Skipjack by michael mott - 1/8th scale - SMALL - 19 foot open launch

[michael mott]

Thanks for all the likes and nice remarks.

 

I did finish up the head today.

 

 

 

It was starting to bug me. I used needle files then 400 wet and dry 600 wet and dry 1200 wet and dry then red rouge on some swede side of a leather polishing stick.

 

Michael

[EdT]

Like a piece of jewelry, Micheal.

[Twister]

Ah, but what he hasn't told you is that he's 8'6" tall with hands the size of serving platters!!

 

In all seriousness Michael, I would never have believed such machining was possible - having recently acquired a lathe I'm having problems turning things down to 0.5mm accuracy!!

 

As usual, I'm in awe....

 

Row

[michael mott]

Ed and Row thanks for your kind comments.

 

I had a bit of fun today I had some gear-heads from some pretty old servomotors full of very tiny gears and pinions all with micro ball races. I stripped these apart to see if there was anything that I could use to fabricate the revers mechanism with.

 

With a bit of careful re-machining a couple of pinions and one of the main drive gears I think I will be able to pull this off, the progress so far.

 

 

Cheating a bit I know bit machining gears this small is pushing my limits. I knew there was a reason for saving those gearheads these last 35 years.

 

michael

[SJSoane]

 

Michael,

 

there are no words left to describe how wonderful this is....

 

Mark

[Bedford]

I'm interested in how this bit will come together.

There are some things that are worth keeping aren't there

[EdT]

If you were me, Micheal, you would probably have thrown those gears away a month or two before you needed them.

 

Ed

[popeye the sailor]

I've had moments like that........save something for so long,  then get tired of it hanging around,  and throw it away.   then to have the need appear about a month later.   truly a bummer moment

 

I notice the clearance between the two gears.......the alignment of the shafts look a bit off..    is that a camera or dry fit thing?  to shim the engine would be a hard thing to do,  but you may be able to modify the well that the opposing shaft fits into.  I hope I'm wrong......or I'm just seeing an adjustment that you know you'll have to do       very nice progress

[michael mott]

Mark, Steve, Ed, and Denis thanks for your comments, and for all the likes.

 

Denis the picture shows the few parts that I am using just placed to get a sense of if they would work. I have since been working on the design of the reverse mechanism, for reasons of scale practicality, and to maintain some sanity I am working with the two pinions and the two spur gears and drawing a gearbox that will work.

 

The entire gearbox is covered with a protective shield (no doubt to prevent feet or clothing from getting snagged) on the full sized boat. So I am working with some drawings from the day showing how these gearboxes worked, and fitting in the gears that I have to make the mechanism work. 

 

The originals used a series of clutch plates and the forward /reverse lever either caused the outer casing to be rigid hence letting the internal planetary gearing to impart a revers motion to the prop shaft, or they clamped the prop shaft and casing together causing the whole body to revolve giving a forward motion. The vertical position of the lever caused a neutral position for the prop.

 

Here is a drawing of the progress of this design so far, I have re-machined the pinions already the shafts were pretty hard and it was nerve wracking to say the least.

today I am going to make the outer casing this will be brass. this will allow the gears to seat in brass giving a quasi bearing, similar to an old clock where the gears are steel and the clock plates brass.

 

 

revers gearbox.pdf

 

As I say this is a drawing in progress and is a bit of a design build as far as the internals are concerned my goal is to have the external appearance to match the picture of the engine in the real boat.

 

Michael

 

   

[Jack12477]

What !? You don't have a Gleason Gear Cutting Machine in your garage, Michael !  (Just kidding of course).

 

Many (and I do mean many) years ago, I was shopping in a department store in my home town of Rochester NY where Gleason is located and on the main shopping floor Gleason had set up one of the smaller gear cutting machines and was giving  a demonstration. The machine was cutting the beveled ring gear for a Sears Sewing machine. When the machinist finished cutting the gear he gave it to me. I have it on my key ring - well worn. It was interesting to see exactly how the machine worked - it did not cut each slot sequentially but rather stepped about 15 degrees (or so) and cut another slot then another step of about 15 degrees and another slot; when it finally finished cutting the final slot was adjacent to the first slot cut.  Photo attached below:

 

 

I am really impressed and envious of your machining skills. The engine is magnificent !

Edited December 9, 2014 by Jack12477

[michael mott]

Shucks Jack, now you have spilled the beans Jude was trying to keep this present a secret

 

Michael

[Jack12477]

Now that's a machine ! Impressive !  Would be super nice to have that one in my garage.

 

Haven't kept up with my home town companies since I left there in 1968 even tho I still have family there - Dad, 2 brothers and 1 sister. Dad is 99 and going strong. He's very knowledge about Gleason's history. He told me once that Gleason was the only American company that was NOT affected by the Great Depression of 1929-1930.

 

Gleason offered me a job as a programmer when I got out of the Army but I didn't accept it because I took a more challenging programming job with "Big Blue" down here in the Hudson Valley and stayed for 40 years. We used to say we were on the "bleeding edge" of technology advances.

 

My only experience with machine shop was as a college freshman I was required to take a two semester Machine Shop course where our project was to machine a working micrometer from scratch. I still have the micrometer tho I don't use it much.

 

I'm really enjoying the engine build.

[michael mott]

Thanks for the likes .

 

I did make the casing today and fitted the gears inside.

