Author Topic: Lauson LA build  (Read 29962 times)

Offline Craig DeShong

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Re: Lauson LA build
« Reply #30 on: February 23, 2018, 11:16:39 PM »
We had another warm, beautiful day here in North Carolina, and though I had some errands to run in the morning, I managed to squeeze in some shop time in the afternoon.


This is the fourth of these little single cylinder Lauson engines I’ve built, and I’ve learned that it’s wise to press in the cylinder liner and valve guides before too much stock is removed from the bottom of the crankcase.   That being said, I decided to get these tasks over with first hand.  Here I’ve already drilled out a starting hole and now I’m boring the “to be” block for receiving the cylinder liner. 


The “to be” block with bored hole, ready to receive the liner.  I’ve made it a habit to label everything in an attempt to cut down on the confusion and eliminate stupid errors.  In my last build I bought a piece of aluminum, sized it appropriately, and then proceeded to drill mounting holes at right angles to where they should have been. :wallbang:


Somebody gave me these cast iron cored castings a while back.  This one is perfectly sized for use as the cylinder liner for this engine.  Here I’m making a facing cut to square the end of the piece.


The procedure I use for these cylinder liners is to get the outside diameter to a .001 inch press fit to the block.  I’m not too worried about the inside diameter at this point.  After pressing the sleeve into the block I’ll make a few boring passes to accurately size the ID.   Here I’m just getting the OD to around .050 inch oversize.


Now I’m going to bore out the inside diameter to around .050 of an inch under the finished dimension. 


Inside boring operation complete


With the inside diameter appropriately sized I’m going back and finish the outside diameter.  I’m doing all this to try to minimize any out-of-round conditions that might result from internal stresses in the material.  Probably over kill.


With the sleeve finished to its outside diameter of .001 inch over the hole I bored in the block I’m parting it off the base stock.


Here is the cylinder sleeve, ready to be pressed into the block.  I would have gone ahead and done this today but it was getting late and this is not something you want to hurry.  I’ll have lots of time tomorrow (or the next day?) to do this right and unhurried.
« Last Edit: March 06, 2019, 02:12:39 PM by Craig DeShong »
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline Craig DeShong

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Re: Lauson LA build
« Reply #31 on: February 24, 2018, 09:58:18 PM »
Work continued today.

It occurred to me, after making my post yesterday, that this audience (at modelenginemaker.com) is somewhat more mature (in metal working processes at least :)) that my usual audiences; so I will apologize for spamming you in my last post with needless pictures.  I’ll attempt to post only relevant ones in the future.



Today I pressed the cylinder liner into the block.  A little assembly lube made sure there would be no galling.



This engine will have valve lifters, the first one of these little guys I’ve built that will have them.  I thought I’d go ahead and mill out the valve chamber now (where the valve springs will be inserted) so I could see if there might be any problems, and also to shorten the length of aluminum I needed to drill through for the valve guides and lifter guides, hopefully minimizing the drill tip wandering.



Here I’ve drilled and reamed the valve guide passages and am boring the chambers for the valve seats.


 
Progress so far.  Next I’ll fabricate the cast iron valve seats and guides.

« Last Edit: March 06, 2019, 02:23:41 PM by Craig DeShong »
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline Dave Otto

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Re: Lauson LA build
« Reply #32 on: February 24, 2018, 11:37:04 PM »
Looks like your off to a good start.


Dave

Offline Roger B

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Re: Lauson LA build
« Reply #33 on: February 26, 2018, 01:09:18 PM »
It occurred to me, after making my post yesterday, that this audience (at modelenginemaker.com) is somewhat more mature (in metal working processes at least :)) that my usual audiences; so I will apologize for spamming you in my last post with needless pictures.  I’ll attempt to post only relevant ones in the future.

There are also plenty of beginners out there who appreciate the details of how to set things up, who much overhang you can get away with etc. If you think it is interesting post it.

Looks like you are well under with this one  :ThumbsUp:  :ThumbsUp:
Best regards

Roger

Offline b.lindsey

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Re: Lauson LA build
« Reply #34 on: February 26, 2018, 03:03:19 PM »
Lots of great progress Craig. I see a lot of similarities to the 1950 B&S 6s, especially in the valve spring area you are working on now. Following along with interest and nice to see the first chips flying onthe Lauson. On the liner press fit, did you heat the aluminum block at all or just "press?"

Bill

Offline Craig DeShong

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Re: Lauson LA build
« Reply #35 on: February 26, 2018, 10:36:44 PM »
Hi Bill.  Can’t believe we live so close and haven’t crossed paths.  We need to organize meeting at a show sometime this summer!

No, I didn’t heat the aluminum.  With a .001 press fit at this size there’s enough movement for things to slip together.  Assembly lube really helps.  This is a pretty easy press, not much pressure required; NOTHING   like the press fit when I pressed the drivers onto my locomotive; there were one or two I wasn’t sure were going to go… but they did.

BTW- did I see your Briggs at cabin fever a few years ago?  One was there and it was GORGEOUS !
« Last Edit: February 26, 2018, 10:40:51 PM by Craig DeShong »
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline Craig DeShong

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Re: Lauson LA build
« Reply #36 on: February 26, 2018, 10:37:39 PM »
Today I finished the fabrication of the valve seats and guides.  I make these as one part and then press them into the block.  Here is a view of them just prior to insertion into the block.



I use my hand press for the pressing operation.  Here I’ve finished pressing one valve guide/seat into the block and I’m about to press the remaining one.  You might notice I’ve fabricated a tool to assist with the pressing operation.  This allows me to place equal pressure on the lip of the valve seat and on the top of the valve guide.  I don’t want to fracture one of these pieces while inserting it into the block. 




