Simple Pantograph

[Dave Higham]

Dom, adjustable in both directions. If you look at Keith's you will see how he has done it. Actually, only one needs to be adjustable. For instance you could position the cutter exactly where you want it on the workpiece by moving the carriage around, then position the (adjustable) stylus in the corresponding position in the mould.

Rod, the same sequence of photos are in my 'Tenor Ukulele (or two)' thread on TLC which has ground to a halt but will be continued when I can get round to it.

[Dominic]

Thanks Dave, I wouldn't have it was needed and would gone ahead and made one like yours. Experience beats theory.
Dom

[Allen]

Just an update on the "Friendly Plastic"

I placed an order for 1 kg from the Pommy ebayer and it arrived in about 12 days. Not to bad considering how far it was, and all the delays with getting anything from down south because of the floods. Landed on my door for just over $53 AUD.

[Dominic]

I got some of this FP from LMI to fill an order a while ago. The jar you get is 18oz (0.5kg) which is plenty unless you want to make a million molds because if can be reused. It costs $28.

So does this mean we are going to see a bunch of pantograph jigs coming from these pages soon?

Dom

[Allen]

It's on the to do list. Just don't know when I'll have the time to do what's on that bloody list though.

[Dominic]

I know what you mean Allen, I keep finding bits and pieces i have collected for projects that I had forgotten about. I got the runners for mine about 8 months ago and got an air power die grinder from Blue Creek about 5 months ago. At least when inpiration strikes I have all the bits to get it done quickly. Actually the die grinder is really good and I have used it for free hand inlays. Really smooth unlike the dremel which vibrated all over the place even when new.
Dom

[Allen]

My Dremel leaves me wanting as well. Gotta go shopping now.

[Puff]

Using the Flexishaft handpiece on the cutter side with the Dremel itself hung from the ceiling directly above, on a very slightly tensioned bungee cord, may help some.
Word is that some/most hot melt glue sticks are 'friendly plastic'.

[Allen]

I've been looking at a bunch of Duplicarver machines. Commercial and home made, and I'm wondering if there is some good reason why you would require the carver and pin to hinge independent of each other?

I can understand that it would be a nice option to be able to adjust the placement of the stylus in the x - y axis to aid in line up, but having each of the parts hinging independent of each other seems to complicate things, as well as introduce unnecessary play into the structure. Hence the requirement to rack the hinges.

[Kamusur]

Just a footnote on the "pantograph or copier etc"

If you were to make one of the arms say like a piece of meccano ( many yerars ago i used plastic faux meccano with holes predrilled ) then you can control the scale of the copy or replicate very easily and in exact mathematical formula.ie along the arm you can change the point of copy to trace or scribe to reduce. It is hard to get great accuracy but it is a heap of fun ( and environmentally friendly way to up or down size things instantly and silently).

Steve

[Dominic]

I've been looking at a bunch of Duplicarver machines. Commercial and home made, and I'm wondering if there is some good reason why you would require the carver and pin to hinge independent of each other?

I can understand that it would be a nice option to be able to adjust the placement of the stylus in the x - y axis to aid in line up, but having each of the parts hinging independent of each other seems to complicate things, as well as introduce unnecessary play into the structure. Hence the requirement to rack the hinges.

Allen, I've thought the same thing. Can't for the life of me come up with any reason but as i haven't built one yet I could be missing something simple. But if both stylus and router were fixed on the same hinging top section that would seem to be perfectly adequate. Lower the stylus into the pattern at the same time the router makes its first cut into the inlay.
Have you been looking at larger duplicarver machines Allen? I've seen some pretty simple home made ones for roughing out archtops and solid bodies on Youtube. One was just basically 4 wooden beams about 50x50mm fixed at the 4 corners with pins so they swivel. Router and stylus at the end of the long arms that hinged enough at the other end to allow 3d carving. The non router end was fixed to the bench and the work was moved long wise underneath while the swivel gave side to side movement. I was impressed with what the guy did with it. Made the commercial ones look over built.
Cheers
Dom

[jeffhigh]

I think the separation of the stylus and cutter mechanism is to allow you to set the depth of cut accurately regardless of what is happening at the stylus. the builder says that works better for inlay.

