.

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## P Josey

I have the same shop built carver Jamie Wiens has. The stylus holder in this carver is an old 1/2" drill chuck and my router is a Porter Cable with a 1/4" chuck. I'm on my way to making a point here. The cutting path is slightly larger than the stylus. In other words, a 1/2 " router bit will cut slightly larger than 1/2"". I took each of my bits and plowed a path. I then went to the local machine shop where they measured the plowed path and turned the stylus' to match. (.147"stylus-.125" bit) This way I have much improved accuracy. Jamie suggested this to me when I asked him about bits. Something to consider which ever bits you decide on.

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## Lynn Dudenbostel

So far, after almost 3 years with the ShopBot, I've not found accuracy/precision to be an issue. I cut a channel in my peghead veneers to "inlay" my binding and this is pretty precise work. The ShopBot comes thru with flying colors. I will say, in light of the fact that you have to assemble the machine yourself, ultimately the accuracy/precision is dependent upon how well you align parts during assembly. I use a 1/16" solid carbide bit to cut my veneers, and I believe I could run the program 50 times on the same part and have no more than 0.001" to 0.002" error. Sure, a servo drive unit is accurate to 0.0001", but you are talking a lot more money too, and face it, we can't hold those kinds of tolerances with wood. In practical use, I find the 'Bot to hold much tighter tolerances than claimed by the manufacturer. 

I've seen photos and ads for the Gemini, and I think Steve Smith in Texas has one. Personally, I find $3000 for a manual duplicator to be way too high in light of good CNC being available at $4995! I would probably opt to attempt to build a manual duplicator before I spent $3000 on one.

Lynn

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## P Josey

Lynn, I was kinda wondering if you have your old graduation templates kicking around.I thought maybe.....Oh,never mind.

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## ZZCHOP

Although i know it's possible for a duplicater to cut scroll binding rabbit's,somehow my brain can't process the info i'm trying to make it believe.Lynn i went to the shopbot site after you had posted earlier,and watched their video,i was simply dumbfounded.I've watched a few machines in the past duplicating several gun stocks at the same time and i thought they were on the leading edge of technology,but i guess they were just stoneage compared to some of the cnc's they have now.
 If any of you guy's have pics of your carver's in action i would surely like to see them.
 As i read all the good info you guy's are leaving i kind of wish i had of sprung for a cnc machine,but i don't exactly have Mr.Hilburns extra cash laying around,so i suppose i should humble myself and be thankful that i was able to get the marlin-terrco carver(that won't hurry up and get here)I still have a bunch of questions but i will hush for now and quit being a threadhog.
 # # # # # # # # # Thanks guy's,and best to all
 # # # # # # # # # # # # # # # # # # # # # #Jim

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## tope

I built the duplicarver and found that it does do a very good job. Make sure that you build out of at least 3/4" particle board for the base. Plywood doesn't make it. I had to rebuild mine and gained a lot of accuracy. Very happy with it.

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## ZZCHOP

Tope:How precise can you get with the carver you built?Some one posted earlier,Jim Hilburn i think,and said rabbits for scroll bindings could be cut on the type machine that you build yourself.Let me know about your experience's with differant bit's you have used also.
                  thanks,Jim

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## Michael Lewis

I'd like to see this. You know, all the accuracy you can get is directly related to the accuracy you put into it. The holding fixtures you make, the flatness and stability of the table, the 'tolerance' inherant in the machine, etc. are where the accuracy starts to slip away if you let it. Binding channels on a CNC might not be unreasonable, but probably not reasonable with a duplicator. Please show me I'm wrong.

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## Chris Baird

I've got a pretty well built home made duplicarver but I've never been able to get better than .020-.040" tolerance in the side to side cuts. The depth of cut is about twice as accurate(if I keep my hand off the router). My table isn't perfectly flat so that is part of the problem. The carver is big requiring a flat table of about 4'x 5.5'. That is really a huge area to try and make dead flat. If you are going to buy a duplicarver get the smallest one that will do the job as building a flat table is difficult. But if I ever do get the whole thing flat I could duplicarve archtops or something even bigger. Duplicarvers work as a complete system and all parts must be set up perfectly in order to get good accuracy. It is difficult trying to figure out which part of the system is causing the registration discrepencies.

