fcheslop
Well-Known Member
Hi Kaleb,nice job you are doing on this engine but I think that wobbly thread may cause a little binding on assembly.
best wishes frazer
best wishes frazer
The Frank Wiggins "S.T." double acting oscillator of 1943
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Kaleb
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Here's some more work I've done over the last few days:
I decided to mill the sides of the base to make it easier to hold for drilling.
The base is clamped in the quick vice like so with a 4mm end mill in the lathe chuck.
Milling one side. All sides were milled without removing the job from the vice.
I decided to use an end mill for drilling the mounting holes since it does not wander. Sorry about the blurry photo, but my camera was refusing to play ball.
The base is then turned around to square the end of the piece which the crankshaft will run in. It is held in place with a G-clamp since the vice would not open far enough. I used a 12mm end mill this time to cover the whole area in each pass.
Milling underway. I did this operation in several light cuts.
The vertical slide is moved down to mill the area behind the port face. It is done in the same way as the last operation.
The workpiece is then turned around to mill the area on the other side from where the first operation was carried out. That's a toolmaker's style clamp I made in high school metalwork class. Knew I'd find it handy someday.
The port face itself was filed smooth as recommended by Stan Bray in his book covering the construction of several different oscillating engines.
The base is now finished except for the trunnion hole, porting and a bit of lapping.
I then turned my attention back to the cylinder. The plans call for the trunnion to be held to the cylinder by a screw thread. To ensure the hole is exactly where I want it, I start with a centre drill. I had previously marked out the port face to assist in the set up.
Starting the hole.
There's not much metal between the port face and the cylinder bore, so I wanted to be sure I didn't go right through. I used a ruler to make a mark on the drill bit with a texta so I knew exactly when to stop. If you look closely, you should see the mark.
To be doubly sure, I moved the drill back into the chuck to the mark so it can't go any deeper.
Drilling the hole to depth.
I then clamped an M3x0.5 tap in the chuck and turned it by hand, but I needed the thread to go right to the bottom of the hole.
The tap towards the top is a regular intermediate tap. This is fine for most jobs except where the thread must go to the bottom of a hole. The tap beside it is a bottoming or plug tap. It will cut a thread right to the bottom, but cannot start a thread like a taper or intermediate tap can. The bottoming tap was used to take the thread right to the bottom.
Here are a couple of photos taken while making the trunnion showing the collet chuck on my Hercus lathe.
The collet chuck really comes into its own when working with small diameters.
Here's how it looks so far. The black colouring on the cylinder is due to me needing to silver solder the trunnion in place and using waste oil to leave residue to prevent silver solder wetting where I didn't want it.
I decided to mill the sides of the base to make it easier to hold for drilling.
The base is clamped in the quick vice like so with a 4mm end mill in the lathe chuck.
Milling one side. All sides were milled without removing the job from the vice.
I decided to use an end mill for drilling the mounting holes since it does not wander. Sorry about the blurry photo, but my camera was refusing to play ball.
The base is then turned around to square the end of the piece which the crankshaft will run in. It is held in place with a G-clamp since the vice would not open far enough. I used a 12mm end mill this time to cover the whole area in each pass.
Milling underway. I did this operation in several light cuts.
The vertical slide is moved down to mill the area behind the port face. It is done in the same way as the last operation.
The workpiece is then turned around to mill the area on the other side from where the first operation was carried out. That's a toolmaker's style clamp I made in high school metalwork class. Knew I'd find it handy someday.
The port face itself was filed smooth as recommended by Stan Bray in his book covering the construction of several different oscillating engines.
The base is now finished except for the trunnion hole, porting and a bit of lapping.
I then turned my attention back to the cylinder. The plans call for the trunnion to be held to the cylinder by a screw thread. To ensure the hole is exactly where I want it, I start with a centre drill. I had previously marked out the port face to assist in the set up.
Starting the hole.
There's not much metal between the port face and the cylinder bore, so I wanted to be sure I didn't go right through. I used a ruler to make a mark on the drill bit with a texta so I knew exactly when to stop. If you look closely, you should see the mark.
