Recently I found a 3 AAA cell battery compartment (care of ali-express) that I'd like to build into the bottom of several plastic enclosures. Its' downside is that it requires a somewhat complex cutout shape. I only have a what I'd call a "poor mans milling machine", meaning a drill press with and X/Y vise. Thats fine for simple rectangular cutouts, but not something like this. So my only recourse was to make a paper pattern, transfer it to the plastic as a visual guide, and manually mill out the shape on a piece of test plastic.
Not surprisingly, I had to spend considerable time touching up my rough "slop" cut with files to make it right. But now that I have one perfect pattern, is there some way I could rig up some kind of manual replicator? I don't means some expensive computer driven mill table. Is there some way to make a rig with some kind of "probe" on one side, that I can carefully move around the inside of my "template" cut, while at the other end a small platform is moved under my milling bit. Am I describing this right?
Not surprisingly, I had to spend considerable time touching up my rough "slop" cut with files to make it right. But now that I have one perfect pattern, is there some way I could rig up some kind of manual replicator? I don't means some expensive computer driven mill table. Is there some way to make a rig with some kind of "probe" on one side, that I can carefully move around the inside of my "template" cut, while at the other end a small platform is moved under my milling bit. Am I describing this right?
Your description sounds similar to the old pantograph used to replicate drawings. IMO, unless you have many pieces to work on, designing and building & using such a jig would probably be no easier than the rough cut & file method you used for the first enclosure. Hopefully someone has a better idea.
It sounds like you're trying to describe a "pantograph". Seed a search engine with that word - various companies have used the basic concept with milling tools ranging from Dremel machines and dental handpieces, up to full size cabinet-shop routers. Home-built versions have occasionally appeared in woodworking magazines and web sites. The smaller versions carve name badges and award plaques; the largest I've seen was duplicating signs marking a subdivision entrance.
Many years ago I played with an inexpensive version designed to carry a Dremel tool. My task was to turn out a handful of award plaques for my son's Scout troop. It took a fair amount of practice to develop a usable process and get the "feel" of the tool. I produced almost as much scrap as usable product but eventually finished the job.
Is your "complex shape" essentially a 2-dimensional outline - that might be followed by something like a "pin router" - or does the complexity extend into the third dimension?
Dale
Many years ago I played with an inexpensive version designed to carry a Dremel tool. My task was to turn out a handful of award plaques for my son's Scout troop. It took a fair amount of practice to develop a usable process and get the "feel" of the tool. I produced almost as much scrap as usable product but eventually finished the job.
Is your "complex shape" essentially a 2-dimensional outline - that might be followed by something like a "pin router" - or does the complexity extend into the third dimension?
Dale
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Could your "perfect part" be used to create a mold, from which you would manufacture copies using fiberglass, casting resin, etc?
Dale
Dale
I don't know anything about milling machines and their speeds but if you are thinking of making a template anyway could you not just clamp it ( double sided tape?) to your work and use one of these in the mill? My guess is the mill is way too slow to run a spiral bit through most materials but if you're just cutting plastic and use a light touch it might work. It's the sort of thing I would try - though I should admit that most of what I know I learned by making lots of mistakes 😉
These are both excellent ideas!
@sofaspud & @dchisholm As for the pantograph, now that I think of it my Dad used to use one of those and even showed me how it worked. Good example why kids should pay better attention when Dad it trying to teach you something! And mounting / suspending a dremel tool would take some planning, but definitly easier then moving a whole small work table.
@Hearinspace - That router bit with the little probe end looks like a good idea too. I'm new to milling and routers so I never knew such a bit existed. And I certainly could take the time to make a template out of sheet metal.
I will agree... it will be more trouble than its worth for a few pieces, and sometimes building a tool ends up being a lot of work for substandard results, because there is merit to the argument that good tools should be build with precision parts made in a factory. But this situation has come up a few times now, and might be worth a reasonable effort. I have some things in the works for which I've been making all kinds of jigs along the way, even though I only be making a handful to make prototypes. My reasoning is that if one of these brainstorms of mine turns out to be salable, I'm going to have to make many more before I get to the quantities that make it worthwhile to have things done for me in masse.