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## thistle3585

Chris,
CNC shops level their tables by using the router itsself by making however many passes needed to go over the entire table. So, if the template side is "higher" than the carving side, you should be able to level the carving side by letting the stylus run on the template side of the table. Does that make sense? 
Also, if the table is off a little bit, not only is it giving you a poor tolerance, but the bit is cutting at an improper angle to the piece. This may cause vibration, tearout and other problems.

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## thistle3585

Found this link while looking for some new bits. libery mills

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## ZZCHOP

Thistle:I went to the liberty mills site and had a look around.What caught my eye was the fact thier machines come fully assembled and has software included.I also noticed thier two smaller models have little adjustable feet.
 If i had of seen these before i ordered the terrco-marlin i would have been tempted.They sure do look like nice capable little machines for the money.
 #Liberty's desk top cnc machine is $1995.00 and i just gave $1050.00 for a manual carver that i still need to build a table for.Something about this latest info makes one of my eyebrowe's keep rising. # # # Jim

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## Lynn Dudenbostel

There's a Marlin on eBay right now. The reserve hasn't been met. 

http://cgi.ebay.com/ws....y=57122

I looked at the Liberty CNC's. They don't give much information on the web site about them. I see they are located in TN. I'd want to see one in person before putting my money down. I've seen more than one that was more expensive than the ShopBot and much lighter built. A CNC that has problems could be a real nightmare, and with the availability of cheap micro-stepper motors, a lot of people are trying to throw together medoicre machines. Not saying that is the case here, just not enough to make that decision on the web site.

Lynn

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## pathazzard

Sorry for the length but this is my first post. I just stumbled across this thread and wow am I happy! I got mandolin addicted a year ago at the first SPGBMA I had ever been to, and got the builder bug after a friend let me go with him to Tim Scheerhorn's shop because he was building a resonator guitar for him. After seeing the pix of Lynn Dudenbostel carving with his marlin I ordered the parts and plans to make my own duplicator from a company now called copycarver. The thing looked foolproof (a good thing for me). But as luck would have it, I ended up with a ShopBot PRT48 and somewhere on the web after that I saw another picture of Lynn using one (can't seem to find them now). I haven't used the digitizer yet because I'm still finetuning my master templates and trying to figure out how I can mount and register the top and back plates so that when I turn them over to rough out the insides they will be aligned and repeatable. It may seem like overkill and the learning curve is killing me. But down the road it's gotta save a bunch of roughing time and it should allow me to be consistent. I know I can't stop with one mandolin and I'm real excited about trying different tonewoods (and having more mandolins!) I'm really curious too about doing the scroll rabbet with CNC. Lynn have you thought about that one? What's really frustrating me is that I'm really wanting to finish my first mandolin but now I feel like I really should spend the time to take advantage of my equipment.

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## Lynn Dudenbostel

I haven't refined things to the point I'm routing the binding rabbet, but I do my peghead veneers on it. I'll try to round up a couple of photos of how I fixture my tops and backs on the ShopBot for you. Might take a couple of days, but it might save you a bunch of time. Pretty simple actually.

Lynn

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## thistle3585

Patrick,
There are several websites that have discussion forums on all aspects of operating CNC equipment. I would encourage you to check out some of these sites. Offhand, here are a couple sites.
www.cnczone.com
www.woodweb.com
www.cncworld.com
I think that the proper initial setup can really make everything run much easier. The two primary things that I did when setting up mine was to divide the table into sections with a vacum system and I built a jig system that automatically centered each part in any of the sections I wanted to run one in. I'm not sure if you can put a vacum table on the PRT 48 since the table itsself moves.
If you want more info on the jigs and such let me know.

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## Jim Hilburn

This is another thread that I'm glad came along. Made me think of the things I needed to do to get the rig more dialed in.This morning I worked on the arching of the template to even up some differences from side to side.This should eliminate some extra work on the actual plate. Here's a pic of the whole thing about ready to go. I enclose the whole thing with cardboard and boards to try to catch as much of the wood chips as possible. Like Lynn say's ,wood goes everywhere.

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## Lynn Dudenbostel

The PRT48 ShopBot has a stationary table, so there is no problem with setting up a vacuum system. The new table top model ShopBot has an X axis that moves and could present some problems. So far, I've been able to work around using vacuum fixturing. Remember, double stick tape can hold a lot od smaller parts like peghead veneers!

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## Jim Hilburn

Here's a close-up of the template. I just detailed the scroll ridge a little more, and added the aluminum fence so I don't rout off the scroll button. It's embarrassing, but before I had a bunch of drywall screws sticking up to do that job. The plywood around the mold is to keep from falling off the edge and rounding the corners of the plate.

