A Modern Jensen 10?

Mister Occlusion · A Modern Jensen 10?

This has been on my mind for awhile now.

I know there are stories out there about Jensen having looked in to the possibility of reintroducing the model 10 in the past, having used an old one as a test bed and mounting a new generator. I know this idea was rejected, though I do not know why. Difficulty of production? An inability to burden the production line with yet another cast base? Economics? Or perhaps a combination of all of the above.

So, I was thinking: Would it be possible, with off the shelf Jensen products and a bit of creativity, to recreate the essence of the old direct drive Model 10? Surely all it would need would be a good eyeball to align the generator and engine shafts, and a workable flexible coupling of sorts to accommodate changes in shaft alignment due to my not having the luxury of a single monolithic iron base.

I set to work brainstorming a coupling. It had to be something that was close to hand. I thought about springs - a bit off a tubing bender might work, had I one. I thought about rubber hose - how to clamp it neatly, and how long a life would it have? I thought about universal joints, and briefly entertained building one to the point of having worked up a practical design for the semi-skilled drill press operator, when it occured to me that I would need *2* U-joints in order to accommodate lateral movement in the assembly.
Sadly I discarded this idea as being just beyond my skill level. I have a hard enough time drilling a straight hole through the side of a brass tube. Let alone drilling several such holes neatly enough to tap for the screws that I had planned to use as pins.

Finally, inspired by something found in a bin at the hobby shop, I came up with a semi-universal joint. Fundamentally it's a universal with the 2 sets of pins separated by a shaft. The shaft has an oversized hold drilled in it for the pins, which allows for lateral movement in all directions (though not as smoothly as a true universal would be).

It's crude, but it was possible.

I set to work making the bushings that would bolt to the generator and engine shaft. I laminated 7 sections of K&S brass tubing for this. In retrospect that was probably at least 2 too many, but I was unsure about the stresses this would be subject to, so I overbuilt.

The first two sections were cut the same length as the end of the engine/generator shafts, and the remaining 5 cut longer. My steel connecting rod is the same diameter as Jensen shafts, so I reasoned that by stepping up 2 sizes like this I would have sufficient wobble room inside the bushings for the shaft to move laterally in all directions. there isn't a LOT of play, but there is enough to deal with any possible warping that the wood base might undergo.

I used the K&S tubing, because there is no way in hell that I would be able to bore a straight hole into brass rod with my drill press. It's simply not going to happen. If I had a lathe and knew how to use on it would have been a simple matter to do in a few minutes what took me over an hour to do per bushing.

Anyway. Sanded and cleaned the tubing inside and out, slapping piles of flux in each layer. Gently heated the whole lot with a torch (being careful not to get too hot and soften the brass), and the solder flowed into it just dandy.

Some carefull drilling for the grub screws and pins, and tapping the first threads I have cut in almost 20 years, and I felt pretty bloody clever.

The connecting shaft gave the most trouble. I was just going to cut a channel into each end, 90 degrees apart, and fit them into each pin like that, but I could not get the slot wide enough without spending hours wearing away at it with garnet paper (I'm impatient). In the end I drilled a hole through the side at each end, as large as I dared, and thus it became permanently bolted to each bushing.

I packed the interior of the bushings with a heavy bullet lube, in order to cushion the action of the steel rod on the fine brass pin screws. This lasted all of 2 minutes once under steam.

But it DOES work.

Vibration is there, however slight. First a set of grub screws came loose. Later the big flywheel came loose and wobbled back and forth on the shaft (that was interesting).

The universal joint that I made works, but on this level it's far too clunky and crude. I ordered some K&S tubing benders off ebay. If one is the right size for the Jensen shaft I'm going to try a section of that for a coupling. I just need to work out a way to clamp it to the shaft without it coming undone one way or the other...

I'm going to post this now, so I don't lose the text if the browser crashes. I will come back in a followup post immediately below this with picture and video links as soon as they are ready

Mister Occlusion

Just waiting for the videos to process.. Those links will be at the end of this...

Here's a completed bushing resting on bits of the second one

Here's the same bushing resting with ALL of the tubing sections that were laminated together to build it

Here is half of the semi-universal, mounted to the model 15, with coupling shaft in place.

The completed joint. Black washer grease caps (more for looks than function I guess). Note yellow grease. This is all natural Thompson Center "Bore Butter" of the stiff sort that you would load into a bullet lubricator machine. I was going to use bearing grease, but decided I wanted something stiffer and less messy.

Completed... Good photo for entry in the Feb EotM?

