Hi Brad,

I'm with you on designing and building a prototype new boring machine. I think that Tim has already overcome the gear supply problem using Toyota Tercal standard drive shaft parts and has even made up a new angle iron and flat bar prototype. The next hardest problem to overcome is obtaining new 2" and smaller drill bits.

I would love to 3D model one of these machines.

Regards

Ken Hume

http://www.utahtrikes.com/ARTICLE-33.html

I am not sure how this unit actually works but it is of interest, Schumpf High Speed Drive. It is expensive $5-600. It has three speeds. Set up a system with it as the transmission, the two final drive gears would not change.

A machine shop could make bits. With CNC technology is should not be a problem, we just have not asked in numbers. The cheap 1-1/2" bit I use is machined and it works great. It was mass produced somewhere, China probably.

One item I like on the Millers Falls machine is the round upright shafts. Even though these machine do not require exquisite machining and high technology would it be a bonus? I looked into bearings for the head, there is available a type of bearing which spirals up through the cylindric shaped bearing allowing the head to flex and not bind. I ruled these types of thing out because of longevity and simplicity. Crud will build up in the intricate parts. One of the reasons these machines are still useable is due to the simplicity of them. I would forgo this to sample the Schlumpf unit, though.

Tim

The Schlumpf is an interesting choice for internal gearing on a bike. I've looked at them for doing a 2spd with a chain and single cog on the back. I'm pretty sure they only offer 2 ratios, not 3 - so it gives you twice as many options as your current drive train - so a 9 cogged rear on a bike would yield 18 'speed' options. For a mortiser you'd have 1:1 and then lower or higher depending on what option you chose (unless you also somehow had gears right @ the bit spindle.

The Schlumpf works by hitting the center 'button' with your heel as you come round on your pedal stroke. They make a 'mountain' drive and a 'speed' drive (essentially one that works to lower your gearing (for touring) and another that would higher it for flat / road riding.

There are gear ratios and such posted here:
http://www.schlumpf.ch/sd_engl_funktion.htm
http://www.schlumpf.ch/md_engl_funktion.htm

And pics of the internals here:
http://www.schlumpf.ch/sd_engl.htm



The issue I'd see adapting this to a boring machine would be running a short chain or developing a gear cluster that turned from perpendicular to horizontal to drive the bit. Not impossible - but a typical bicycle bottom bracket (which houses the unit) is 68 or 73mm wide - so you might have to make the spindles / axles that carry the arms (or cranks, in this case) longer. The assembly would have to sit in a properly machined and threaded shell.


You could buy an adjustable one here.

Or a blank that would require fabricating / welding / brazing it to other components (maybe the internal frame that moved up and down...) here.

I see a short chain drive turning a cog on an axle that then is geared to turn a bit. You'd have to build a rigid stand for it, and work out the geometry such that with all the hardware it wasn't too tall or wide while sitting on a timber. Could be a cool project. I'm already envisioning how the drive system could work with an axle and gearing to change the direction on the bit. And then maybe have a ladder that the whole rig climbed to help pull it out of the bore hole. Machined aluminum maybe for the framework.




When I planned to cut a frame for a friend back in 2003-2004 I schemed up all sorts of bike related mortising machines and routers. Would love to have 2 setup - 1 for boring mortises, another with a 2" forstner type setup for roughing out housings... something I never investigated fully was how to get around the chain / interface part - but if Tim is gutting car parts and getting gears to work - it would seem like something that is possible...

I was more thinking about reproduction parts to refresh existing machines. Maybe improving the quality of the gears so taht they don't wear so quickly and break teeth. Given the quantities, I don't think it would be something to make money on, but to just be able to get the parts and keep these machines working. Availability of a new machine would be nice, but same problem as above. Limited run and expensive tooling to make it nice like the Boss or the MF. There is something to be said for simplicity as well. The more gear steps you have, the more your effeciency goes down too.

Well I put the Double Eagle to use this week. A fine machine from the good fellas around here.

Things I learned by boring cylinders:

Make sure your mortise has the proper length to width.

A corner chisel is a fine tool when using the boring machine. I don't have any corner chisels, but if I had some, I would have two. One that is 1/2" for the 1.5" mortise and two that is 3/4" for the two's.

Knots have to be recognized more importantly.

Fun tool, I like the chips it makes.

Used one of the spring loaded punches (?) from the big box store to guide the lead bit. Worked well.

A great machine (apple powered and all), takes longer than a Mafell, but sounds nice.

p.s. by the way, the ratio the maker made when it was produced in the 19th century was the right one. No need to alter on this end.

p.p.s Oh yea, all hail the slick!

Hi Mo,

The proper length to width, such as a 2" mortice should be even numbered in length, like 4, 6, 8, inches long. I take it that is what you mean? I like to do that with my joinery, but it does not necessarily have to be. When I use my 1-1/2" bit I leave a 1/4" or so of wood between the holes this is removed with the corner chisel, then the sides are slicked. I find if the holes are in contact with each other chips can bind in the inter-medium, a chip gets caught between the bore hole and the bit, making it more difficult to turn. This is not as much of a problem with my 2" original bits. On long mortices 12" - 24" and longer even shorter ones sometimes, I try to I try to bore as few holes as possible. I find a 1" between holes is the most I want to deal with usually 1/4"-1/2". Also on a brace mortice I do not bore the ends first, I start at the heal/butt end and work toward the the bevel. I find this will save a hole as well for you can knock a bevel on the remaining scrap.

I am doing these steps as experiments to shorten the process. I waffle back and forth on how I proceed through a mortice. I try not to get my self caught in a rut, I might miss a detail or short cut, so I mess around with patterns and such looking for a simpler process.

I do use a corner chisel to clean between holes if necessary and the ends as well. I believe the 3/4" is for the 1-1/2" mortice and the 1" is for the 2" mortice. I use just the 3/4" chisel, it will cut both easily. The 1" is too fat for the 1-1/2" mortice, it extends into the other corner. Jack Sobon does not use a corner chisel, he just drives the correct size normal chisel through both corners and with a prying action forces the crud into the mortice. Jack is a big boy, and I, not so big, I tend to lean toward removing a smaller portion with the corner chisel. On 2" mortices I drive each corner twice, I find it is less jarring on the body, all the heavy pounding. Kind of like handling boards I will go with a single board in stead of 2, more trips but I am not beat out, I am taking a comfortable load or chip for me.


Knots, you will look for better wood, which is what you should be doing anyway. A bonus for the hand cranked machines, it makes you work with the wood. I think that is why they are called "nots", not here, you don't bore.

If you find it takes longer than the Mafell, you need to crank the handles faster, or hide the extension cord.

Tim