Thanks folks! Seems I always walk away from this forum with solutions and good ideas!
@sofaspud & @dchisholm As for the pantograph, now that I think of it my Dad used to use one of those and even showed me how it worked. Good example why kids should pay better attention when Dad it trying to teach you something! And mounting / suspending a dremel tool would take some planning, but definitly easier then moving a whole small work table.
@Hearinspace - That router bit with the little probe end looks like a good idea too. I'm new to milling and routers so I never knew such a bit existed. And I certainly could take the time to make a template out of sheet metal.
I will agree... it will be more trouble than its worth for a few pieces, and sometimes building a tool ends up being a lot of work for substandard results, because there is merit to the argument that good tools should be build with precision parts made in a factory. But this situation has come up a few times now, and might be worth a reasonable effort. I have some things in the works for which I've been making all kinds of jigs along the way, even though I only be making a handful to make prototypes. My reasoning is that if one of these brainstorms of mine turns out to be salable, I'm going to have to make many more before I get to the quantities that make it worthwhile to have things done for me in masse.
Thanks folks! Seems I always walk away from this forum with solutions and good ideas!
Instead of moving the pointer & cutting tool, it may be easier to fix them into position and move the template & work underneath, clamped to a common flat surface.
I used spiral bits and a steel template to make a few hundred patterns in thin plywood, using a roto-zip. Worked great/
That's the basic operating concept for a "pin router". In some versions the guide pin is mounted on an overhead arm and the router is mounted under a table beneath the pin; in other designs, the pin is fixed in the tabletop and the router is mounted on an arm above the table.
Here's one example, sold as an add-on accessory for a standard router table: http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/daisypin.html
(You DO have a router or two, and a router table, don't you? If not, why are you reading this Forum instead of building a router table??!! )
Old age and treachery trumps youth and enthusiasm.
A generation goes, and a generation comes, but the earth remains forever.
. . . .
What has been is what will be, and what has been done is what will be done, and there is nothing new under the sun.
- "The Preacher", c.a. 10th century BC
. . . .
What has been is what will be, and what has been done is what will be done, and there is nothing new under the sun.
- "The Preacher", c.a. 10th century BC
This photo is similar to the Dremel jig I used a couple decades ago. Its most fundamental shortcoming is a general lack of rigidity, even when used with a small Dremel tool.
http://images.amazon.com/images/P/B0000719WL.01.LZZZZZZZ.jpg
Those ball bearing-piloted router bits are a mainstay item among hobby woodworkers. I think mounting a ball bearing on a router bit like that is one of the best ideas since sex in the morning (and my wife is a fantastic lover!). A hobby woodworker who doesn't own at least one would be like a DIY electronics hobbyist who doesn't own a multimeter. I probably have about a dozen router bits of that basic style - different cutting diameters; different lengths; spiral or straight cutting flutes; sharp ones I loan to my kids and dull ones I loan to the neighbors; etc.
Of course the bit can't follow any INTERNAL curves with a radius tighter than the radius of the bearing. By far the most common bearing (and cutting) diameter is 1/2". Diameters from 1/4" to 1" are fairly easy to get.
If the bearing is mounted on the free end of the bit (as shown in the link) it's almost always called a "flush trim" bit. If the bearing is mounted on the shank end of the bit it's often called a "pattern" or "pattern follower" bit - though other names, like "inverted flush trim" bit, are also used.
Sometimes you'll (unfortunately!) encounter the terms "top bearing" or "bottom bearing" in reference to these bits. My routers spend around 1/3 to 1/2 of their life on the bench with the motor above the bit, and 1/2 to 2/3 of the time hanging "upside down" under a router table. Since they often change positions, any references to "top" and "bottom" are easily confused.
