Author Topic: Elmer's Fancy  (Read 1324 times)

Offline Kim

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Re: Elmer's Fancy
« Reply #15 on: January 24, 2025, 04:55:10 AM »
Nice progress on your new little engine!  :ThumbsUp: :popcorn:

... for me it's part of the learning curve.
Yes, it's all part of the learning curve. And that, to me, is what makes this hobby so much fun - there's always something new to learn!

Kim

Offline EricB

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Re: Elmer's Fancy
« Reply #16 on: January 24, 2025, 06:56:05 AM »
Nice progress on your new little engine!  :ThumbsUp: :popcorn:

... for me it's part of the learning curve.
Yes, it's all part of the learning curve. And that, to me, is what makes this hobby so much fun - there's always something new to learn!

Kim

Thanks for the comment. So far I'm learning how adapt the design to fix, or rather cover, my mistakes. I probably can't make interchangable parts.

Eric

Offline EricB

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Re: Elmer's Fancy
« Reply #17 on: January 24, 2025, 07:20:19 AM »
One more set of parts before quitting time today. I made the piston, a "nut" for the cylinder retaining spring, and the conecting rod. The object was to use every tool in the shed I hadn't touched yet, like the follow rest. Incidently, the Sherline follower rest will let you know if your headstock is out of alignment.

When I made the crank pin I used the closest size piece of unknown steel rod I could find and filled it down to a press fit in the crank disk. It was pretty hard to work with but does the job. The problem is now the crank pin is slightly oversize to fit the connecting rod. Once I get the steam passage drilled in the cylinder I'll need to make a custom reamer to match the crank pin diameter and enlarge the big end of the connecting rod to fit.


Offline PaulR

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Re: Elmer's Fancy
« Reply #18 on: January 24, 2025, 09:12:58 AM »
Did you use a parting tool for the oil rings in the piston? The plan I'm roughly working to calls for 0.5 x 0.5mm slots. I don't have a ready made tool that narrow so used the end of a screw-cutting tool, turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. Should have just gone with parting tool width slots instead  ;D

Offline mklotz

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Re: Elmer's Fancy
« Reply #19 on: January 24, 2025, 03:23:47 PM »
... turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. ...

Next time stop turning the piston when it's about ten or 20 thousandths larger than desired.  Cut your grooves, then finish turning the piston to size.  Those last passes on the piston will remove any burrs left from the groove cutting.
Regards, Marv
Failure is just success in progress 
That looks about right - Mediocrates

Offline EricB

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Re: Elmer's Fancy
« Reply #20 on: January 24, 2025, 05:22:16 PM »
Did you use a parting tool for the oil rings in the piston? The plan I'm roughly working to calls for 0.5 x 0.5mm slots. I don't have a ready made tool that narrow so used the end of a screw-cutting tool, turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. Should have just gone with parting tool width slots instead  ;D

I made a special tool, more like a trepanning tool, to finish the cylinder on my first engine. It's become my go to tool for brass. I angled it into the piston so only a corner makes contact, leaving the grooves "V" shaped. It doesn't leave a burr.

Eric


Offline EricB

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Re: Elmer's Fancy
« Reply #21 on: January 25, 2025, 03:05:36 AM »
Day eight.

Drilled the steam port in the cylinder and lapped the column and cylinder port faces together. After that made the first of several springs to hold the cylinder in place. This one was too heavy.

I finshed the flywheel to it's final thickness and added som decorative grooves. I ended up using the plan design as a guide. Then the set screw hole was drilled and tapped. The plan reccomends a set screw bearing on a pin to hold the flywheel in place. I made a single piece screw instead.

With the flywheel finished I had enough parts to give it a test run. Success!

The next task was permanent installation of the bearing with loctite and drill the oil hole for the crank. Seemed like an easy task on paper. The problem started when the loctite started curing before I got the bearing seated. This was followed by much adult language as I tossed all my parts bins looking for something I could use to get some clearance as I squeezed the bearing into its bore using a vise. As I said earlier the bearing was a snug fit to begin with, but I got it all the way in.

The oil hole is an angled hole into an angled surface so I plunged in with a 1/16" endmill very cafefully.

Last today I made another spring for the cylinder. It's made from 0.020" brass tension wire, which a clockmaker's product. It runs much better with the lighter spring. I'm thinking I should have polished the wire before coiling it. I might have to make another.

The only things left are shaping and polishing the outside of the cylinder and finishing the column foot.

