Building a Factory Engine, Elmer's #41 (Finished on 2-28-10)

[Metal Butcher]

#60 For today's post I'll start by making the 'rocker bearing'. The fist step was to mill an accurate block of brass, and check it for squareness.

#61 I used a 'tenths' indicator to center it in the small four jaw for drilling and reaming the 'rocker shaft' hole. In this setup I also turned the 3/16" x 7/32" cylindrical boss on the one side shown in the drawing.

#62 To mill out the 1/4" x 3/8" opening took an unsettling set up that required the use of space blocks on the opposite end of the vise to balance out jaw pressure. It would have made a much better set up to have had an additional 1/8" added to the 7/16" dimension. It would be milled off after the opening was milled out by simply flipping it over. Live and learn. :

#63 Below is the finished 'rocker bearing'. The holes are clearance drilled for 4-40 studs. I won't be using the 3-48 specified in the plans due to not having the right size material to thread or the 3-48 nuts on hand. We do what we do out of necessity.

#64 The two piece 'crosshead guides' are next. After drilling the eight 4-40 clearance holes, I took the previously milled pieces and filed off the machine marks left by the end milling.

#65 In the plans Elmer suggests three cosmetic options that can be used on these pieces. Leave them plain, drill 5 spaced holes, or mill out an arch. Unfortunately there are no details like the dimensions, drill size, spacing etc.

I calculated for an 'arch' milled from the top down with the piece up side down in the vise. The machine moves are; one cut with a 1/4" ball end mill set to a depth half the height of the work piece using the "Y" axis (hope I got this right). Zero out on the end and move in along the "X" axis .350" for the first cut, and 1.710" for the second cut using the "Y" table movement. Switch to a regular square 1/4" end mill, set to the same depth and cut with one pass at.475" and 1.585" using the "Y" table movement. Finish up by cleaning out the remaining material between the last two cuts. This of course is my idea of the arch, you could shorten it a bit by adding 10 or 20 thousands to the first move on both end mill, and at the same time subtracting the same amount from the second movement of both end mills. This worked well, but I decided on using the drilled hole option on this build instead.

I decided to try five equally spaced 1/4" reamed holes. The work pieces were stacked laying on their sides in the mills vise. Why do all of this twice. After zeroing out on the outer edge, the table was moved along the "X" axis to .350", .690", 1.030", 1.370", and 1.710". At each location I center drilled, drilled, and reamed before moving to the next stop (location).

#66 After d-burring the holes by hand using a countersink, a light sanding with 600 grit sand paper,the parts are finished.

#67 The rest of this post is about how I made the 'connecting rod'. I feel proud of the new method I used today to create its tapered portion. On an rectangle of brass I laid out all the dimensions for tuning, and the locations of the 3/16" hole for the 'crank screw', and the 1/16" hole for the 'piston rod' pivot pin. After drilling and reaming the holes I centered it in the for jaw. I center drilled the end for a live tail stock center, and brought it out towards the tail stock end, leaving only a 1/2" the extra 3/4" of material on the chuck end in the chuck. The blank was originally cut one inch longer. A quarter of an inch was designated for cut off at the tail stock end, and the remaining three quarters of an inch allocated to the chuck end.

#68 Below is the first diameter of 5/16" cut all the way from the tail stock end to the chuck end, past the cut-off point at the chuck.

#69 The second .250" diameter was cut all the way from the tail stock to the scribed line designating the start of the boss on the crank screw end.

#70 The third diameter was cut at .170" between the two boss ends, (not shown in picture). I stopped the cut at the chuck end and brought my carriage mounted traveling rod forward and compressed the head stock mounted 1" dial indicator to the 1" mark. After moving the carriage .100" towards the tail stock I stopped and moved the cutter in .001". Again I moved the carriage .100" towards the tail stock and stopped to move the cutter in .001". I did this twenty times to create a gradual taper. It worked like a charm, typing this description up was harder, and took much longer. You can barely see the gradual steps in the picture below.

#71 Using the same tapered cutter I trimmed the out side ends to leaving just a small diameter for support. Using a file the steps were carefully blended away. After wards I used an Exacto saw on the small end after backing off the tail stock just a little but still offering support, and used a parting tool for cut-off on the chuck end.

