HUNSLET QUARRY ENGINE BUILD

Where users can chronicle their builds. Start one thread and continue to add on to it.

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Fred_V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Tue Sep 01, 2015 8:38 pm

Valve gear came next. The eccentric rod ends are a casting and made in the usual way. The rod itself is made from flat stock and welded. I made a fixture to get them all the same. The 2 bolts were later replaced with flat head countersunk screws and the weld ground down.

The expansion links were waterjet cut so I had a bit of taper in the slot to file out to get them parallel. I made the die block from a piece of O1 tool steel round machined to fit the slot and then hardened. The links were hardened with Kasenit.
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ecc rod ream.JPG
expnsion links.JPG
Fred V
Pensacola, Fl.

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Fred_V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Tue Sep 01, 2015 8:48 pm

The slide bars are just CRS flat but have slots machined at the end of each stroke on the under side of the top bar to make them wear evenly.

The oilers are called "onion oilers" and were a popular item on the prototype Hunslets. I made these using form tools and a bit of sweat. The front oiler drips onto the piston rod and onto the bottom slide bar.

The plans called for the crossheads to be a simple machining job but I took them deeper and added slippers. I think it's worth the effort.
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onions finished.JPG
Fred V
Pensacola, Fl.

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Fred_V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Tue Sep 01, 2015 8:54 pm

Now for the first great experience in building an engine. RUNNING ON AIR.

I haven't figured how you guys add videos to the post so here is a link.
https://www.youtube.com/watch?v=ae3vYIo ... e=youtu.be



The second is running on steam and I hope that will be this spring.
Fred V
Pensacola, Fl.

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Fred_V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Tue Sep 01, 2015 9:11 pm

Fred_V wrote: The oilers are called "onion oilers" and were a popular item on the prototype Hunslets. I made these using form tools and a bit of sweat. The front oiler drips onto the piston rod and onto the bottom slide bar.
Here is a pic of the process to machine the hex on the oilers. I start with hex bar and then use it to index cutting the smaller hex.
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onions wrench flats.JPG
Fred V
Pensacola, Fl.

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Fred_V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Wed Sep 02, 2015 8:32 am

The next posts will be about setting the valve gear. I have moved the reverse eccentric for clarity.

The first step is to get the valve centered on the valve rod. Rotate the eccentric so that it's full stroke is pointed up and lightly snug the set screw. It doesn't matter where the crankpin is for now.

Now measure the width of the steam chest and set your caliper to 1/2 of the dimension. Adjust the valve rod to get the valve centered.
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valve 1.JPG
valve 2.JPG
Fred V
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Fred_V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Wed Sep 02, 2015 8:44 am

Next is to find front and back dead centers for the piston. I made a video of this process on a friends Allen Mogul.
https://www.youtube.com/watch?v=Bkq-lMtcv4g

You can see the punch marks on the wheel and where I split the difference to find front dead center.
Now rotate the eccentric anti clockwise to put the high spot at about 4 o-clock. At this position the valve should be just cracked open or right on the port edge. Snug the set screw.
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valve 3.JPG
valve 4.JPG
Fred V
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Fred_V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Wed Sep 02, 2015 8:53 am

Now rotate the driver to back dead center. The valve should be just on the line of the rear port. If it is not then adjust the valve rod to take up half the difference of where it is and where you want it. Go back to front center and check there. You may have to make adjustments several times to get the valve perfectly even front and back and adjust the eccentric again to put the valve on the port line.

For an engine with outside steam chests a rocker arm reverses the valve motion so at front center the eccentric will be set as shown here for back center on the Hunslet.

Now set the reverse eccentric at about the 2 o-clock position and repeat the whole procedure but now rotate the driver in reverse.
Easy!!?
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valve 5.JPG
Fred V
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Fred_V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Thu Sep 10, 2015 8:11 am

The castings came with a nice brass casting for the stack cap and an iron one for the base. Lots of swarf before finishing that cap. It jumped out of the chuck at one point so I made a support for the tailstock.
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stack.JPG
stack2.JPG
Fred V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Thu Sep 10, 2015 8:24 am

The safety valves were a fun project. I had some 1 1/2" naval brass hex on hand so I used it (wish it had been 1 1/4"). I used the big hex to index and machine the finished size hex.

The body was just a lot of turning and a couple of form tools to grind. There is a trick to make these valves pop. You need to make a shoulder around the valve or ball to get it to lift quickly. The spring was sized based on the seat area X pressure. I've yet to test it on steam but will soon and will report back.
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safeties finished.JPG
safeties4.JPG
safety internals.JPG
Fred V
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John_S
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Re: HUNSLET QUARRY ENGINE BUILD

Post by John_S » Thu Sep 10, 2015 5:08 pm

Fred_V wrote:The safety valves were a fun project. I had some 1 1/2" naval brass hex on hand so I used it (wish it had been 1 1/4"). I used the big hex to index and machine the finished size hex.

The body was just a lot of turning and a couple of form tools to grind. There is a trick to make these valves pop. You need to make a shoulder around the valve or ball to get it to lift quickly. The spring was sized based on the seat area X pressure. I've yet to test it on steam but will soon and will report back.
That's great Fred! I'd love to have a drawing of the internals of those if possible.

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Fred_V
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Re: HUNSLET QUARRY ENGINE BUILD

Post by Fred_V » Thu Sep 10, 2015 5:35 pm

Here is the basic drawing. The seat is 3/8" dia. This engine is a 4" scale so this is WAY bigger than normal.
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Screen Shot 2015-09-10 at 5.32.41 PM.png
Fred V
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kvom
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Re: HUNSLET QUARRY ENGINE BUILD

Post by kvom » Fri Sep 11, 2015 6:50 am

Are you going to bring the chassis to CSP&P meet? Would love to see it "in person".

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