Another shot. I was very lucky that I had a perfect sized bit of hobby plywood to mount the generator on to that raised it into perfect (visually) alignment with the engine. I was prepared to shim under its feet with washers had it not worked out

Under steam, flash photography making it look still, save for the light bulb

A better action shot

http://www.youtube.com/watch?v=7nnCBBk_-_I
First video. Construction overview and the first run. Piles of commentary (unfortunately

)

http://www.youtube.com/watch?v=KPczof6q0ao
Second video. Running without commentary.

I'm certain that the coupling could be perfected to the point where this becomes a completely viable configuration. I would like to have a 15BL generator for it, so that I could have a PTO pulley, still, instead of losing all but the inboard engine one.

So with a little time and effort you too can have a "model 10" on a model 25G budget

Cedge

Mark...
Tis a thing of beauty you've created. It completely captures the essence of the old model 10 experience with a nice flair. Success does have the sweetest of smells... eh?

Steve

steamyjim

Well done MR O. Its a beuty!

Sandman

Great work Mr O.

Griffin

Nice one Mark, a creative rendition of an old #10 there.

I like the way you have thought the layout through, very effective.

Well done.

Mamodman123

Brilliant, just outstanding

TRAPPERKEEPER

Nice! That is my favorite creation of yours yet

johnreid

Real Good, I think you are on to something good there.
The grub screws might dig in better if you used a regular set screw that has a point to dig into the shaft, usually tightened with a hex key or Allen Wrench as I call it.

I doesnt seem to add any more load than when driving with a belt, or does it?

IndianaRog

Mark, what can I say...that is exceptionally creative and the finished result looks...well, like a finished result!!! It is obvious you planned it out and it shows, really, really nice. Don't know why I never tried that myself!!! Mr. J would have been impressed.

cheer's
Rog

Reid

Creative and well done, Mark.

Direct drive is the best and proper way to drive a dynamo.

Damn, you do neat work!

---

One of the great complaints of the old line shafting system was the huge, huge, loss of power to belting and bearings.

Even our toy belts are inefficient: all that stretching of elastic steel,
that is a conversion of motion into heat loss of the engine's small power,
and the friction of the belt laying into the pulley groove (including the natural wedging effect into the pulley knurlings.

Also: no more side-thrust on the engine nor generator bearings;
more power saved there and less wear.

Yes, direct drive, for something as hungry as a generator, really pays in transmission-loss savings.
The only downside is the necessary speeding of the motor in result.

Mister Occlusion

That's some good insight, Reid. I know I had resisted using lineshafts for the power loss they incur, and I know, empirically, that spring belts and rubber bands also exact their price in power loss, but I had not considered the consequences for the engine and generator bearings

I suppose that even if you used a gear system to change ratios you would still suffer the same penalties.

It's funny, how today I was musing about your early electric motor.

We had steam engines powering singular machines directly, and then powering many machines remotely through manual transmission of kinetic energy. We still have that situation today, save that the steam engines are far away and kinetic energy is converted to, and then back from electrical energy as a means to do away with the shafting.

Everything modular with its own engine, and yet fundamentally connected through the "lineshaft" known as a power grid, or bus.

It's nothing new, I know, but it's the first time that I truly opened my eyes and saw things that way.