Prior to filling, (I normally don't file on the lathe) as a safety precaution I wrapped the outer end of the chuck with a double layer of Duct Tape and rolled it over the chucks jaws. I'm right handed and my left forearm is an inch or so from the sharp edges of the spinning chuck. It took only one minute to put it on and to take it off, why should I take any chances.

#72 And there it is all finished up. I think it turned out very well, and I'm pleased.

#73 I enjoyed making it soooo much that I made a second one with a few minor changes. I made the boss on the crank end a little shorter, and reduced the second diameter on the pin end along with making it just a tad shorter. The hole spacing is identical and the two are interchangeable.

I always sleep well after a GOOD day in the shop. :big:

-MB

 

[1hand]

And now I know how to taper. Thm:

They turned out real nice Rick. I figured you moved the tailstock over til I read the post.

Matt

 

[1hand]

I just noticed..............Where the penny go? I see a shinny piece of brass in its place.

 

[Metal Butcher]

I just noticed..............Where the penny go? I see a shinny piece of brass in its place.

Well Matt, its been a tough year for me financially....Just kidding! :big:

The 'penny' is on the larger 6" chuck. The milled out area on the 4" chuck used in the post is to small for a penny so I machined up a brass disc to fill the void.

Thanks for the compliment in your previos reply. I was busy cooking and eating while you posted it. I had to wing it. 'Honey" said "Your on your own". She's busy lounging around, its Friday for her! Gee... I wish I had a weekend off! I better shut up before I get my butt in a sling.

HEY! I want details on you new torch. It looks like what I need instead of the clunky old Berzomatic of mine.

-MB

 

[zeeprogrammer]

Those are nice looking connecting rods.

I've been enjoying the detail in this thread. Looking forward to seeing the engine.

 

[1hand]

Its a Smith Little Torch. It runs off of the disposeable bottles. Right now I'm going to use MAP gas and Oxygen.
It came with #1, 2, 3, 4, 5, 6, 7, straight tips and a rose bud heating tip, and also a duel flame #6 "which is really cool". It came with the regulators that screw right on the disposeable bottles and they are preset. Holding it is like holding a pencil. It also came with the magnetic base and tip holder.


I'm not much of a one handed video guy, but this should give ya an idea of the size, and flame capability's.
I can delete this after you view it if you want.
Matt

 

[Deanofid]

Those rods look really good, Rick. It'd be hard to pick a favorite, they're both so nice.
I've made rods with a similar shape, but used the tailstock to set over. You probably had both these done before I even got my TS dialed back into zero. Good job, there.


I see you have decorated your Chi-chucks a bit. I have one too, and got annoyed with the hole they put there for the no-name. I didn't have a penny..
Apologies for the semi O.T.

Dean

 

[Metal Butcher]

Its a Smith Little Torch. It runs off of the disposeable bottles. Right now I'm going to use MAP gas and Oxygen.
It came with #1, 2, 3, 4, 5, 6, 7, straight tips and a rose bud heating tip, and also a duel flame #6 "which is really cool". It came with the regulators that screw right on the disposeable bottles and they are preset. Holding it is like holding a pencil. It also came with the magnetic base and tip holder.

I'm not much of a one handed video guy, but this should give ya an idea of the size, and flame capability's.
I can delete this after you view it if you want.
Matt

Don't "delete" anything!

Thanks for the great demo video. It really helps a lot. what a great outfit!

I need your reply information as a future reference. It'll save me a frustrating search for when I decide to buy an outfit. The light weight look of your outfit is a real plus over a bulky tank. I heard you cant get the slender propane tanks any more?

Rose bud tip? Might be a good selling point to use on "Honey". Lots of rose plants around here! :big:

-MB

I use a tripod on occasion to steady my hand on still shots, and you've seen my shaky videos, I'm sure.

 

[Metal Butcher]

HI dean. I offset the tail stock once. It was a bear to get it right again.The way I did it was quick, very quick! I think George B's build posts subconsciously gave me the idea to use the "step off method". If that's what I actually did. The idea just popped into my head after I cut the third diameter. Very strange if you ask me.