To be doubly sure, I moved the drill back into the chuck to the mark so it can't go any deeper.
Drilling the hole to depth.
I then clamped an M3x0.5 tap in the chuck and turned it by hand, but I needed the thread to go right to the bottom of the hole.
The tap towards the top is a regular intermediate tap. This is fine for most jobs except where the thread must go to the bottom of a hole. The tap beside it is a bottoming or plug tap. It will cut a thread right to the bottom, but cannot start a thread like a taper or intermediate tap can. The bottoming tap was used to take the thread right to the bottom.
Here are a couple of photos taken while making the trunnion showing the collet chuck on my Hercus lathe.
The collet chuck really comes into its own when working with small diameters.
Here's how it looks so far. The black colouring on the cylinder is due to me needing to silver solder the trunnion in place and using waste oil to leave residue to prevent silver solder wetting where I didn't want it.
Kaleb
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I've made progress over the last week or two, and it's really coming together.
The trunnion of course needs a nut to tension the spring.
So I set up a piece of brass in the Hercus with the matching collet.
Facing the end of the stock.
Turning to size.
Centre drilling for the live centre.
Since I had made the 12mm (1/2") American toolpost, I decided to put a big J&S knurling tool that came with the Hercus into use. For this operation, I ran the lathe in the slowest back gear to reduce the strain placed on the tool.
Drilling a 2.5mm hole to take an M3x0.5 tap.
To tap my threads straight, I grip the job in the lathe, and grip the tap in the Jacobs chuck, and turn the Jacobs chuck by hand.
The workpiece was then transferred to the Sieg lathe and faced.
Finally, the nut is parted off.
Here it is in place with a spring wound from some thin music wire.
Next came the big end. I started by facing another piece of brass rod. I did it in the Sieg lathe this time since the Hercus was having some belt trouble.
Centre drilling the end.
Turning a length down to diameter.
Parting off.
Drilling a 2mm hole to take an M2.5x0.45 tap.
Tapping the hole.
Turning the shoulder.
Parting the piece off.
To drill the hole for the crankpin, the big end was set up in the 4-jaw chuck and flattened on one side with a 3mm end mill.
A centre drill was then used to start the hole.
Drilling the hole to 1/8" right through.
The finished big end in place on the engine.
The crankshaft set up for drilling the web for the crankpin. The plans called for a 2-piece crankshaft made from cold rolled steel, but I have decided on a 3-piece design with a shaft made from stainless photocopier shaft and a brass web and pin.
Starting the hole with a centre drill.
Drilling the hole to 3/32".
Next came the crankpin. I made this from a bit of thin brass rod I found at the scrapyard one day. First the rod is centre drilled.
Turning the rod down to a bit under 1/8" as per the plans.
Parting off.
Now for the flywheel. The plans called for this to be made from cold rolled steel, but I decided to make mine from brass. The workpiece was firstly faced.
The hole through the hub was then started with a centre drill.
Then drilled to 4mm right through.
To do the rest of the machining operations, I decided to make a mandrel. First a piece of 6mm photocopier shaft is centre drilled.
Then turned down to 4mm and threaded M4x0.7 part way down.
The flywheel is secured to the finished mandrel with a pair of nuts.
Turning the outside of the flywheel.
That's all for now, but an update should be coming soon.
The trunnion of course needs a nut to tension the spring.
So I set up a piece of brass in the Hercus with the matching collet.
Facing the end of the stock.
Turning to size.
Centre drilling for the live centre.
Since I had made the 12mm (1/2") American toolpost, I decided to put a big J&S knurling tool that came with the Hercus into use. For this operation, I ran the lathe in the slowest back gear to reduce the strain placed on the tool.
Drilling a 2.5mm hole to take an M3x0.5 tap.
To tap my threads straight, I grip the job in the lathe, and grip the tap in the Jacobs chuck, and turn the Jacobs chuck by hand.
The workpiece was then transferred to the Sieg lathe and faced.
Finally, the nut is parted off.