Eric
« Last Edit: January 25, 2025, 03:18:08 AM by EricB »

Offline Admiral_dk

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Re: Elmer's Fancy
« Reply #22 on: January 25, 2025, 08:53:02 AM »
Acetone will completely dissolve just about all kinds of Super-Clue ...!
So you should be able to take the >Crank apart again ....

Sorry my bad - Locktite needs Heat to take apart  :-[

Per      :cheers:

Offline internal_fire

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Re: Elmer's Fancy
« Reply #23 on: January 25, 2025, 02:50:38 PM »
There are many types of Loctite, but a favorite strong one is 648.

The technical data sheet notes:

"For Press Fitted Assemblies, apply adhesive
thoroughly to both bond surfaces and assemble at high
press on rates
."

(Emphasis added)

In my experience the allowed time for fixing is only a couple of seconds even with a slip fit.

Lesser strength products, such as one might find in an auto parts store, will give a bit more time.

Gene

Offline mklotz

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Re: Elmer's Fancy
« Reply #24 on: January 25, 2025, 03:14:04 PM »
... The plan reccomends a set screw bearing on a pin to hold the flywheel in place. I made a single piece screw instead....

A steel setscrew can raise a burr on the shaft that makes it difficult to remove the flywheel.  A short brass rod between the screw and shaft prevents that from happening.
Regards, Marv
Failure is just success in progress 
That looks about right - Mediocrates

Offline crueby

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Re: Elmer's Fancy
« Reply #25 on: January 25, 2025, 03:30:14 PM »
Or file a flat where the set screw will be. Either way works.   :popcorn:

Offline EricB

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Re: Elmer's Fancy
« Reply #26 on: January 25, 2025, 07:37:46 PM »
... The plan reccomends a set screw bearing on a pin to hold the flywheel in place. I made a single piece screw instead....

A steel setscrew can raise a burr on the shaft that makes it difficult to remove the flywheel.  A short brass rod between the screw and shaft prevents that from happening.

I get that. I don't think I'll have that problem. The shaft is drill rod and the screw is 12L14, and I rounded the end. I don't think I can put enough torque on the slotted screw to raise a burr. I have had that problem with allen set screws though.

Eric

Offline EricB

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Re: Elmer's Fancy
« Reply #27 on: January 25, 2025, 10:23:49 PM »
Day nine, final machining.

I decided to follow the plan design for the outside of the cylinder as well, so I needed a way to hold the part while I knocked off the outside corners. After considering and discarding various ways of using the mill vice, I opted for an expanding mandrel held in a 4-jaw on a rotary table. I already had most of the mandrel completed already in the soldering fixture I use for the cylinder pivot pin. Starting with that I drilled it through, from the big end, for a 10-32 tap. I followed that with a clearance drill for the OD of the tap I was using. The tap I have was too short to reach the working end of the mandrel, and I needed to get at least half way though the working end. After that it was slotted, cleaned up, and ready to use. I had to borrow a longer machine screw from one of my other tools to expand it, and that was accessed from the spindle side of the chuck.

First up was a test with the column foot. I had wanted to put a better bevel on the edge so now was the time. After dialing it in it worked like a charm. I didn't want to fix the foot to the column with loctite, I may want to replace it with a steel part later, so I used a little too much superglue that I'll need to clean up.

On to the cylinder, dialed it in using the turned boss at the bottom. On the mill I had to align the back side perpendicular to the spindle axis before making the cuts. Again it worked fantastic.

I'll post a video of it running after I clean it up and polish the brass parts.

Eric


Offline PaulR

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Re: Elmer's Fancy
« Reply #28 on: January 26, 2025, 06:56:03 AM »
... turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. ...

Next time stop turning the piston when it's about ten or 20 thousandths larger than desired.  Cut your grooves, then finish turning the piston to size.  Those last passes on the piston will remove any burrs left from the groove cutting.
Thank you, why didn't I think of that?  :facepalm:

Offline PaulR

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Re: Elmer's Fancy
« Reply #29 on: January 26, 2025, 06:58:47 AM »
Did you use a parting tool for the oil rings in the piston? The plan I'm roughly working to calls for 0.5 x 0.5mm slots. I don't have a ready made tool that narrow so used the end of a screw-cutting tool, turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. Should have just gone with parting tool width slots instead  ;D

I made a special tool, more like a trepanning tool, to finish the cylinder on my first engine. It's become my go to tool for brass. I angled it into the piston so only a corner makes contact, leaving the grooves "V" shaped. It doesn't leave a burr.
Thanks for the pic. That's what I was aiming for with the pointed tool I used but it probably didn't have suitable relief.

 

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