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

[druxey]

Ouch! At least there was no personal damage beyond pride.

[NMBROOK]

More excellent work Michael May I make a suggestion.I don't know whether your tooling would allow it,but if the rotary table was mounted perpendicular to the mill table,could you mill the camshaft lobes using an end mill utilise a combination of vertical readout and rotary readout?I know you would have to do the opening and closing phases of the camshaft separately with the cutter set to opposing sides of the centreline to avoid 'digging in' in the ramp sections.Then again I may be overthinking the process .

I notice your liners are slightly shy of the block deck.Do you propose to use wills rings as your head gaskets?

 

Kind Regards

 

Nigel.

[mtaylor]

Ouch, indeed.  I thought I was the only one who "forgets" the tool is running.  

 

What the cam shops do is start with a solid billet, lathe to round, then while still on the lathe, make the cuts between the lobes and bearing points. They then set the billet up in the mill and do the lobes with an end cutter.   If they have access to them, some billets are preforged with the low points already there so they don't have to mill between the lobes and bearing points just true the bearing surfaces and then take to the mill. The stuff is all CNC controlled so I don't know how they do the offsets, etc. for the shaping.  Watching this is making me remember some things from a different era.... 

 

I think your plan is a good one... mill as one piece and then cut and pin to places needed.

Edited January 5, 2015 by mtaylor

[michael mott]

Druxey,Nigel, and Mark, thanks for looking in yes ouch indeed. 

I did a test cut this evening with the sharp nosed bit sideways and am going to cut the cam form as a single piece about 1 inch long.

 

 

  I am going to use the main gear that is normally used to set the headstock in back gear because it is a 60 tooth gear so I will set up an indent so as to lock the spindle in the 6 degree increments, the height of the cam is .022" from the cylindrical body so mapping out the 22 cuts using the gear to index I will be able to form the lobe then clean it up with files and wet and dry polish the hole thing then drill and ream for the 1/8th shaft

 

part off the cams and then locate them and set up a dial to position them drill for the pins then when doing the final assembly use some loctite as well as the pins

 

 

cams made on lathe.pdf

 

Thanks for all the likes

 

Michael

Edited January 5, 2015 by michael mott

[michael mott]

Nigel I had to look up what wills gaskets were. I will not be using them I am still deciding how to fix the head to the top of the cylinders my splitting it off was a compromise on my part because the original had it all cast as a single piece.

 

Some of the model engine builders have used a high temp J B-weld.

 

Michael

[EdT]

Very intricate and precise work, Micheal.  Very impressive.  Do you intend to harden the cams and followers for wear resistance?  It would be quite easy to do.

 

Ed

[michael mott]

Good morning Ed, thanks and yes I will harden them after the holes have been drilled.

 

Thanks to all who added likes today

 

I just looked at the PDF at 800% at the 10 to one image there you can see the clear incremental cuts, I am impressed I did not realize that I would get such good resolution in the PDF.

 

Michael

[Mirabell61]

good Job on that cam rod Michael

 

Nils

[shipmodel]

Hi Michael - 

 

Just back from 10 days vacation and was impressed with all the excellent work that you've done, and your similarly excellent explanations and photos.  I'm learning so much about engine construction and metalwork.

 

As the hula dancer said when the bovine nipped at her costume:  Moo Chews Grassy *** . . .

 

Be well

 

Dan

[michael mott]

thanks evreyone for the encouragements.

 

The cam cutting is working well a little slow but I am pleased with the way it is shaping up.

 

I made a small indent pin for the Myford this morning before starting on the shaping.

 

 

 

 

the wheel was progressively marked with the teeth that would be left out until I got to the 1/2 way mark from both sides of the lobe apex

 

 

the cutter was rounded a bit more after this cut

 

 

 

Still .008" to go before the final clean up.

 

Michael

[Bedford]

Lucky you have that 60 tooth gear on the lathe to index the work with, very convenient. 

 

Yet more very interesting and educational engineering going on, thanks!

[michael mott]

Steve thanks.

 

I finished up the rough shaping and polished the long form then cut the sections down to the root diameter.The lift ended up being .021" I can live with that.

 

 

 

the root sections are machined to  .156" diameter

 

 

bored reamed to .125" and parted off ready for pin holes in the root sections

 

 

slipped onto the .125 shaft.