It's so easy to take things for granted; "the wonders of science and modern technology" is a comfy blanket term used to describe just about anything. It's grand indeed, but fundamentally evolutionary rather than revolutionary. And in the unerpinnings of it all, power and motive force still comes to people in much the same principal way that it has done since the beginning: transmitted from a primary engine.

~~~~~~~~~~~~~~

To everyone else: thanks.

I was thinking that this would be the poor brother to my model 20 somethingorother, since I could not put this together the way that I had originally imagined. As intended there would have been room for a second boiler on that base (dead serious here

).

But, after the first run, I can see plainly that as it sits as a model, it in no way needs more steam. At this point all I am going to do is either refine this coupling, following the suggestions re proper set screws mentioned above, and rechecking for alignment problems after the wood has had time to settle, and just enjoy it for what it is: something familiar, but just a little bit different

I have generator tests to run with the 20 too

John.... I can't really comment as to loading. I don't recall if I ran the 15 from the 25 before, which means that if I did I sure don't remember how well it worked

But, again, empirical evidence (and Reid's dissertation) suggest it being a more efficient mechanism.

Still too early to tell. I have vibration to fight, and a coupler to refine before I'll have any right to make a real world comparison.

We're still in alpha testing here

Well...maybe I can say beta, since the wood has been stained and finished

Maybe I'll try to direct drive a stepper from a model 70 next...

IndianaRog

Mr. O...check out the generator to generator coupling I made up for my Jensen 51 replica...it consists of two Jensen pulleys (a 1 step and a 2 step) bonded together with silicone bathtub caulk. This allowed me to use the shank and grub screw from each pulley to snug up and align the shaft of each AC generator...effectively making them perform as one...pulley hole and shank are by design a perfect fit. Two belts come off the main flywheel to the two larger pulley steps and a stepper DC generator below is lashed to the center of the 3 pulley steps...so there is a lot of force on that joint!! Although silicone is the only thing holding the pulleys and shafts together, it has never come undone in 70 hours of operation.

I smeared on the silicone to the pulley faces first, tightened the grub screws second, used small blocks of wood and several C clamps to press the pulleys together tightly overnite. Lastly I added a drop of Loctite to each pre-cleaned grubscrew and let a bit penetrate the shaft holes to give added grip on the shafts. .

IF you did something like I did on your modern Jensen 10...you would have pulleys for power take-off as well

cheers,
Rog

Mister Occlusion

I thought long and hard about doing it your way too, Rog (shamelessly explored all options, including the sincerest form of flattery

).

In the end, though, it would have still left me with the requirement of having and maintaining perfect alignment between the 2 shafts, which isn't something that I could be certain of.

Maybe I'm over thinking and over building it? It's quite possible. A solid connection has worked for you, after all. But I'm also not sure how much misalignment there could be induced in that 70+ pound monster of yours, since I don't expect that it changes location much

I also know nothing about the behaviour of finished wood, whether it should have been left to acclimate for a few weeks before finishing, how much I can expect it to distort, etc..

I'm building to best allow for the variable of my own inexperience

I had thought of mounting engine and generator on a stout bit of steel, aluminum, or even brass sheeting in order to give stiffness to the assemblies. I dismissed that as being impractical, since no one locally would have large enough sheets, and it would hide a lot of the wood. Also thought of a framework of some sort, possibly using band or angle irons of appropriate size, but there we're getting complicated again and I'm a pretty simple (crude) fellow when it comes to fabrications. I use a ruler, square, and tape measure, not vernier calipers

That might still be the path to a practical solution, though. If I can't have a monolithic framework like the original 10, then a rigid built-up one would be the next best thing.

....or I could just build/find a better flexible/universal coupling

Had briefly, VERY briefly, toyed with the idea of building a single shaft for both engine and generator, but:
A) I don't know how to take apart and put back together a crank shaft, and doubt my tools/skills would let me do a proper job of it
B) I don't know how to take apart a model 15's armature from its shaft, or know if it's even possible and I'm certainly not going to bugger up a $100 piece of kit just for the sake of satisfying curiosity

C) would still need careful shimming and attention over time in the short term at least to maintain optimal alignment.
D) Deviates from the purpose: To build up something model 10-ish from off the shelf parts, a bit of creativity, and minimal fuss

I'll locate some proper set screws next. Failing that I will grind these ones down to size and make points on them for a short term solution. Also need something better to pack the bushings with that will cushion without hindering motion.... silly putty maybe?

johnreid

Proper set screws are made of a harder material, sharpening the tips of regular screws will result in a softer and more likely to be problematic screw tip, the voice of experience is speaking here.

IndianaRog

Mark, you might look into flexible couplings/U joints of the kind used to transfer power from engine to prop shaft in a model boat. I know Moose used something very secure yet flexible on his Hobbies Arrow boat build last year, he could tell you where he got the coupling.

Mister Occlusion

I saw small parts source had some flex couplings, but they were only rateed for a few hundred RPM. I think that for safety sake I would need one good to the 3000 RPM that a free wheeling 25 is capable of. No idea what this one is hitting, but I am guessing it's kicking out somewhere in the neighborhood of 2000.

John: yeah, it occured to me during this morning's ablutions that a mild steel screw would probably not work if made pointy.. mainly because I remember the big old Jensen grub screws in my older flywheels were flat bottomed. To stick with those I would have to grind a flat on to the shafts, I expect. Far better to do as suggested and locate the correct parts