Here it is in place with a spring wound from some thin music wire.
Next came the big end. I started by facing another piece of brass rod. I did it in the Sieg lathe this time since the Hercus was having some belt trouble.
Centre drilling the end.
Turning a length down to diameter.
Parting off.
Drilling a 2mm hole to take an M2.5x0.45 tap.
Tapping the hole.
Turning the shoulder.
Parting the piece off.
To drill the hole for the crankpin, the big end was set up in the 4-jaw chuck and flattened on one side with a 3mm end mill.
A centre drill was then used to start the hole.
Drilling the hole to 1/8" right through.
The finished big end in place on the engine.
The crankshaft set up for drilling the web for the crankpin. The plans called for a 2-piece crankshaft made from cold rolled steel, but I have decided on a 3-piece design with a shaft made from stainless photocopier shaft and a brass web and pin.
Starting the hole with a centre drill.
Drilling the hole to 3/32".
Next came the crankpin. I made this from a bit of thin brass rod I found at the scrapyard one day. First the rod is centre drilled.
Turning the rod down to a bit under 1/8" as per the plans.
Parting off.
Now for the flywheel. The plans called for this to be made from cold rolled steel, but I decided to make mine from brass. The workpiece was firstly faced.
The hole through the hub was then started with a centre drill.
Then drilled to 4mm right through.
To do the rest of the machining operations, I decided to make a mandrel. First a piece of 6mm photocopier shaft is centre drilled.
Then turned down to 4mm and threaded M4x0.7 part way down.
The flywheel is secured to the finished mandrel with a pair of nuts.
Turning the outside of the flywheel.
That's all for now, but an update should be coming soon.
lazylathe
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Nice work so far Kaleb!!
Just to go back to another thread everyone was talking about...
I see you part using a live center in the tailstock.
Any reason for this?
Has it caused you any trouble with the work piece getting caught?
Andrew
Just to go back to another thread everyone was talking about...
I see you part using a live center in the tailstock.
Any reason for this?
Has it caused you any trouble with the work piece getting caught?
Andrew
Good progress so far K'. I couldn't happen but to notice in one of your images that you left the chuck wrench in the chuck while you were doing something else. I hope you do not have that habit. Remove it and set it down on the bench each and EVERY time you will be taking your hands off of it, even for just a few moments. Forgive me if I sound harsh but seeing that made me want to scream.
BC1
Jim
BC1
Jim
Kaleb
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About time for an update on this engine.
Here are some more shots of the crankshaft being made:
To ensure the crankshaft runs freely, I decided to lap it to the bearing with toothpaste.
The next shots show the making of the crank web.
Finished except for the crankpin.
A quick shot showing how I wound the spring.
Now, back to the stuff I haven't covered yet.
Turning the flywheel down for a belt groove.
Machining a recess into one face.
The flywheel is then set up in the Sieg lathe's milling attachment to put a hole in for a grubscrew.
Starting the hole with a centre drill.
Drilling the required diameter.
The engine frame has two steam connections cast into it, which will need to be machined and threaded. So the whole frame casting is set up in the big Hercus lathe, and the tool set at an angle to clear the rest of the frame.
Machining the connection down to diameter to take an M6x1 thread.
Threading with a die by hand.
Facing the ends.
To machine the other connection, I clamped the 4-jaw chuck from the Sieg lathe in the Hercus by the recess which centres the chuck to its backplate, and then clamped the frame in it with one jaw removed for clearence.
Machining underway.
Both steam connections done. Please excuse the lens cap cord dangling in the shot.
When I was assembling the engine, I realised the crank web needed a grubscrew to hold it. So I set it up in the Sieg lathe to drill the hole.
Starting with a centre drill.
Drilling right through.
Tapping the hole.
Here's what the engine looks like now.(except the steam connections are not threaded in these shots.) All that's left to do is the porting and possibly a bit of lapping. I'm not sure how to do the ports in the cylinder. They need to be drilled at an angle so they will emerge right at the ends. As far as I know, these castings are no longer available, so I want to get it right.