[Puff]

Dom the rocking parallelogram with a feed table variety will work fine so long as you get all racking between cutter and stylus out of play. Any vibration at the cutter head will make that a nightmare.

[Dominic]

Jeff, the depth of cut can easily be set with a dremel by adjusting how deep the router bit is set in the jaws. And with a die grinder by simply lowering or raising the whole unit in the clamp that holds it to the top section by loosening the thumb screw. Check out the pic of the McKenzie model.
Dom

[Dominic]

Dom the rocking parallelogram with a feed table variety will work fine so long as you get all racking between cutter and stylus out of play. Any vibration at the cutter head will make that a nightmare.

I wouldn't really use one of these unless i had to make tens of archtop tops and backs as I loved the carving process of the one I have made so far, it was more a mental excercise. But I'll see if I can find the youtube vid again. The guy seemed have sorted any racking issues and his setup looked really simple.
Dom

[Puff]

Dom - with respect it is simpler to make the stylus depth adjustable.

[Dominic]

Puff, I think you have missed the point or misread my post. Both stylus and router bit should be depth adjustable so different thickness fingerboards or headstocks can be cut using different thickness templates. But we are discussing whether they need to be on seperate hinged boards or not.

[Allen]

Had looked at larger units last night, but it's way too much money for what they are. Easy enough to knock something up in the shed.

There's heaps of ways for accomplishing the depth adjustment, with either the stylus or the cutter. It just seems to me that anything that you can do to minimise play in the entire mechanism is going to pay off with more accurate cutting.

[jeffhigh]

Dom, I realise that the depth can be set by varying the bit height etc.
What the split does is introduce an independance between the stylus and cutter in the vertical direction.
The hinged board which holds the cutter will always rest on the board underneath it and cut a uniform depth on the workpiece even if the stylus goes up or down (if say the template is not quite level)
Whether this is a good idea or not, I have no idea, the builder seems to think it is for inlay where you basically want 2D plus a fixed depth
I guess you could easily add a bridging piece to lock the two sides together for 3D work.

[Allen]

Ok, that explanation makes sense to me now Jeff. As you say, does it make all that much difference? I guess if you were careful making your templates it's not going to matter.

[Dominic]

I get you Jeff. But what would happen if the stylus accidentally rose up and over a section that was not meant to be cut, say between the letters of a signature or complex shape? The router bit could follow but being at the same fixed depth would cut the wood where it was not meant to. You would also have to be really careful lifting the stylus and router bit to go to the next section so as not to hit the walls of the inlay channel. If they are fixed then this would eliminate this potential problem.

I like Dave's method of making flat templates using the piece to be inlayed in the square form with FP in the vice. That should give a pretty accurate template that is level so the stylus doesn't need to run in a different plane to the wood being cut.

Anyway, all my theorising is fine but I'll need to make one first before I can be sure. I leave Warsaw today so will have a crack next weekend and check it out.
Cheers
Dom

[Puff]

Apologies for speaking out of turn but this standing in the corner staring at the wall is boring.
I thought the purpose of the proposed device was to accurately copy stuff in three dimensions, be that third dimension a cavity or a raised surface. Ergo - make an accurate pattern and copy it. Indexing can be a bit fiddly but it's a small time price.

[Allen]

OK, now Dom's got a really good point. I'm getting confused.....but beer fixes everything don't it.

Of course the key to the whole process is to have a really good template. I was thinking that measuring an accurate amount of plastic to fit into some sort of mould, then pressing in the part to be copied so you ended up with a tiny flattish brick or tile is going to make your life a lot easier.

[jeffhigh]

I've got no idea which way is better, only pointing out that Keith has gone to a lot of trouble to include the depth independance, so it must suit his method of working.
If you were going to eliminate this, you might be better off with the rigidity of a box structure like the copy carver rather than a flat plate

[Puff]

Yep - For the mold/pattern Dave's little tute toward the start of the thread is spot on. A couple of X axis and Y axis indexing points in the mold, but outside the surface to be milled, will help immensely in setting up. These things need accurate indexing as does a computer driven CNC but the upside with these is that you have the model and the subject material side by side in real time rather than in the theory/plan and "hell I hope..." world of computer driven devices.