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## pathazzard

My PRT48 has the six horse vacuum blower mounted in a two zone configuration. The first cut file I ran was the plenum board. One thing I realize when I made the table was that you actually have about 54" of travel in the x axis, so I could have made my table bigger. I'm dreaming about someday adding a 4th axis by putting a stepper motor on the right end (running up the y axis)and a tailstock so that I can do some rotary machining. Look out mando neck! By the way, I saw where ShopBot is having what they call a Jamboree sometime in March at their plant in Durham. I understand that the last one had a subgroup of musical instrument makers. Did anybody here go or are going this time?

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## Chris Baird

For comparison sake what kind of tolerances for pecision are folks getting with their duplicarvers. After my plates are rough carved inside and out I've noticed a variance of about .015-.020" in thickness in places from plate to plate. I'm trying to decide if that is normal or if I should strive for more accuracy.

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## Jim Hilburn

Here's a follow-up on my earlier post. I just finished doing the outside of a back. It's still strong,but this is as far as I'm comfortable with. I will next use the old Siminoff sander in the drill press trick, but only to smooth the rough texture left by the router,not to try to do any shaping. Then ,I'll use the Saf-t-planer to establish the rim thickness,and blend that into the main arch. Then I'll flip it into a holding jig and rough out the inside. Then I have what I consider to be a roughed plate ready to work with all the conventional means.
 After a few passes,I pulled the plate out and thicknessed the height of the scroll button in the Performax.

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## pathazzard

"Saf-t-planer to establish the rim thickness,and blend that into the main arch"
Uh Oh. The plate needs to be exactly the same thickness all around the edge (except for the scroll area) and put on the rim before binding rabbet and then shaped to the recurve area after the binding is in place? What WAS I thinking? My top plate is as thin as .180" in a couple of places at the edge. Can I salvage it? NOW I seem to remember that from the Siminoff book.

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## Bill James

Here is a method of fixturing that I've used when making odd shaped models that had to be re-fixtured for machining the opposite side. I've had good success with this method and it could have some merit for making mandolin tops on a CNC router.

1. The top of the top is machined and two tabs are left with a locating hole in each tab. This top will not be used on a mandolin, it's to be used in the construction of the workholding fixture so an inferior piece of wood can be used.

2. The fixture itself is a large stable block of wood or plastic with a cavity pocketed out and two locating pins installed to accept the holes in the "sacrificial top".

3. The cavity is filled with a castable material and the sacrificial top is coated with a release agent then pressed, top facing down, into the material. After it cures, remove the top. Now add a vacuum hole. The castable material should be soft enough to privide sealing properties and there are many such materials available.

You now have a fairly permanent vacuum fixture for cutting the back side of the top.

As far as programming is concerned, digitizing works and it's doable as Lynn has showed us. However, it does have some limitations. If a person has CAD skills or possibly a friend or someone else who does, the cats PJ's would be to create a solid model of the top and generate the toolpath from it. The advantage is that once created, it can be changed and edited with a minimal amount of labor. Also "two dimensional" features such as binding channels etc. can be added to it and incorporated into the toolpath. This is where CNC technology really starts approaching critical mass.

I think it's great that you guys are incorporating CNC into your processes. Whenever I show someone a CNC machine in operation that has never seen one before I love to look at their eyes. You can just feel the wheels turning in their head. 

Can you relate?

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## thistle3585

I guess I don't understand the building process, because I would think you'd cut the inside first then flip it over and cut the top and that would alleviate having to make some complex jigs.

Hey Jim,
You, as well as others, have mentioned the excess airborne dust and woodchips. What about putting a dust skirt on the router and hang a vacum hose on a spring from above. That way the hose would move with the router. Might make it a cleaner process. Not to mention much safer.

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## Jim Hilburn

My blanks are often wedges. This one is a wedge that's thicknessed to near final dimensions, so it is flat once flipped, but that's not always the case.You would still need a hold-down system,and that's built into my holding jigs.
 I would love to have a vac system that work's ,and I've tried several ways, but the chips come flying out in every direction depending on which way the router is moving, and I've found it easiest just to sweep and vac it all up when I'm done.