 

Michael

 

 

[Chasseur]

Wow you remind me of the work my father in law used to do when he was younger. I can relate to your comments about the cold weather and the occasional brain fart!

"Sucks to get old as my father in law would say." Oh well a little humility goes a long way and the project is definitely first rate.

I checked out the videos and that was very informative.

Keep up the great work!

Blessings .... Jeff

[Twister]

Michael,

 

Quite simply, I'm in complete and utter awe!!

 

Regards,

 

Row

[michael mott]

Jeff, Row thanks for your comments, and to all who posted likes.

 

Spent some time today cutting up firewood so did not get as much time in the shop as I would have liked.

 

This evening I did manage to make a 75DP gear cutter took a long time to figure out how to hold the cutter in order to cut the gear using the shaping principles, the first attempt at making the tool to make the cutter I did not get the pins hard enough and the steel cutter blank damaged the pins so a second hardening did work. I rotated the pins to get a clean area for the tool.

 

The first gear blank turned out to be just some ground mild steel and did not harden at all. the second one was made from some 1/2 inch drill rod I also changed the type to an integrated shank and cutter.

 

The first pic shows the tool to make the cutter shaping the blank cutter.

 

 

the next shows the cutter after hardening and grinding the cutting face.

 

 

The next one is a quick test on some 3/8 diameter brass I just wanted to see how it cut this is a crude 30 tooth 75DP gear the final gear will need more care setting up the cutter to the tangent of the gear blank and the depth of cut will need proper measuring , but at least I know I can make one.

 

I still need to make a second cutter for the 60 tooth gear because the cutters are designed to cut a specific range, the one I made today is for gears ranging from 26 teeth to 34 teeth and is a number 4 cutter the other one is #2 cutter which has a range of 55 to 134 teeth.

 

Michael

[Chasseur]

Awesome work *Michael*

You rock my friend!

[michael mott]

Math is definitely not my strong point it seems. yesterday I spent a fair bit of time cutting the (30tooth) gear and as I came to the last tooth I could see that something was awry because I cut a half tooth.  Thinking I had skipped a tooth on the indexing I counted the teeth 32.5 noooooooooooo counted again 32.5.  I used a felt marker and recounted the big (60tooth) gear on the lathe 65 ..... 65!! . Somehow I had got it into my head that the big gear was a 60 tooth gear? hearsay ...myth,  a wild guess  I don't know.... what is the old saying about assumptions?

 

So one step forwards 5 steps back, a rethink of what to do next. All I know is that it involves setting up the rotary table in the vertical position on the mill which is what I ought to have done in the first place. It is just such a pain in the neck to do, because it is a very heavy bit of tooling, and really a bit too big for using as a dividing head, that is why i was so pleased that the gear on the lathe was a (60 Tooth one)perfect one for the job.

 

Oh Well....tis a good job that I am not getting paid for this and it is just my education that I am dealing with.... don't make assumptions you would think that I would have learned that one by now. Lesson learned!

 

to be continued

 

Michael

[popeye the sailor]

I think the word is 'assume'.........but I don't feel it applies here     your breaking new ground here.........I don't know too many folks who have done this.  whether you break one egg........or 30....in the process.....your still making progress,  and that's what counts!

[cog]

Lesson learned ... till the next time ... I know: been there, did it. Still, I couldn't do what you are doing right now, so keep it up

[Jack12477]

You're still light years ahead of me, Michael. I would not even know where to begin doing what you've already accomplished. Having spent a 30+ year career on the "bleeding edge" of computer technology myself, I can empathize. As many have said previously, you are blazing new ground and educating all of us in the process.  Your workmanship is amazing and truly inspiring. We are all enjoying the journey with you, including the occasional stumbles along the way.

[michael mott]

Row, Denis, Jeff, Carl, Jack, that you all so much for the encouraging remarks, they take the edge of these types of screw ups.

 

Thanks to all who are following along and noting it with the like button.

 

Today was a much better day nippy (-32 this morning)  but better.

 

I went back to square one with the tooling and reset the rotary table in the vertical position, and spent the time needed to get the chuck properly centered on the table with the dial indicator. I turned down some new stock to the .422" diameter the advantage to using the mill table and rotary is far greater accuracy can be achieved.

