Very impressive machine. I enjoy seeing the various tools and equipment people build and have personally gone through phases where the tool building itself became more of a focus than the end product. I'd like to attempt something like this one day though I don't do much spindle work…perhaps instead some form of poor man's ornamental lathe. My favorite part is your use of the nordic track.
Thanks, all, for your great comments! Michelle, I thought you were just being friendly.. until I looked at your projects…WOW!! Now I'm wondering what your method is for your unique turnings!
Yes, Richard, I'm too cheap to throw stuff away, and it all gets used on some contraption or another. Padre, thanks again for another heart-felt compliment!
Actually, the reason for making such a device was explained in one of my earliest threads as an LJ. I was commenting on my worst woodworking experience, in which my work was featured in an upscale gallery, only to have my successful designs duplicated by others. Though the thread morphed out of control, I resolved myself to only do work that could not be easily duplicated. Though a few took offense to that statement, ultimately if I was doing rope-turns, spiral flutes and barley twists instead of standard joinery stuff, I might have persevered in that craft boutique. But that was long ago. Now that I'm entering my twilight years, I might do a few crafty things and/or donate to fundraising activities in the future. Though I still like to test my limits, whether woodworking or creating machinery and fixtures.
Heh, yes Topamax they sure did…but if I recall, they had some sort of yo-yo string design to move the fixture along the workpiece, which did not have the accuracy of this device. Don't confuse what I said about unique craft designs with fixture designs! Of course there are lots of spiral machinery configurations around. Mine more closely resembles the "Legacy" mill, only with a link drive instead of a lead screw. Actually, mechanical fixturing dates back to the 1800's, not to mention every screw-cutting lathe in the world…. Mine can do spirals in 2 directions with a 2-minute change in the set-up. Nothing drives me nuts more than spiral legs or bedposts that all spin in the same direction!!!!!! It's like the work of the devil or something….
Any comparison with a Router Crafter is an insult (other than the intended results). I picked one of those up at a garage sale several years ago and then sold it at my garage sale 'cause I never could get the thing to work right! Cheap, flimsy, poorly designed… but I digress.
I would love to see more details and perhaps a blog that describes the operation more. This is something I could envision building for myself.
Thanks, EE andWoodwrecker!
I could probably put together a list of materials and some set-up instructions. I'd probably go with recirculating ball-bearings when I make the permanent keeper version. So far, between scrounging and some eBay and local hardware pieces, I've kept the cost down to $200 or so, the only single big expense was the 1:1 angle drive gearbox which was $50 plus shipping. I made my own headstock but perhaps if you have access to an old lathe you might be able to upfit it in its entirety. If I had a trove of spur gears, I'd make a leadscrew version instead of chain-operated indexing. It was important for me to meld old and new, but…picking up piece-parts and starting all fresh is really the path of least resistance, and it would still cost less than $500 or so. I'd be happy to help anyone deciding to make one of these. It's gonna be fun using this new toy!!!
Thanks all once again for your kind words!
don,...yeah, I came so close to simply sending a check to Legacy for one of their really excellent mills….but I was afraid once the novelty wore off it would become a $2300 clothes rack. By the way, are you using those bird's mouth shaper cutters to make your hollow columns? If so, how do you find your centers?
I'm amused by the fact that now that I've built it, I actually have to gather some notes together to remind me how to set it up. Heh, looks like I need to write an owner's manual, LOL! I've got quite a variety of gear ratios available for experimenting with pitch angle, etc. Everything is on shafts and set screws, so much that can go wrong if I'm not diligent about making sure everything is buttoned down before I switch on the router…but I'm really going to have some fun with this! And, as I said, I'll help anyone who thinks they'd like to make a similar unit.
Good for you PKat. That is quite that machine. You do some good scrounging. This really reminds me of homebuilt CNC. They are so cool, but it is a very scary and a unique thrill when you turn on the router and let 'er rip.
I have lots of questions:
Do you think you might get less backlash with toothed belts instead of chains? I have never really thought of chains for linear movement control.
How is that Nordic linear bearing setup working? Can it hold up to the sawdust? Is it 'tight' and can the router lift up? It is hard to tell from the pictures.