Yea that "hole" annoyed me the minute I saw it. I never got a good look at the brand name on you chuck. Now that I see it, I like it! They try to glue the labels over oil at the factory as far as I can tell. Most if the imports arrive nameless. How sad is that. We need to come up with a supplier that owns a pair of calipers, and sells small Chinese coins! Maybe E-Bay?

No need to apologize. But what is a "semi QT/Ot"? I need a new monitor and a new pair of glasses. Actually, I need a whole new computter. This thing is a 15 years old pile of scrap with leaky capacitors.

-MB

 

[Metal Butcher]

Those are nice looking connecting rods.

I've been enjoying the detail in this thread. Looking forward to seeing the engine.

Thanks Zee! Where you been hidein.

I'm lookin forward to you next build.

Soon I hope.

-MB

 

[Deanofid]

Semi OT; Half a bubble off topic.
Sorry for apologizing.

Keep that on the qt, ok?

Dean

 

[mklotz]

If you don't want to offset your tailstock (Who does?), mount your boring head in the tailstock and make a center to fit one of the holes in the head.

 

[Metal Butcher]

If you don't want to offset your tailstock (Who does?), mount your boring head in the tailstock and make a center to fit one of the holes in the head.

Hi Marv. That's a darn good suggestion, and I'm sure someone out there isn't aware of this method. I think the use of a boring head for this purpose would be about the same amount of work as offsetting, and re-setting the tailstock. Both require basically the same procedures. However, others may disagree. I used the step-off method rather as a learning experience, than an avoidance of manipulating the tailstock to create the tapered section on my piston rod.
My reply saying that lining up a tail stock is a "bear" was simply in agreement with Dean's comment, and not the reason for using the step off method.

The calculations needed to create the taper using the step off method were simple enough for me to accomplish the goal.

Again, thanks for your usual informative contribution Marv.

-MB

 

[mklotz]

MB,

My suggestion wasn't meant to disparage the approach you used. I hope you understand that. In fact, I've used your technique numerous times.

I posted what I did to alert lurkers and future readers of this post to the fact that there are other ways to generate a long taper than the dreaded TS offset. Brian seems to have picked up on the idea and run with it so others will be exposed to it in his post as well.

BTW, let me point out that this idea is hardly original with me. I've seen it suggested by numerous people on other fora.

 

[JMI]

The thread is providing numerous tips and techniques that I shall find very useful in the future.
Nice piece of work, MB.

Jim

 

[Metal Butcher]

#74 Hi all. A few days have gone by, and its time to post my progress. In the picture below are the 'spacers', I made an extra one because if I didn't, one will get dropped and lost for sure. These need to be the same height, and I chose their height to be .0005 more than the thickness of the 'crosshead'. I lapped them to within .0001 of each other.

#75 To machine the 'eccentric' I started with turning down the outer diameter to 5/8", followed by drilling and reaming the crank shaft hole. This was done in one set up to assure the bore would be concentric with the outer diameter. The workpiece was transferred to the four jaw independent jaw chuck and centered with the use of a dial indicator. With the valve travel set at .100" the workpiece was set over .050" to turn the 7/16" diameter 3/16" long. Of course this could all be done using a four jaw chuck alone.

#76 Since I have very little experience turning eccentrics, I took the opportunity to practice and machined up two more. The plans call for the use of a 3-48 set screw. I don't have any on hand, but I do have a whole box of 100 5-40's. With plenty of room on the eccentric, I couldn't find any reason not to use them.

#77 The 'rocker shaft' assembly requires two rods, a short 1/16" diameter to connect the 'valve rod' with the 'eccentric strap', and its 3/32" pivot rod. Both rods are cross drilled with a #70 drill bit to accept a thin copper retaining wire. I drilled the 1/16" pin without a problem, but it took seven try's to get the 3/32" rod drilled on center. I just kept trimming off the drilled end from a longer piece till I got it right.

#78 And there's the finished 'rocker shaft' assembly being test fitted in the 'rocker bearing'. The two rods on the 'rocker shaft' "assembly" were a good snug fit assembled with Loctite.