In retrospect it is probably a good thing this one wears a model 55 flywheel. I am thinking it would run rather rougher with the light alloy one. I briefly toyed with the notion of the 4-inch flywheel, but I really don't want to have to dig out the old wood gouges

The thick and heavy 3-inch 55 wheel has a nice visual symmetry with the thick and heavy generator magnets too.

Mister Occlusion

Found the set screws tonight, about 10 feet away from where I was pouring over screws the other day.

Only issue is they only had down to 6x32 and I had tapped these 4x40. So I bought another tap and will have to redo the holes.

I used to think threads were confusing. Now I see there is a standard selection of sizes that meet most needs.

....other than that oddball one Jensen uses for SV/whistle threads... Megalomart didn't have THAT one

This all dovetails nicely into my longer term project to build a proper oiler. Now I can make and thread my own pipework instead of laminating nuts together

Slowly but surely goes the learning process.

johnreid

Do you buy Propane and Propane accessories at Megalomart?

You might want to buy some bottoming taps as they are not as tapered as the ones at Megalomart. I have seen sets of taps go for a reasonable price if you are stocking your tool chest.

Mister Occlusion

These are plug taps I have, which I gather is a compromise between bottom cutting ability and ease of starting.

I don't foresee having to cut any blind threads... But then I didn't foresee ever needing to cut threads in the first place.

The propane accessory selection kinda sucks too

They only had 1 MPS compatible torch head, and it's got that whirly flameholder in it that I really don't care for. But I'll try it anyway.

I'm trying to not go crazy on tools. Pick up what I need when I need it, sort of thing.

But what I think I DO need is a proper vice for the drill press which adjusts in 2 directions while bolted to the platform. the one I have now is a glorified clamp and it makes drilling holes in a straight line impossible.

The nice ones come on sale every few months. I didn't get one the last time (dithered over it). I'll for sure pick one up the next time.

Anyone got any tips for combatting the annoying tendency of drills to skip all over the place when starting out? Centre punches help, but sometimes do their own damage...

Also, when I cut brass with a large bit, say 1/2 inch or bigger, it always starts to... I don't know what, but I end up with a roughly elliptical hole after it has chattered its way through it. I've started using some 3-in-1 oil on the work while cutting through brass, but it only helps a little for large holes.

Wallace

Cedge

Mark
Drilling is something most people "think" they can do. There are tricks to it though.

#1 get a set of center drills. They are specifically for preventing drill wander. These are short very stiff bits with a small drill point and a tapered cutter that drill a lead hole and a drill guide hole. Once the lead hole is there the drill bits will not wander and they follow the lead hole. It makes for much straighter holes.

#2... after the center drilled lead hole is there, begin with a small drill bit and then work your way up the just below the desired finished hole size. Then you can either use a reamer of the desired size or a drill bit. The last cut will only need to shave the sides, making the chatter problem far less likely and a clean hole much more so. For a half inch hole I'd typically begin with a center small drill, then a 1/4 bit, then 5/16, then 3/8, 7/16 and then ream it or finish drill.

Use cutting oil or tapping fluid to keep things slick and you'll do fine.

Steve

johnreid

Use of a Center Punch is advised too.

Mister Occlusion

Figures that I'd never heard of center drills.... I *had* wondered if there were shorter bits out there, at least for the small sizes. Those will help immeasurably.

The problem I have with center punches is that they themselves tend to be hard to center, being so large in diameter at the head. I need a smaller one, apparently... Stuff to add to the shopping list.

I did discover early on the wonders of reamers and have a few. An old long slim one, and a new one that tapers up to an inch. I even use a specialty one made for cartridge cases if I just need to clean up and put a slight bevel on a hole: very useful for the K&S tubes above, say .22 calibre or so

Cedge

Mark
Try www.Micromark.com and check out item numbers 31114 and 82281. Both are like having an extra hand. You'll spend hours on this site and be sure to request their catalog. The come often and always have something new and ingenious for the model engineer,

Also visit www.littlemachineshop.com and wander around a bit.

Both places have hard to find model building tools as well as lots of tooling for home machinists. I've used both for purchases and have enjoyed excellent customer service from each company. You can often compare prices on items between the two to make your best purchase.

Steve

Mister Occlusion

That 82281 will be absolutely Invaluable for sure.

Got to get a 2-way adjustable vice for the drill press too. I remember those from shops class as being handy as hell.

Thanks!

I ordered a double universal joint last night, and paid extra for 2-day shipping. If it's not here by Monday I will be especially unamused.

I think I'm going to slap a coat of varnish on a bit of old particle board from a sink cutout that I have and mount the whole thing on there for the coupler trials... I don't want to be drilling piles of holes in my nice board every time I have to move the generator to accommodate a new coupler... ...I should have done that from the first, I suppose

johnreid

Those Center Drills are a lot stiffer too. I wish I still had a Drill Press.
For Soldering and such I have a PanaVice, it is quite useful.

Mister Occlusion

Ours is just a small bench top drill press Canadian Tire store brand thing. The platform doesn't tilt, but is firm, so I can't complain.

More and more I am thinking of shutting down my test servers and clearing the bench space for a lathe... Uncle still offers use of his unimat. I'm sure it can't be difficult to figure out the basics: making something round and drilling out properly centred holes in things

And then I can start hanging out at scrap yards too

Time to muck out again: make some space.