Is the chain drive hand driven? Do you think you could hook up a motor drive (or maybe even a variable speed drill) to drive it?
Thanks, Don! Spalm: Yes, backlash was a bit of a problem, and what you are seeing is my very first cuts…I forgot to tension the linear-drive chain. That chain was old and sloppy, darn it! But it is only the equivalent of #25 bike chain, which is 1/2" centers X 1/8" wide. Yeah, that 'double-cut' was from reversing the stroke, it was off by perhaps 2 degrees…from the slack in the chain. I first got the idea from an overhead door opener. Now I know… do not cut on the return stroke… unless the chain is TIGHT. My mistake, but not bad for a first cut!. Yes, I also used #35 chain for the loop between the spindle/headstock to the angle drive. I have 5 sprockets ranging from 22 tooth to 84 tooth, so I'll get a good variety of pitches. Yes, I'll need to cobble some lengths of chain together for the various theoretical pitch diameter combinations. Right now, the linear travel is 7 1/2 inches with a 28 tooth sprocket driven by a 36 tooth, with a linear sprocket pitch diameter of 2". (Like overdrive) Every rotation of the 2" linear drive sprocket = 2Pi of travel. With the right ratios, you can have a gentle twist on your workpiece, or a fine screw thread effect, or anything in between. Remember that the exercise equipment was meant for somebody to be standing on those trolleys, the weight of the router is negligible. One sheet of 3/16 polycarbonate took all the slop out of it, when screwed to the 4 corners of the trolleys. Remember, I intend to upgrade to linear ball bushings on the final version, with hollow-ground 3/4 " shafts, but this nordik thingie works quite well. I'll probably need to keep an air hose nozzle handy, but I don't expect dust problems. I was looking at router lifters, there was a good thread here about these recently, but I elected to simply use my old plunge router in this prototype. That big 6" v-belt pulley was put into use as a hand wheel, with a spinner knob on it, not visible in the pics. It will only be at most maybe 12 rotations for the total travel unless you're doing very fine threads. There is no more resistance felt on this handwheel than rotating, say, a pedal of a bike with the wheel up off the ground. I'd like to get foot switch control for power feed, and lifting the router as time goes by. I need a bit more choices for flanges/face plates. No chuck is necessary, my headstock spindle is 1/2" and I counterbore a 1/2" hole in the workpiece about 3/8" deep to accept the end of the headstock. only one screw through the flanged faceplate keeps it perfectly aligned and indexed. There is a lexan index plate too, by the way, so it is easy to space your entry cuts around the circumference of your workpiece. Some of my inspiration comes from You-Tube videos, do a search for "barley twist Lathe" and visualize a unit substituting your hands and mind instead of expensive CNC .
I enjoy reading about your build. You must have some background in working with things that are mechanical.
I spent most of my adult life, almost 60 years, working with mechanical and electrical things.
One of the things I learned is that when you take all the slack out of a gear or chain drive, really take the clearances to zero, binding occurs. No gear or sprocket is perfectly round, no bearing tracks perfectly and no sliding track is perfectly linear. Its possible to get the clearances worked out to zero at one point yet have the mechanism lock up at another point. adjusting to zero at the bind means that the mechanism will have "slop" at other places.
Practicality demands that we get it running as smoothly as possible and then always remember the "slop". That's why the Legacy manual says to never cut on the back stroke. There is "slop" and they deliberately don't attempt to engineer it out. It causes too much trouble.
Could they get it closer?
Sure, but then the costs would escalate.
I'm happy to deal with it this way because I don't want to pay even more for it.
Having said all that, I have to point out that I sometimes do cut on the backstroke anyway. It can result in an artistic effect.
Thanks. Lots of options. Having worked on this kind of problem with a homebrew budget, I feel like I can relate to the kind of problems and solutions that must be racing around in your head. It can be all consuming and fun at the same time.
I remember that you were looking at McMaster for parts, and having shipping problems. Have you tried VXB? They are a cheaper place to get (imported) linear parts, should you want to. http://www.vxb.com/page/bearings/CTGY/LM