Linford two stroke

[Davewild]

Hi guys


If you have read my other posts you will know I work offshore and have put together a portable machine shop to take with me, we'll I had it all packed ready to go and I got call from the office saying I would not be traveling for another week or so, impatience got the better of me and I unpacked it all set it up in my small back room and made a start on the cylinder, see pictures, I have one query if you have two parts that bolt together as an example an engine block and cylinder head do you drill the head first and then use transfer punches to mark the block and then drill, or do you drill both as separate items and hope that your accuracy will allow them to fit together?

Dave

 

[Davewild]

I don't know why but I can only upload one picture at a time, here's a pictures of the Linford two strokeengine by Jan Ridders

 

[Davewild]

Before unpacking

 

[Davewild]

Milling the flat on cylinder where it will bolt to the main frame.

 

[Davewild]

Using my new laser edge finder, the dot picked up by the camera is much bigger than reality.

 

[Davewild]

Tapping the first hole.

 

[Davewild]

Last hole finished, I hope there all in the right place

 

[Cogsy]

I'm just a beginner but I never trust my accuracy. I will always drill the through holes first and use transfer punches, although I suspect more experianced builders have no trouble matching bored holes.

Your parts look great so far, I'll be watching the build with interest.

 

[Brian Rupnow]

I have never, (if ever) used transfer punches. I use layout dye, and lay out the hole centers on each piece. Then I zero the piece in the mill (in a vice or bolted to the table with a sacrificial plate between the part to be drilled and the table) and use the dials to move the mill bed the correct number of thousandths of an inch in X and Y axis until it is centered under the quill in both planes. I then use a center drill to start the hole, and the laid out lines in the dye confirm whether or not I am truly drilling in the correct position or not. The first year or so, it was always quite a challenge to drill two different parts independently and expect perfect alignment of all the holes. Now I don't even think about it much. I do not have DRO's on my machines.---Brian

 

[Davewild]

I'm just a beginner but I never trust my accuracy. I will always drill the through holes first and use transfer punches, although I suspect more experianced builders have no trouble matching bored holes.

Your parts look great so far, I'll be watching the build with interest.

Thanks Cogsy, I'm a beginner myself, I'm undecided if to use transfer punches or not.

Dave

 

[Davewild]

I have never, (if ever) used transfer punches. I use layout dye, and lay out the hole centers on each piece. Then I zero the piece in the mill (in a vice or bolted to the table with a sacrificial plate between the part to be drilled and the table) and use the dials to move the mill bed the correct number of thousandths of an inch in X and Y axis until it is centered under the quill in both planes. I then use a center drill to start the hole, and the laid out lines in the dye confirm whether or not I am truly drilling in the correct position or not. The first year or so, it was always quite a challenge to drill two different parts independently and expect perfect alignment of all the holes. Now I don't even think about it much. I do not have DRO's on my machines.---Brian

Thanks for the info Brian, the reason I asked is because each end of the cylinder has a head bolted to it, this calls for a bolt pattern at a 14mm radius from the centre of the cylinder, obviously the center of the cylinder is no longer there( already bored) so how do I know find a centre to work from, do I fill the hole with a tight fitting temporary plug, or is there another method that you use? I just been reading your build thread and will use your method for cylinder honing as this is not yet done, I think once i have finished this engine i will build your Rupnow. Hope you can help and thanks again.

Dave

 

[Davewild]

Didn't get much time in today, but did manage to make two pistons the first was a failure(to small) and became a measuring device for the second which turned out great and after much lapping is a great fit, maybe one more tomorrow.

Dave

 

[Brian Rupnow]

Dave I'm not sure if you are using a rotary table on the mill to position your cylinder or a vice. Generally what I do, (and seem to get away with) is the following. If you are holding the round cylinder in a 3 jaw chuck on a rotary table, I do the following. I have a piece of 1.5" dia. round stock x 1.5" long, faced square on each end with a 3/8" hole reamed in the center of it, (done on my lathe). I also have a piece of 3/8" round stock that is a precision fit into the hole. I clamp the piece with the hole in the 3 jaw on the rotary table, making certain that the face closest to the chuck is setting down flat against the chuck face. Then I clamp the 3/8" dia. piece in the quill chuck, and move the table around until the 3/8" dia. piece will lower into the hole in the larger piece with no binding. At that point, I have effectively found "0" and can loosen the chuck, remove my set up piece, and put the round cylinder in the chuck. Then use ordinate dimensions to put in whatever holes I may want in the end of the cylinder. If the cylinder is not round, or some non uniform shape, then I clamp it in the mill vice, turn a round spigot that will be a precision fit in the hole in the end of the cylinder, and go through the same procedure for centering the quill over the cylinder.---Brian Rupnow

 

[Davewild]

Dave I'm not sure if you are using a rotary table on the mill to position your cylinder or a vice. Generally what I do, (and seem to get away with) is the following. If you are holding the round cylinder in a 3 jaw chuck on a rotary table, I do the following. I have a piece of 1.5" dia. round stock x 1.5" long, faced square on each end with a 3/8" hole reamed in the center of it, (done on my lathe). I also have a piece of 3/8" round stock that is a precision fit into the hole. I clamp the piece with the hole in the 3 jaw on the rotary table, making certain that the face closest to the chuck is setting down flat against the chuck face. Then I clamp the 3/8" dia. piece in the quill chuck, and move the table around until the 3/8" dia. piece will lower into the hole in the larger piece with no binding. At that point, I have effectively found "0" and can loosen the chuck, remove my set up piece, and put the round cylinder in the chuck. Then use ordinate dimensions to put in whatever holes I may want in the end of the cylinder. If the cylinder is not round, or some non uniform shape, then I clamp it in the mill vice, turn a round spigot that will be a precision fit in the hole in the end of the cylinder, and go through the same procedure for centering the quill over the cylinder.---Brian Rupnow

Thanks so much Brian as I don't yet have a rotary table, I will go with the second choice, won't get much machine time in over the weekend as my son requires my undivided attention, next installment will be on Monday, have a great weekend and thanks again.

Dave

 

[Davewild]

Hi all,

I hate to admit it but I ended up making 4 pistons but I am happy with 2 of them, I also decided to tackle the fuel tank/vapor carburetor as I know once the engine is finished I would not want to spend time making a fuel tank with the engine so close to running.

Dave

 

[Davewild]

Still cannot upload more than one picture, is it because I'm using an IPad?

 

[Davewild]

Not very happy with the sight glass, any tips on how to cut a 40mm dia glass circle?

 

[Davewild]

Oops 4 pistons, I only need 2

 

[Davewild]

Made some more small parts for the vapor carburetor today, took me 4 1/2 hours to make just these two small parts, I can't believe how many separate operations were involved in making them, is it my inexperience or do some of these parts just take time?

 

[Davewild]

Right at the last parting off, it came loose in the chuck and put some scores on it.