The block with the valve seats and guides inserted.

 

There were a lot of choices on how to proceed next.  I choose to continue with the upper head porting.  Here I’ve just drilled the exhaust passageway from the outside of the block into the valve chamber.



Next I moved on to the intake passage.  Here I needed to fabricate the intake manifold flange.  To form the flange I’m going to use my Volstro rotary milling head.  This is a VERY versatile addition to my Bridgeport mill; without it I don’t believe I could have built any of my models.  This tool allows me to mill arcs around the center of the Bridgeport spindle.  Its use is like a rotary table, but I find it much more flexible.



In fabricating this flange using the rotary milling head I needed to know the angles where the curves transition to tangents.  Fortunately. I can get that information from the CAD drawings as shown.  For the end radii of this flange I need to mill 68 degrees from both sides of the centerline.  For the center radii I need to mill 22 degrees from the perpendicular.  Both these measurements can be directly measured off the rotary milling head.



Here I’m milling the center radii



And Here I’ve just finished the end radii



Finally, two views of the progress so far.  It’s starting to look less and less like some non-descript chunk of aluminum and more like… well something.

 
« Last Edit: March 06, 2019, 02:35:04 PM by Craig DeShong »
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline b.lindsey

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Re: Lauson LA build
« Reply #37 on: February 27, 2018, 12:16:41 AM »
You are moving right along Craig. Lovely work too!! You are in the Raleigh area right? My youngest daughter is there and I get up there occasionally to see the grandsons. Hopefully more often once I retire. What shows do you normally attend?

Bill

Offline Craig DeShong

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Re: Lauson LA build
« Reply #38 on: February 27, 2018, 12:25:36 AM »
Thanks Bill.  I'll be at the Lillington show March 17th.  I think the Benson show would be next.  Don't  have a date for it yet.
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline Roger B

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Re: Lauson LA build
« Reply #39 on: February 27, 2018, 07:13:29 AM »
I've seen pictures of a Volstro rotary milling head but never seen one in use, interesting  :)
Best regards

Roger

Offline Pete49

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Re: Lauson LA build
« Reply #40 on: February 28, 2018, 02:52:32 AM »
I'll be following with interest. My mother had a washing machine like that but it used a Villiers engine. Same method to start and I got to start it while on school holidays and thought I was great as an 8 year old. Might have had a reason I went to motorbikes before electric start came in on them. :Lol:
I used to have a friend.....but the rope broke and he ran away :(....Good news everybody I have another friend...I used chain this time :)

Offline Craig DeShong

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Re: Lauson LA build
« Reply #41 on: March 01, 2018, 09:53:42 PM »
Thanks for all your replies, I really appreciate the interest.

I’ve been working steadily these last few days, attempting to convert this chunk of aluminum into an engine block.  I’ve removed a lot of material so far, and there is a lot more yet to be done.

The first step was to bore the cylinder liner to the correct dimension.  The scale bore for this engine would be 1.25 inches.  Since I’m using a liner, I’m going with 1.125 inches.  I would have needed to over bore the block in order to use a liner large enough to bore to scale and that would have resulted in possible mechanical failure of the block.  The material gets incredibly thin in the cylinder area once the fins have been cut.  While I was at it I cut the valve seats though this isn’t shown in the photo.



I’ve just included several photos from the work that’s been done.  There are a lot of steps involved in making a block that resembles the full size engine.  Here I’m machining the mounting boss for the PTO side bearing plate.



I’ve just finished forming the inside of the bearing plate mount and I’m also taking the opportunity to start removing some material from the crankcase.



Now I’m working on the other side of the block, forming the boss for the magneto side bearing plate.



Two pictures of the work so far.  There remains lots of metal to remove in the crankcase area and lots of detailing to do.


« Last Edit: March 06, 2019, 02:42:45 PM by Craig DeShong »
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline b.lindsey

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Re: Lauson LA build
« Reply #42 on: March 01, 2018, 10:36:38 PM »
It's taking shape Craig. Looking like a proper engine block now and nice to follow your rapid progress.

Bill

Offline Craig DeShong

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Re: Lauson LA build
« Reply #43 on: March 03, 2018, 11:23:47 PM »
I’ve spent the last several days clearing material out of the crankcase and forming the curved bottom of the block. 

The removal of material from the crankcase was tedious work, made more difficult by the inability to thoroughly lubricate the end mill (due to confined spaces) and we all know that aluminum need LOTS of cutting oil to prevent aluminum from adhering to the working edge of the end mill.  I have no pictures of this work; it would have been difficult to show you, indeed it was difficult for me to see what was going on.

I do have a picture of how I formed the curves on the bottom of the block.  This is a compound curved surface and the method I choose used one of the more bizarre setups I’ve had occasion to use.  The curve was formed by multiple passes, changing the arc radius, changing the center of the arc, and changing the tilt on the mill head.  I didn’t have any numbers to use to do this, this was more “art” than engineering.  I was trying to achieve a curve that “sort-of” matched the full size, realizing that some filing and belt sanding would finish the job.



Three pictures of the progress so far. 





« Last Edit: March 06, 2019, 02:48:02 PM by Craig DeShong »
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline 10KPete

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Re: Lauson LA build
« Reply #44 on: March 04, 2018, 01:14:58 AM »
I envy the heck out of you having a Volstro at home.  :P

I used one regularly 30 years ago and found it to be just about the handiest thing around!

This engine is really shaping up beautifully.

 :cheers:

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

 

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