Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine

[zeeprogrammer]

Looks fine for me.

I can also see the drawings from the initial two links.
I have to admit...I don't think I checked last time.

I think you're good to go.

[toolznthings]

We are good on the pictures now . 

[mikehinz]

Today's work on the engine. 

First project for today, working on the base and getting it completed!

Spot drilling for the various thru-holes plus spot drilling the corners of the flywheel cutout area.


Drill the thru holes and corners of the cutout with a #9 drill (clearance for 10-32 shcs).  Using the DRO with 0,0 at the lower left corner.


Milling out the flywheel clearance area.  I'm using a 1/4" 2 flute HSS end mill.  Plunging in about ,100 on each pass.


Base is completed! 



Started on the cylinder.  Got the setup done and drilled and tapped the 10-32 holes for the cylinder head cover SHCS's.  I just used the spindle and chuck as a guide.  I put a bit of pressure on the quill handle and rotated the spindle by hand with the Bridgeport kicked into neutral.  I sometimes use a tap follower but this is easy and quick for 10-32. 


You might note that the cylinder bore is a bit small!  I better get that fixed up tomorrow!

I have a couple of questions I was hoping someone could answer.

- What's the best way to improve the finish of AL?  The base was correct in thickness so I didn't want to fly-cut if and make it under size.  How about a Scotchbright wheel? 

- On the flywheel cutout area, the milled out area was not perfectly smooth on the edges.  Is the best way to get a better finish to stay on the inside say .005 during the plunge cuts and then take a very shallow finishing pass at full depth?  Or just work the edge smooth by filing or sanding? 

Next step(s) is to finish the cylinder and then start on the column.  I'm still not happy with the drawing for it so I need to work on that for a bit.

In any case enjoy!

Mike.

[mikehinz]

I THINK the photos should all be correct on my latest post but please comment if anything is missing or doesn't seem correct.

Thanks.

Mike.

[crueby]

The pics seem to all be there!


 

[zeeprogrammer]

Very odd. The 1st 3 pics show fine. The last 2 show the 'no parking' or 'no entry' sign (I can't remember which).

As to your questions...I'm too inexperienced to help...but no doubt others will chime in. It's a great forum.

[b.lindsey]

Mike, on flat pieces like the base, I usually finish them up on a flat plate with 320 or 400 grit sandpaper which will leave a nice matte finish. As for the flywheel cutout, if your set up is rigid, you can climb cut say .005" all the way around and it will leave a smoother finish.

Bill

[mikehinz]

Today's work on the engine:

I decided that boring the cylinder wasn't a good idea at this point.  Per the original drawings which I duplicated, the cylinder contact area to the column has a large radius turn on it and then a recess behind that turned to a smaller radius.  Since I'm going to do that a 4 jaw chuck on the lathe, I thought I'd better leave as much material in place where the chuck jaws will end up touching.  Plus I needed a way to get close to center for the lathe work.  So i flipped the cylinder in the mill and drilled a center hole plus I went ahead and drilled the air admission ports at the same time since the work was located for doing so:


Then, since I had the 3 jaw chuck installed on the lathe, I went ahead and turned the cut stock for the flywheel to 1.00" thickness and drilled a center hole.  My plan is to then do the rest of the drilling and reaming in the mill, and once the crankshaft is made and pressed into the flywheel, I'll then go back to the, hold the crankshaft in a collet and lightly true up the flywheel.  Hopefully that will mean it will all run true when I'm finished!


Then back to the mill and locate the column in the vise, bottom up.  Then drill and tap the holes for attaching the column to the base:


Just a photo of something I always try to do.  I chamfer the drilled hole fairly aggressively.  That way the tap seems to start more easily and there's no nasty burr after the tapping operation:


The first 2 pieces assembled!  One small step, something, something, something...............


Finally, just mocking things up to get an idea of the scale and how it all will look when finished.  I just took Elmer's plans and pretty much doubled all the dimensions.  I think the cylinder looks a bit large at 2X scale, but we'll see when it's all done:


I do have a question:  Is the collective wisdom to bore the cylinder on the lathe with a boring bar or to bore the cylinder on the mill with a boring head?  The setup in the 4 jaw is a bit more painful, although i did have the foresight to put in a centerhole on the mill.  Input is appreciated!

All for today.  I'm still working on finalizing all the various 2d drawings for construction and am still trying to animate this thing in Fusion 360.  I may end up taking a break from working on this engine for a day or 2 as I've just received the DRO kit for my lathe and I'd like to get that installed although I don't really need it badly for this engine project.  So, who knows what I'll do!  I'll just follow whatever impulse strikes me!

FYI.

Mike

[zeeprogrammer]

Just a photo of something I always try to do.  I chamfer the drilled hole fairly aggressively.  That way the tap seems to start more easily and there's no nasty burr after the tapping operation:

That's something I try to remember to do but generally fail at. I always think there's some steps I'm forgetting to do. I hope I'm getting better at it.
You're a step a head of me.

[AOG]

It looks good so far. I have to say, that engine looks beefy and industrial at that scale. My personal opinion on the cylinder  is to bore it on the lathe and then skim the face to make sure it’s perpendicular to the bore. Just my 2 cents.

Tony

[toolznthings]

Hi,
Look at my Elmer's #32 post to see if you like the procedure I use for boring the cylinder in the lathe. Eaiser to indicate and accurate. IMO

Brian

[mikehinz]

Brian, I found the thread you're referring to.  I'll study it carefully as to your technique.

Thanks!

Mike

[mikehinz]

I have a runner, well virtually at least!

<a href="https://www.youtube.com/watch?v=E6OXisCQRDE" target="_blank">http://www.youtube.com/watch?v=E6OXisCQRDE</a>

I had some various bits of family business to attend to and that kept me from working in my shop, but I also spent a considerable amount of time on the Fusion 360 model for this engine and finally was able to understand joints and all the complexity associated with them.  After things clicked into place in my mind, I was able to animate the solid model fairly quickly.   By doing so, I was able to prove that I don't have interference issues and extremely importantly, I was able to verify that the porting on the column matches the porting on the cylinder at the correct positions.  I really, really came to appreciate Fusion 360 for this sort of design and verification and I'm glad I spent the time to learn it so as to become at least somewhat proficient with it. 

I also carefully generated all the drawings for this engine and repeatedly checked them over.  I did catch a few mistakes, some of my own making and some inherited from the original drawings.  I do have a question about the drawings.  I'm likely to revise them further as I make the various bits so where and how should I post them?  I do note that there's a Plans and Drawings forum.  Should i post the complete set there?  What happens if I make further corrections/mods as I go along?  Can I update the file easily?   Or should I just like it to my Google Drive folder and that way things would stay current?  Advise is appreciated!  Also, what about sharing the Fusion 360 model?  I certainly don't mind sharing it but I only want it to be downloaded, not modified online. 

In any case, I think tomorrow I'm going to do the various shafts and try to finish the flywheel.  Then on to the column with all it's tricky drilling!

FYI.

Mike

[zeeprogrammer]

That's fantastic! 

Getting a drawing to do what you need is a big step towards making parts.
I really enjoy CAD. I'm still looking for cam animation.

[b.lindsey]

A second to what Tony said. Bore in the lathe with the 4 jaw. That way the skim cut on the face will be perpendicular to the bore. Easier to do that on the lathe than the mill IMO.

Bill