#79 The first step in making the 'crank' disc was to turn the O.D. to 1-3/16". Then the out board side was faced, followed by drilling and reaming the 'shaft' hole. I added .005" to the cut-off length to allow for a later finish facing of the inboard side. This will be done with the assembled 'shaft' held in a collet. It seems that I never get an acceptable finish from parting with a cut-off blade.
I'll get back to the 'crank' a little later in the post.

#80 The part being made below is my version of a replacement for the 'crank screw' shown in the original drawings. I don't care for the very small shoulder support the 'crank screw' offers. Apparently Elmer added a nut on the opposite side to add a little more stability. But, with all do respect to Elmer, I feel this nut is counter productive by applying force in the opposite direction of the threaded screw. And from what I understand this is not a good engineering practice. In my opinion the flanged bushing shown below is a better idea. It's pulled up tight in one direction against the 'crank' disc making it a good solid assembly, and with a more adequate shoulder surface for this application. The bushing is clearance drilled for a 4-40 screw or bolt of choice.

#81 I did a little practice machining on this part too. I wanted to see if I could make four identical and interchangeable pieces.

#82 In this picture the hole for the crank pin/flange is being drilled and tapped 4-40 with a .500" offset. I bolted the crank disc down flat on a fixture plate to assure that the tapped hole is parallel with the shaft bore, and perpendicular to its face.

#83 The picture below shows some trials using slightly different milling cuts to see which I thought would look the best. I think that either of the two lower ones will do. Its also nice to practice, and to have a few spares on hand.

That concludes today's progress report. I hope you found it interesting.

-MB

 

[1hand]

Nice job indeed Rick. Could you explain lapped or lapping to me. I see it mentioned all the time, but don't really know how it its done.

Hope its not too stupid of a question?

Matt

 

[Metal Butcher]

Nice job indeed Rick. Could you explain lapped or lapping to me. I see it mentioned all the time, but don't really know how it its done.

Hope its not too stupid of a question?

Matt

There are no stupid questions, only stupid answers!

Parts like a piston and cylinder can be lapped together (using an abrasive) to make them fit smoother, and also to reduce a diameter or to increase an opening size. IE. Lapped together.

The parts I lapped were reduced in size to match each other. Its a abrasive process using a lapping disc or plate (like cast iron) charged (Coated) with an imbeded abrasive. A part can be held stationary while the lap spins, or the lap can be stationary while the part is spun of pushed back and forth across the surface. Using sand paper on a smooth flat plate of glass can be considered lapping if the process is used for minor dimensional adjustment or leveling.

1. To polish (a surface) until smooth.
2. To hone (two mating parts) against each other until closely fitted.

Lapping.

-MB

 

[1hand]

Thanks, I imagine there is "lapping compounds" and such available?

Did you use a plate of glass to manually rub the spacers against, to achieve such close tolerance?

Then I suppose that handy dandy granite check stand I just picked up will come into use. To see how much more rubbing you need to do.

 

[Metal Butcher]

Thanks, I imagine there is "lapping compounds" and such available?

Did you use a plate of glass to manually rub the spacers against, to achieve such close tolerance?

Then I suppose that handy dandy granite check stand I just picked up will come into use. To see how much more rubbing you need to do.

Yes. That's the way I lapped them individually to dimension.
After a swipe or two, the part is checked with a tenths micrometer.
Its a slow process but good way make a final adjustment to a part for various reasons. You need a true flat surface like a lapping plate or a glass plate. 1200 grit wet or dry paper does a good job if your goal is a supper smooth surface, and a higher grit will make dimensional changes a bit faster if the smoothness is not a factor. A 'lap' can also achieve similar results if its less that perfect by moving it around to remove material equally and to level high spots, such as a copper or even wood. There's probably a complete book out there that covers the subject to a depth that would give most of us a headache. I know just enough about it to get by with an occasional lapping that works well enough for my purposes. And yes there are many grits of lapping compound out there. Some of the compounds need to be used with caution. They can wear out and destroy a fit in good order, like real fast. I use the compound rarely, and only as a last resort or a quick fix. Some of the members here are very capable and experienced with its use, and fine tune their fits on a regular basis. I occasionally lap a piston to bore fit using a fine metal polishing compound that breaks down quickly and won't cause any harm. I hardly consider it a proper lapping but it does smooth out any small high spots.

-MB
spots.