Author Topic: Lauson LA build  (Read 17953 times)

Offline Admiral_dk

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Re: Lauson LA build
« Reply #30 on: February 22, 2018, 10:20:27 PM »
Great - I'm certainly looking forward to the journey ahead  :popcorn:

Offline Craig DeShong

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Re: Lauson LA build
« Reply #31 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 Iíve built, and Iíve learned that itís 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 Iíve already drilled out a starting hole and now Iím boring the ďto beĒ block for receiving the cylinder liner. 


The ďto beĒ block with bored hole, ready to receive the liner.  Iíve 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 Iím 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.  Iím not too worried about the inside diameter at this point.  After pressing the sleeve into the block Iíll make a few boring passes to accurately size the ID.   Here Iím just getting the OD to around .050 inch oversize.


Now Iím 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 Iím going back and finish the outside diameter.  Iím 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 Iím 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.  Iíll 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

Offline Craig DeShong

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Re: Lauson LA build
« Reply #32 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.  Iíll 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 Iíve built that will have them.  I thought Iíd 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 Iíve drilled and reamed the valve guide passages and am boring the chambers for the valve seats.


 
Progress so far.  Next Iíll fabricate the cast iron valve seats and guides.

« Last Edit: March 06, 2019, 02:23:41 PM by Craig DeShong »
Craig

Offline Dave Otto

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Re: Lauson LA build
« Reply #33 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 #34 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.  Iíll 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

Online b.lindsey

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Re: Lauson LA build
« Reply #35 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 #36 on: February 26, 2018, 10:36:44 PM »
Hi Bill.  Canít believe we live so close and havenít crossed paths.  We need to organize meeting at a show sometime this summer!

No, I didnít heat the aluminum.  With a .001 press fit at this size thereís 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 wasnít sure were going to goÖ 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

Offline Craig DeShong

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Re: Lauson LA build
« Reply #37 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 Iíve finished pressing one valve guide/seat into the block and Iím about to press the remaining one.  You might notice Iíve 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 donít 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 Iíve 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 Iím going to use my Volstro rotary milling head.  This is a VERY versatile addition to my Bridgeport mill; without it I donít 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 Iím milling the center radii



And Here Iíve just finished the end radii



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

 
« Last Edit: March 06, 2019, 02:35:04 PM by Craig DeShong »
Craig

Online b.lindsey

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Re: Lauson LA build
« Reply #38 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 #39 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

Offline Roger B

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Re: Lauson LA build
« Reply #40 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 #41 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 :(

Offline Craig DeShong

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

Iíve been working steadily these last few days, attempting to convert this chunk of aluminum into an engine block.  Iíve 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 Iím using a liner, Iím 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 isnít shown in the photo.



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



Iíve just finished forming the inside of the bearing plate mount and Iím also taking the opportunity to start removing some material from the crankcase.



Now Iím 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

Online b.lindsey

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Re: Lauson LA build
« Reply #43 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 #44 on: March 03, 2018, 11:23:47 PM »
Iíve 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 Iíve 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 didnít have any numbers to use to do this, this was more ďartĒ than engineering.  I was trying to achieve a curve that ďsort-ofĒ 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