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Dremel & purfling jig question.

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I have read about this topic on the forum but many of the threads are a few years old.I would like help to find which Dremel tool and purfling jig would be best to buy in 2015 .Thank you for any help.

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The Dremel tool that screws into the aluminum holder and run around the edge of the plate works fine, but is a little awkward to use.  I've never used the kind that you fasten the flexable shaft into.  Just from looking at it it seems like it would be easier to handle.  Although more expensive.  You have to get a motor, flexible shaft, plus the jig to run around the plate.  With the Dremel it's a pretty cheap purchase.

 

No matter which one you end up with don't think you will cut a perfect grove the first time out.  Practice on scrap first.  One tiny slip and you've ruined the plate.  They both run at very high speed and don't care where they are cutting, 

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Yes, the Dremel jig does work extremely well, as I would imagine does the pencil style purfling cutter.

 

Berl is giving the apt information - practice is paramount with (I imagine) either style of purfling router, but the fact is that after you become used to using (the Dremel is what I use) the purfling grove becomes so amazingly easy and fast, that you'll never go back to hand cutting it again...

 

Since the Dremel follows the outer edge (the outline) for its accuracy - the outline must be finished well first - as once the groove is routed in - its over.

Around the edge also needs to be finished to one specific depth or height, since the groove is also going to be cut to a specific depth into the plate, depending on how you set the bit in the cutter.

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In other words I really like the Dremel router, the one that the Dremel tool itself screws into...

Mine has been altered slightly to accommodate my personality - but I've been using it for a very long time.

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I would recommend using a footswitch to stop and start the Dremel. The start of the cut needs to be plunge cut while the tool is running, but at the end of the cut it's better to shut the tool off before removing it from the groove. As pointed out, one little slip and *#!^$$$.

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Michael, do you mean the type of footswitch that comes with a Foredom?  That is, one that gives variable speed?  Thanks in advance, Dan.

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An old foot control salvaged from a sewing machine is what I use. My biggest issue is finding cutting bits the right size. Mine are .051" so I have to adjust then make a second pass to get the purfling to fit. You also need the cutter that cuts down, not up. the one that cuts up will tear out the edges of the cut.

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An old foot control salvaged from a sewing machine is what I use. My biggest issue is finding cutting bits the right size. Mine are .051" so I have to adjust then make a second pass to get the purfling to fit. You also need the cutter that cuts down, not up. the one that cuts up will tear out the edges of the cut.

 

Yes, the correct bit, and all the other minutia that goes along with doing this operation...

 

I'm thinking that a new post or thread - covering all of this, information wise, would not be at all a waste of time or effort for any of us.

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An old foot control salvaged from a sewing machine is what I use. My biggest issue is finding cutting bits the right size. Mine are .051" so I have to adjust then make a second pass to get the purfling to fit. You also need the cutter that cuts down, not up. the one that cuts up will tear out the edges of the cut.

MSC tools sells upcut spiral mills in carbide in increments of .oo5"   I have  .050 for violin and .060  for viola.  I also like fiber purfling which may not be the cup of tea for many of you.  At least it seems to be 1.25 and 1.50 mm and pretty reliably constant in thickness.

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I have at least five Dremels and only one has bearings close to good enough for purfling. The dremel flexible shafts are fine except that they don't swivel. I use a Foredom with a home made guide and the foot control. Upcut bits work fine for me if they are sharp and I haven't found a convenient source for downcuts in the size I need. I do run my purfling through my slip roll to make it fit the groove.

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Thanks to all.  A new thread about cutting purfling with a Dremel or Foredom would sure be useful for me.  Captainhook, could you explain how you made your guide for the Foredom?  I found one online but it's two hundred bucks plus shipping and that's more than I can afford.  I did see a picture of a home made jig here but it didn't have any dimensions or directions on how to make it.  Dan.

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I just figured it out as I went. The main part is wood with a V-groove and hose clamp to mount the handpiece. At the bottom is a combined edge and depth guide, adjustable for the distance of purfling from the edge. The depth is adjusted by moving the handpiece and the cutter. I don't have measurements because I didn't take any.

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After 1 hand cut purflng channel sesson I said "there has to be an easier way".  M. Darnton"s website is where I started.  I used a Dremel 300 motor, King Craft flex shaft cut down to fit the Dremel-  I clipped some shredded flex cable from a malfunction of the King Craft motor and fit it in the Dremel.  I used the Dremel circle cutter threaded piece without the metal circle cutter pin piece.  The cable fits in the Dremel but I used duct tape to hold the cable in the motor because it won't tighten but will spin fast.  Tape around the plastic threaded circle cutter piece for holding and stability.  The motor hangs about 3 ft above the work table.  The cable should be kept straight-no twisting/kinking.

 

The base was made from a section of aquarium made of plexiglas.  Cut a section 1 3/4" from the fish tank.  Cut a side and bottom section together, they are already fused together.   That will be the 90 degree base.  I encased the flex shaft hand piece into an old Skil battery hand drill casing, scrap the guts- keep the outer casing and make the flex shaft fit into the case.  Mount the casing to the base made from the aquarium.  Make adjusting height slots and super glue a tab to have a consistent distance while routering purfling groove.  I routed 7 violins this way.  Use incremental depths to reach the needed depth or you will burn or break bits.  I lost 1 bit. 

 

Making your own purfling channel cutter from scratch and scrap is every bit as hard as trying to understand what I just typed here, but if I gave you any ideas for you own design then I have succeeded,  good luck.      

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.......while learning about other violin makers building technique in regards to purfling marking, cutting, routing etc. I feel I should add an opinon for safety/goof-up purposes. 

  First, some don't install purfling until corpus assembly is complete.  A router may prove more hassle than worth because of height and wobbleliness issues.  A mistake is very possible. 

  Second, I realize most or some build with a 1 piece mold instead of a 2 piece mold like me.  I can tell there is some rib flexing with a one piece mold.  If routering purfling grooves first before gluing plates to ribs one could throw things off by a mm or 2 because of ribs flexing in and out from the 1 piece mold.  If you want the work to be precise routering channels doesn't seem a safe way.  With a 2 piece mold the ribs are tightly wrapped around a full height mold- it's more of a sure bet everything will line up before and during assembly. 

  I'm not 100% sure of this because I havn't used a 1 piece mold for assembly or installed purfling after assembly but a little flexing of ribs on the mold happens on the 2 piece mold and I'm just thinking there would be more flexing with the 1 piece mold, throwing things off a bit.  

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