Here are some more shots of the crankshaft being made:
To ensure the crankshaft runs freely, I decided to lap it to the bearing with toothpaste.
The next shots show the making of the crank web.
Finished except for the crankpin.
A quick shot showing how I wound the spring.
Now, back to the stuff I haven't covered yet.
Turning the flywheel down for a belt groove.
Machining a recess into one face.
The flywheel is then set up in the Sieg lathe's milling attachment to put a hole in for a grubscrew.
Starting the hole with a centre drill.
Drilling the required diameter.
The engine frame has two steam connections cast into it, which will need to be machined and threaded. So the whole frame casting is set up in the big Hercus lathe, and the tool set at an angle to clear the rest of the frame.
Machining the connection down to diameter to take an M6x1 thread.
Threading with a die by hand.
Facing the ends.
To machine the other connection, I clamped the 4-jaw chuck from the Sieg lathe in the Hercus by the recess which centres the chuck to its backplate, and then clamped the frame in it with one jaw removed for clearence.
Machining underway.
Both steam connections done. Please excuse the lens cap cord dangling in the shot.
When I was assembling the engine, I realised the crank web needed a grubscrew to hold it. So I set it up in the Sieg lathe to drill the hole.
Starting with a centre drill.
Drilling right through.
Tapping the hole.
Here's what the engine looks like now.(except the steam connections are not threaded in these shots.) All that's left to do is the porting and possibly a bit of lapping. I'm not sure how to do the ports in the cylinder. They need to be drilled at an angle so they will emerge right at the ends. As far as I know, these castings are no longer available, so I want to get it right.
fcheslop
Well-Known Member
Hi Kaleb,try using a drill jig to do the ports I will see if iv got any pics
best wishes Frazer
best wishes Frazer
fcheslop
Well-Known Member
Hi again,the jig is made from a bit of scrap and drilled to the port layout for youre engine.Hope this is of some use
best wishes frazer
best wishes frazer
rhankey
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As with most machining operations, the reality isn't as difficult as you imagine it to be.
I made a couple of the current version of the Stuart oscillators last summer prior to getting my mill. I used a dremil drill mounted in a mini drill press table. I started each hole perpendicular to the face, going in perhaps 1/32" to create a little divvot. Then I very carefully clamped the cylinder in a machinist clamp at correct angle, and drilled the hole at the angle through to the cylinder using the pilot hole to prevent the drill bit from wandering. Both cylinders came out perfectly. As an alternative, you could make an angle block out of piece of scrap wood to help hold the cylinder at the correct angle. But either way, start the pilot holes perpendicular else the bit will likely wander.
The 4 port holss you had to drill in the base are a lot trickier. With the current the Stuart oscillators, there was very little margin for error, else you would end up with holes seeing daylight where they shouldn't or not connecting with cross holes where they should.
Robin
I made a couple of the current version of the Stuart oscillators last summer prior to getting my mill. I used a dremil drill mounted in a mini drill press table. I started each hole perpendicular to the face, going in perhaps 1/32" to create a little divvot. Then I very carefully clamped the cylinder in a machinist clamp at correct angle, and drilled the hole at the angle through to the cylinder using the pilot hole to prevent the drill bit from wandering. Both cylinders came out perfectly. As an alternative, you could make an angle block out of piece of scrap wood to help hold the cylinder at the correct angle. But either way, start the pilot holes perpendicular else the bit will likely wander.
The 4 port holss you had to drill in the base are a lot trickier. With the current the Stuart oscillators, there was very little margin for error, else you would end up with holes seeing daylight where they shouldn't or not connecting with cross holes where they should.
Robin
Kaleb
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Well, it's a runner. Yes, I have made a video, but first, some coverage of the final stages of the build.
To drill the ports in the cylinder, I cut a piece of wood on a mitre saw so the cylinder would be held at the correct angle when clamped.
The cylinder and angle block were then set up in the Sieg lathe with its milling attachment to start the holes.
Starting one of the ports with a centre drill.
The cylinder was then clamped in a larger machine vice and the ports drilled right through on my trusty(albeit rickety) drill press.