By changing the bearing to a different size - either larger, or smaller, than the bit's cutting diameter - you can cut edges that are a given size larger or smaller than the pattern or template you're working from. This is also an easy way to create a stepped-edge cutout for mounting a loudspeaker in a cabinet.
Whether it's here or elsewhere, pass along what you've learned.
Dale
Dale,
in the past, for my simple rectangular cutouts, I've been using some 2.00mm Two Flute carbide end mills, and also some 1.60mm Carbide router bits, in that "poor man's" milling machine I described (just a drill press with an X/Y adjustable vise). The small bits work well for me because I'm often cutting openings for small (15mm) rocker switches with very little lip, and so I need my corners to have as small a radius as possible.
Now for this type of bit (the bearing bits you described), you mentioned 1/4" as a popular cutting radius. I guess it makes sense that something with a moving bearing wheel mechanism might be tough to make in the kind of small sizes I've been used to, Is that correct?
in the past, for my simple rectangular cutouts, I've been using some 2.00mm Two Flute carbide end mills, and also some 1.60mm Carbide router bits, in that "poor man's" milling machine I described (just a drill press with an X/Y adjustable vise). The small bits work well for me because I'm often cutting openings for small (15mm) rocker switches with very little lip, and so I need my corners to have as small a radius as possible.
Now for this type of bit (the bearing bits you described), you mentioned 1/4" as a popular cutting radius. I guess it makes sense that something with a moving bearing wheel mechanism might be tough to make in the kind of small sizes I've been used to, Is that correct?
I've done that on the drill press, with either a router bit, or a genuine 1/2" end mill in the chuck. Had moderate success with acrylic, polycarbonate, and wood but it's difficult to get things rigid enough for anything more than a skim cut on aluminum. Never tried those miniature milling cutters.
I don't claim to know much about bearings. My flush trim router bits have 3/8", 1/2" and 3/4" cutting diameters. The axial force on those bearings should be nonexistent, and the radial force is light to moderate, but a typical router spindle spins at 10,000 to 20,000 RPM so the bearings should be designed with high-speed operation in mind. I don't know if that's a limiting factor for small size bearings, or if it's the problem of mounting the bearing. A bearing with 1/4" OD will have an ID of 1/8" or less, which isn't a very substantial axle running through the bearing.
Dale
Well from what I'm seeing, I'm not going to find a pin-bearing bit like that with a bearing diameter less than 1/4". A 1/8" radius isn't bad I guess, and then there's the fact that these bits are very expensive bits. Remeber how I preface all my tool constructions with phrases like "poor man's..." (fill in the blank... milling machine, vacuum former, on and on).
I think I still wouldn't mind experimenting with the pantograph idea though. The milling bits are cheap and seem to cut polystyrene plastic really well. The one thing I'm not sure of is how I would make a pantograph that replicated the work the same size as the original. This is the best I can come up with. This picture is just a piece of a coat rack from a flea market to help me wrap my head around the idea. With the fixed pivot in the center, and template and workpieces at each end like this, it should give me an exact 1:1 copy, right? It will be upside down, but I guess I could live with that. Can you think of a different configuration that would give me 1:1 without reversing?
I can certainly identify with building your own jigs, fixtures and tools in an attempt to save a little money. $13/hr doesn't go very far, and certainly doesn't leave a budget item for "Hobbies". Sometimes I'm moderately successful; sometimes i manage to get-by; and sometimes I feed the scrap bin.
I'm familiar with those cap racks - at one point I think there were 3 of them in our house. Being mass-produced on production machinery, the pivot points are well-aligned and smooth-operating. I suspect it won't be as effective as you hope for - you'll wind up doing a lot of cleanup and trimming with files, X-Acto knives, etc. Like the version I used for a while, I'm afraid this won't be rigid enough to smoothly and accurately copy the pattern's shape to your workpiece.