 

 

the depth of tooth cut can also be very accurately regulated the depth is .031" and I fixed the quill on the mill so that it could not rotate and unplugged the mill, then worked the table in the same manner as the compound slide on the lathe, in other words I used the mill like a shaper this time. I prefer the way the material finish occurs with the shaping cut versus the rotating cut.

 

 

The indexing was simply a matter of rotating the table in increments of 12 degrees.

 

 

Once the shaping of the teeth was completed the chuck went back onto the lathe to finish the other operations , drilling and boring to 1/8th and cutting the hub for pinning.

 

 

It cleaned up nicely and is now waiting for its big brother, on the camshaft, but i have to make a new cutter first.

 

 

Michael

 

[Remcohe]

In the end it just got better, it's only human to make a mistake once in a while. At least I do!

 

Remco

[Bedford]

So much learning! When you started this build I had no idea I would be following a master class in machining

[mikegerber]

Hello Michael

 

Already for a long time, I follow your logs and I ask myself all the time ...

... is there something you can not build?   

 

Your work is fantastic - pay tribute.

 

Regards

Mike

 

 

 

[michael mott]

 

... is there something you can not build?

Yes....... A Swiss Watch!

 

 

Thanks everyone for your compliments

Michael

[jud]

Your use of the lath and mill as a shaper is new to me, can't complain about not having a shaper. Like to spend some time with you, in your shop, asking dumb questions.

jud

[cog]

And that is the warm and fuzzy feeling you get after such a well manufactured chuck. Great work

[Twister]

Michael,

 

Superb machining yet again. It's nice to know I'm not the only one to make assumptions - it reminds me of the advice my father always used to give 'Measure twice, cut once'. Sometimes I can even manage to measure 3, 4 even 5 times and still get it wrong! Can't remember if it was here or an engineering website where I read something like 'I've cut this bolt three times now and it's still too short...'

 

Looking forward to seeing how the 60 comes out,

 

Regards,

 

Row

[michael mott]

 

Like to spend some time with you, in your shop, asking dumb questions.

Jud, thanks, regarding the shaping, the thing is I am taking very small cuts with the tool on a fairly forgiving material for the most part. The way the tools work on the lathe is mostly the work moves and depending on the diameter and shape of the tool the cutting will usually produce a nice smooth cut. Sometimes the cutter needs to be reshaped or lubricated to get the desired result, most of this has been learned by observing what happens when one tries something.

 

When I say that I am using the lathe or mill like a shaper, it is in the loosest way really, as you know on a shaper the tool is hinged so that on the back stroke the tool lifts and then the machine indexes over to make the next cut.

 

My tools are fixed and so the back stroke the tool stays in the same relative position. I am making very small cuts .005 max on the first cuts and backing off as the form tool gets deeper because it is doing more work, think of the chamfer on the corner of a piece of wood, as the chamfer gets wider more material is being cut by the plane or chisel, the same thing happens with the tools on the lathe.

 

The important thing is small cuts and keeping everything as rigid as possible. the last cuts on the gear teeth are repeated over 2 or 3 times without adjusting anything, the natural spring in the tools and materials take just that little bit extra material off in those last cuts, it is almost undetectable but it does matter for the final finish.

 

Each tooth on the gear takes a minimum of 15 cuts back and forth before moving on to the next tooth. it is a slow tedious process but satisfying because I can make what I need. I am 15 teeth into the 60 tooth gear at the moment and have to take little breaks to keep my sanity, and concentration level up, it is so easy to get lulled into a rhythm that causes a lack of attention and wham, a missed action or an additional one that can spell disaster, like this.

 

 

Just some thoughts about the way I work.

 

And again thanks for the likes

 

Michael

[Elia]

Michael,

 

My wife appears ready to call emergency medical technicians...  as I sit at my computer, silent, mouth agape, working my way page by page through your build log.  I am speechless.  This engine and gearbox are outstanding.  Truly.  

 

I have just a few questions on your design, fabrication, and assembly approach.  As all fabricated components have dimensions, and dimensional and positional tolerances, did you conceive a plan for dimensional tolerance management ahead of commencing with the machining of the components?  Or are there few enough 'stacks' of components that you can control individual parts dim's/tol's to allow assembly?  

 

I am now here and on board for the long haul.

 

With great respect,

 

Elia