To make the porting jig, I decided to make a makeshift transfer punch out of some stainless steel shaft.
Machining the OD even.
Centre drilling to allow the workpiece to be supported by the tailstock.
Turning down to 2.5mm to match the ports. I am using a dead centre because it doesn't wobble as much.
Next, I set the compound slide to 10 degrees to machine a point.
Turning the taper until it forms a point.
Here it is finished except for an attempt to heat treat it which failed to make it any harder. That didn't matter too much since I was using it to mark soft metals like aluminium and the bronze of the castings(which I think may actually be gun metal since the finish after machining is a lot like brass.).
Finally comes the porting in the frame. I decided to start with the two holes that run vertically to carry steam or air to the ports themselves. So the frame was set up in the Sieg lathe with the milling attachment like so.
Once again, the holes are started with a centre drill to ensure they are in the right spot.
The centre drill is then replaced with a conventional 2.5mm drill bit to finish the hole.
Drilling the hole to depth.
Next were the holes through the threaded steam connections. I had to try a couple of different setups before I was happy to go ahead with this stage.
Drilling each of the connections in turn.
To drill the ports themselves, I made a porting jig from a piece of aluminium plate which I drilled with the correct layout in relation to the trunnion with a line scribed through the centre. The jig is moved so that the centre line points to the crankpin at mid-stroke. The punch was then used to mark the positions of these holes.
The frame was once again set up in the Sieg lathe and milling attachment to drill the ports. It took several attempts to get all the holes to actually meet, I had to solder up some that went through when they shouldn't, and I even got a drill bit in my finger at one stage! Nevertheless, I got there in the end.
And here's the video of the engine running on air:
http://www.flickr.com/photos/65997274@N02/6839544032/
I tried to embed it, but I couldn't get it to work.
To drill the ports in the cylinder, I cut a piece of wood on a mitre saw so the cylinder would be held at the correct angle when clamped.
The cylinder and angle block were then set up in the Sieg lathe with its milling attachment to start the holes.
Starting one of the ports with a centre drill.
The cylinder was then clamped in a larger machine vice and the ports drilled right through on my trusty(albeit rickety) drill press.
To make the porting jig, I decided to make a makeshift transfer punch out of some stainless steel shaft.
Machining the OD even.
Centre drilling to allow the workpiece to be supported by the tailstock.
Turning down to 2.5mm to match the ports. I am using a dead centre because it doesn't wobble as much.
Next, I set the compound slide to 10 degrees to machine a point.
Turning the taper until it forms a point.
Here it is finished except for an attempt to heat treat it which failed to make it any harder. That didn't matter too much since I was using it to mark soft metals like aluminium and the bronze of the castings(which I think may actually be gun metal since the finish after machining is a lot like brass.).
Finally comes the porting in the frame. I decided to start with the two holes that run vertically to carry steam or air to the ports themselves. So the frame was set up in the Sieg lathe with the milling attachment like so.
Once again, the holes are started with a centre drill to ensure they are in the right spot.
The centre drill is then replaced with a conventional 2.5mm drill bit to finish the hole.
Drilling the hole to depth.
Next were the holes through the threaded steam connections. I had to try a couple of different setups before I was happy to go ahead with this stage.
Drilling each of the connections in turn.
To drill the ports themselves, I made a porting jig from a piece of aluminium plate which I drilled with the correct layout in relation to the trunnion with a line scribed through the centre. The jig is moved so that the centre line points to the crankpin at mid-stroke. The punch was then used to mark the positions of these holes.
The frame was once again set up in the Sieg lathe and milling attachment to drill the ports. It took several attempts to get all the holes to actually meet, I had to solder up some that went through when they shouldn't, and I even got a drill bit in my finger at one stage! Nevertheless, I got there in the end.
And here's the video of the engine running on air:
http://www.flickr.com/photos/65997274@N02/6839544032/
I tried to embed it, but I couldn't get it to work.
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Kaleb-
Congratulations! Thm:
-Bob
Congratulations! Thm:
-Bob