The low-cost commercial products start at under $100. I'd look for some of these on Craigslist, E-Bay, or local yard and estate sales:
http://www.woodcraft.com/Product/149940/Milescraft-Router-3D-Pantograph.aspx
http://www.ebay.com/itm/like/331536988092
There is no shortage of DIY examples, where the craftsman has obviously put some thought, experimentation, and effort into improving a very basic design. Yeah, a few of these are rather elaborate and complex projects in their own right but several are quite simple and straightforward:
http://www.instructables.com/id/3D-Pantograph/step9/Placing-the-Roatary-Tool/
http://lumberjocks.com/topics/52770
http://woodgears.ca/pantograph/
http://realrecycling.blogspot.co.nz/
Dale
I'm familiar with those cap racks - at one point I think there were 3 of them in our house. Being mass-produced on production machinery, the pivot points are well-aligned and smooth-operating. I suspect it won't be as effective as you hope for - you'll wind up doing a lot of cleanup and trimming with files, X-Acto knives, etc. Like the version I used for a while, I'm afraid this won't be rigid enough to smoothly and accurately copy the pattern's shape to your workpiece.
The low-cost commercial products start at under $100. I'd look for some of these on Craigslist, E-Bay, or local yard and estate sales:
http://www.woodcraft.com/Product/149940/Milescraft-Router-3D-Pantograph.aspx
http://www.ebay.com/itm/like/331536988092
There is no shortage of DIY examples, where the craftsman has obviously put some thought, experimentation, and effort into improving a very basic design. Yeah, a few of these are rather elaborate and complex projects in their own right but several are quite simple and straightforward:
http://www.instructables.com/id/3D-Pantograph/step9/Placing-the-Roatary-Tool/
http://lumberjocks.com/topics/52770
http://woodgears.ca/pantograph/
http://realrecycling.blogspot.co.nz/
Dale
Oh gee! Thanks for all the links Dale. But just so you know, I was NOT intending to actually use that coat rack. I know that's too flimsy. I was just using it as a mock up model to confirm my logic, that this arrangement would produce a 1:1 copy. I didn't care for the fact that it would make an upside down copy, but such an arrangement would provide extra stability, I figured, since each key point would have the benefit of two braces.
Obviously to make it workable, I'll have to use some heftier wood, or maybe "U" channel aluminum, get 7 bearings, and make some creative clamps for a pin guide and either the dremel or a small work table to use with a drill press. I think everyone convinced me the dremel was the better way, so probably the thing that will require the clamp to hold the dremel will require the most attention.
Anyway, thanks again for all the links. I'll look at them all now!
Obviously to make it workable, I'll have to use some heftier wood, or maybe "U" channel aluminum, get 7 bearings, and make some creative clamps for a pin guide and either the dremel or a small work table to use with a drill press. I think everyone convinced me the dremel was the better way, so probably the thing that will require the clamp to hold the dremel will require the most attention.
Anyway, thanks again for all the links. I'll look at them all now!
I was quite surprised by the large number of DIY projects that turned up when I seeded a search engine with "pantograph dremel" or "pantograph router". I recall seeing a couple of write-ups over the last 40 years or so, but many more people have put some thought and effort into this basic concept than I would have guessed. At least skim a handful of the writeups, glean the best (or at least most practical) ideas and create a tool especially for your needs!
Dale
Dale
Geez, as I was reading through all the posts, I couldn't wait to get to the end and tell you guys that the diy pantograph for tools is actually quite easy.
And then I get to the end.
Thanks a lot Dale. 😀
And then I get to the end.
Thanks a lot Dale. 😀
Well hey Cal, I haven't actually built it yet, so I'll take any tips you might have. I'll likely be using a dremil with a milling bit when I do build it, so any tips on mounting are helpful. I'm also curious if there is another configuration for making 1:1 copies, that don't result in the cutting side being upside down. I realize its not really mirrored, but it seems it will be confusing.
I couldn't begin to describe more easily than watching the vids on you tube.
https://www.youtube.com/results?search_query=pantograph+dremel
https://www.youtube.com/results?search_query=pantograph+dremel
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