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## ZZCHOP

Hi all!
 #My machine finally arrived yesterday!I had opted for the 624 like Mr.Hilburn's carver.Money i suppose,really made up my mind for me;and the fact i have babies on the way.And i also still have a bigger house to build(no more room at the inn).If money was'nt a problem i would have gotten one of the shopbot's since my bro-law is a pc tech.
 #When my carver arrived i was ankle deep in chips from some top's i was graduating.It was the very answer to my problem and i was so far behind(timewise)all i could do was look longinly at the box.
 #when i finally got to open my box i thought it must have been missing some parts or maybe had a hole in it or something.It wasnt until i found my istructions that i began to understand.
 # To all that have built a table large enough and level to hold a 624 tell me how you did it please.That sure is a big space to build flat and level and i know that is where the precision of the machine really lies.
 # Jim your pictures helped me a lot!It kinda looks like your table is 2x6's and ply.I've thought i might build my table in that same manner and maybe add caster's so i can roll it out of the way for that dreaded cleanup every one is talking about.
 # Thanks every one for all the reply's.They are great!
 # # # # # # # # # # # # # # # # # Jim

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## Michael Lewis

Jim Hilburn, your machine looks a lot like the old Marlin that I use, except mine is green. Your fence around the scroll button makes me think you are not using a cutter the same shape as the tip of the stylus. If you use a stylus tip the same shape and just a tiny bit larger than the cutter you will not cut anything on your work piece that is on your pattern. In short, it will leave the desired shape with a very slightly larger scroll, which leaves a bit more wiggle room when it comes to matching up everything.

I put an axle with a pulley at each end and mounted it with pillow blocks to the castings, then ran a thin cable around each pulley and anchored each cable end near the mounting blocks of the guide/bearing shafts. This keeps each side even, when one side moves so does the other, and in the same direction. Now I'm thinking about upgrading to acme screws and flat rails with precision bearing blocks. This has already started the slippery slope toward a full blown CNC.

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## RI Jim

There are a couple sets of plans for homemade dupli-carvers over at the MIMF that no one has mentioned yet. This one cost me all of about $75 MAX. 6/4 Birds-eye maple that didn't have enough figure to be used for instruments, some 3/4 inch dowel stock , a B&D router off E-bay for $25 , bought 2 back-ups as well so that figured into the price, a sardine can with some melted fishing sinkers for a counter weight. Cheap, easy to make, and gets you 80% there. John Sargent came up with this design, and it works as good as the other ' non-CNC ' machines for a fraction of the price and for something that doesn't get used everyday, economics plays a role in ones decision making .

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## RI Jim

Since that picture was taken, the tracer was made adjustable with a teflon tip . Everything else has remained the same and it works just fine.

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## Jim Hilburn

Micheal, I use a 3/4" ball probe and 3/4"round bit, and that was what Terrco recommended. The way I made my template, it would nick the scroll button because of the round bit. That's why I fenced it off,just to be safe.

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## pathazzard

For those who are interested in making their own duplicator go to www.copycarver.com the plans are simple and it's cheap to build, plywood, pulleys, and pillow block bearings. I ordered all the parts for under $100. You could make any size you want by just scaling dimensions. It uses a 'swing box' design. Jim if you don't have a lathe, one thing I think they mention somewhere is how to make a stylus that exactly matches your cutter. You lower your cutter into a block of hardwood, then cast a low melt alloy in the cavity. Voila, an exact match. If your cutter and your stylus are the same you should never get into an area that's not on your pattern. Pat Harrell

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## Gavin Baird

I built my duplicator carving unit 8 years ago and it produces high quality carvings for me. One of the problems with this sort of machinery is that one tends to use carving bits that are too large. The tendancy of the bit is to pull the cutter into the wood and as a result the tolerance of accuracy is reduced. The way I go is to select carbide for the Maple and high speed steel for the spruce. You can hone both the cutters to a really sharp edge using diamond for the carbide and also for the high speed. For the best results 1/4" dia cutters give the most accurate results. For those who want to build their own machine I would suggest that you look for Thompson Ball Bushings and their ground shafting for the bed of the carver. The rotating shaft should be robust [1 1/4" dia], the arms are best from steel tubing [1 1/4" dia] and the conecting arm wants to an absolute ridgid member. If any one wants additional photos, let me know and I would be glad to supply...G

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## Gavin Baird

next image

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## Gavin Baird

This was my rendition of the ball bushing and far too much work to justify the end...G

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## rmoss

Gavin I would love too see more pics of your carver if you have any.

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