 

the gear for the prop through the end that will be shaped with the cone recess.

 

 

The casing with the pinions and the drive gear which will be pinned to the crankshaft.

 

 

The cone end with the pinions dropped in and the gears lined up for the casing to slip over.

 

 

All dry assembled I also spotted three holes for some 0x80 bolts to ensure the casing and cone stay together and do not move relative to each other.

 

 

 

I did check the reverse by rotating the prop to see that it actually worked to this stage. still a long way to go to get it all mounted and working in situ.

 

It did work though so I am pleased about that.

 

Michael

[shipmodel]

Michael - 

 

Let me be the first to say how impressed I am - again.

 

Dan

[mtaylor]

I don't understand how this reverser works but that is one impressive bit of work.  Is there some sort of lever to put it into reverse? 

[Bedford]

I think I get it Michael, I'm guessing forward involves one pinion "linking" the two gears directly while reverse involves the first pinion moving off the output gear and driving the second pinion which will engage the output gear.

 

I'm not sure my eyes would be good enough to work at that scale.

[michael mott]

Dan, thank you.

Mark yes the drawing shows the lever, as the lever moves forward it causes the casing to be clamped. When the casing is stopped from revolving the drive gear rotates the first pinion which is in constant engagement with the second pinion (they are set in such a way that each pinion engages with only one gear), the second pinion drives the prop gear then in the opposite direction. when lever moves back towards the stern the casing is released from the band clamp and revolves, the pinions do not revolve inside the casing basically causing the drive and prop gear to be locked.

 

I took a short video this evening and it will be ready to upload in the morning showing the basic process.

 

Steve the above explanation should clarify the way it works.

 

Thanks for all the likes.

 

Michael 

[Bedford]

Got it !

I was thinking it might work like a differential in a car and it pretty much does, if you turn one axle with the drive shaft stopped so the diff centre can't turn, the other axle will go in the opposite direction. Free the drive shaft and allow the diff centre to turn and both axles go in the same direction. Obviously in this case there is no differential action, just locked and free, reverse and forward

 

Does that sound right?

[Jack12477]

Michael,  very impressive work ! 

[cog]

Michael,

 

Incredible work again. You keep on amasing your crowd. I'll stick to wind propulsion or a ready  to use (aka bought) engine. You are way, way, way out (above ..) of my leage

[michael mott]

As promised the short video of the gearbox in action.

 

michael

[Omega1234]

"Short", but powerful. A picture really does speak louder than words. Thanks for loading that up for us.

 

All the best!

[mtaylor]

Thanks Michael.  Here I was thinking the reverser was more like the one for a Lenco transmission as that's the only planetary transmission I'm remotely familiar with.  Not familiar with enough to tear down and rebuild, however.

Edited December 10, 2014 by mtaylor

[EdT]

Fascinating, Micheal.  I don't know what else to say.

 

Ed

[usedtosail]

Thanks Michel for the video. I am still not sure how it works, but you can' t beat visual evidence. Your machining of this engine is fascinating to me.

[michael mott]

Thanks everyone for the comments and Likes.

Its been a long couple of days working on the gearboxes, yes I ended up redoing the casing a couple of times over, I also opted to redo the inner stuff as well. Although the micro gears worked they were not as smooth as I wanted. I ended up using some 48DP "pinion wire" it is actually 10 tooth brass pinion, and is exactly 1/4 inch in diameter. this way I was able to go by the numbers and make the proper distances for the gears to mesh'

 

 

Like this Video

 

In order for the gearbox to be able to lock so that the prop rotates forward there is a clutch that is splined, I have been wracking my brains working at finding a way to make a small spline. This morning as I woke up it hit me.

 

 

Yup the trusty old allen head cap screw has a negative hex to accept the hex key, I matched up a 5/16 cap screw with some 1/4 inch hex brass. the steel collar will revolve in the base of the forward/reverse lever and will move about 1/64 to clamp the prop shaft to the gearbox causing the forward motion. the hex part will be pinned to the prop shaft, and a loose clamping collar will be inserted between the hex collar and the casing of the gearbox, when the lever is pulled back the hex collar will move forward clamping the case and loose collar hence locking the case to the prop-shaft

 

 

 

The revers is accomplished by clamping the gearbox inside a steel band which was made from some steel rings turned up and silver soldered together. As the gearbox is clamped the splined collar also releases the loose clamping collar allowing the gears inside to impart the reverse

 

 

The rings were machined to shape using the mill and the lathe.

 

 

 

 

When I cut the slot on the top of the band it automatically sprung to a smaller diameter which works in my favour because in order to open the band a wedge has to slide forward, this wedge is connected to the forward reverse lever.

 

It is getting there.

 

Michael

 

 

 

 

 

 

[Remcohe]

This is metalworking of a whole different league..... Splendid work Michael.

 

Remco

[Bedford]

Inventive work, I love it. You find what you want in other things like the socket head screws, brilliant!

 

The gearbox mark 2 looks very good, nice and smooth too.

[WackoWolf]

I agree with Remco, excellent metal work.

[Twister]

Wow!! Just got back from 68 degrees north where everything seems to become sub-minature to find it can all be done in the comfort of a workshop!!

 

Michael, your ingenuity continues to utterly confound me, I really am beyond impressed - congratulations!

 

Regards,

 

Row