Bogstandards "Paddleducks" engine

[Blogwitch]

Shred,

You are doing a wonderful job.

You have the crossheads done, they are the hardest pieces to make, the only other critical bit is the control valve. So now you have this bit done, the rest should be plain sailing.

Blogs

 

[Paolo]

A really wonderful Job.... :bow:
Paolo

 

[shred]

Made four little square blocks of brass for the bearing blocks today. Gave me something useful to do whilst on a two hour conference call with Asia that I only needed to be involved with occasionally (since I have to talk, it means I have to turn off the machines, making a nice safety interlock)

The next bit of thinking revolves around de-metrification; contributions and idle thoughts welcome--

Originally I thought to have the main crank shaft be 1/4" drill rod, but looking at the little raw bearing blocks (for some reason whenever I work in metric my mental image of the parts-to-be-made is always about 25% too large) it seems that 3/16" would be a better fit to the originally spec-ed 5mm (those are my options-- 1/4" and 3/16", so the big end pins will likely be 3/16" as well)

I don't think that matters much except looking at the eccentrics, the crank bore would be very close to the eccentric strap with a 1/4" shaft. But that eccentric strap is 14mm and I'm not likely to make 14mm eccentric straps unless I have to. 1/2" (12.7mm) and possibly 9/16 (14.3mm) are far more likely to be in my drill repertoire. Of course if I do that, then I may have to redo the eccentric geometry because I suspect it may throw the throw out.

Hmm.. now I get to think on which is easier, boring the holes or redoing the eccentrics? Time to go see if Marv has an eccentric-strap design program

 

[shred]

Got the bearing blocks cranked out of the squared blocks I made yesterday and a start on the baseplate.

About halfway through I remembered the camera was now charged.

Here's a decorative contour pass after drilling, reaming and tapping (#2-56) the blocks. Not for nothing does it slightly resemble the Alamo
Note the vice stop. Most handy when doing 4 sets of bearing blocks. Zero the DRO on it and the fixed jaw and it really helps speed things along. In this case I just set the corner rounding bit where I wanted it once and kept putting blocks in the stop, cut, flip and cut again.

Over to the lathe and being bolted onto a headless #10-32 bolt for the boss cut (3/16" crankshaft ~= #10 bolt)

If you lock everything but the cross-slide down, and set the infeed once with the compound you can crank 'em all out quickly if you were reasonably careful with the width (I used 3/8" material which worked nicely as a just-under 10mm width) -- just bolt them on, face to the nut, flip, face to the nut and go get the next one.

​

After checking that the crank bore is in the right spot, it's time to make the baseplate. There is an important lesson here for those inclined to take shortcuts. This is the fourth baseplate of the night.

Here's the story-- Since I'm using the vice stop and DRO, I re-marked Bogs baseplate drawing to be origin in one corner instead of the datum line on center as he had it so I can just drive the DRO to the coordinates without fussing around marking-out. I have a decent stash of irregular 1/8" Alu sheet, so I grabbed some and hacked off a bit (plate #1). Squared up the rough cuts and aw, rats.. I overcut it squaring... it's 99mm long.. 1mm too short. Well, I could probably use it as-is, but I have a lot of Al and it didn't take long to get to this point, and I'd like to do it right, so off to the bandsaw.. since the first plate is just a little small, slap it in a clean area of the Al sheet and draw around it with a marker to get a cut line. Cut slightly outside the lines to be sure I have enough for squaring. (plate #2). Square that up all nice and neat, 50mm x 100mm. Stick a spotting drill in the mill and away we go spotting the hole locations. Drive Y to 5mm and run along X along spotting them as needed. 5mm.. 15mm.. Third location out and I spot somewhere that's not supposed to have a hole as I'm going off the X and Y at the sides of the drawing and that particular X is for another row. Crud. Well, it's on the edge, I can use it as an extra support bolt. All I have to do is remember to drill one over on the other side as well. Keep going. 45mm.. <spot>... 99mm...<spot> 105mm... <erk, wait.. one hundred and what?!?> This plate is 100mm long. Look at the drawing again. Plain as day, it's 50mm x 110mm. Aw Cr@p. Time to go cut some more stock. Since we're a little torqued with ourselves today, slap down the old one in some of the now-diminishing available sheet, outline it and cut it out... (plate #3) to realize immediately that we forgot to add the 10mm to the length. Son of a... one more time, but this time with plenty of extra rough (plate #4), and for good measure, we'll actually mark it out this time. And mark where the holes aren't supposed to go.. This time, so far, It's a success.

So now you know "the rest of the story"

No way I'm going to try cutting the crank clearance slots in the baseplate tonight..

 

[Kermit]

:big: HAHA Cut it twice and it was STILL to short! :big:


That's never happened to ME. (Everyone ducks for cover and eyeballs the sky for lightning bolts)

 

[Shopguy]

Coming along very well. Excellent photos of showing making the pillow block bearings. 8)
Regards
Ernie J

 

[Maryak]

Shred,

Your engine is coming along very nicely. :bow: :bow:

Your recycle box is doing the same as mine, recycling the recycled. ;D

Best Regards
Bob

 

[shred]

Yeah, I made two nicely squared pieces and one rough chunk for the scrap, er, "small aluminum pieces" box . The squared ones will likely get used before long-- too easy to clamp them up and hack away for some little task. Maybe if I get really bored someday I should go through the scrap boxes and square off the really baroque bits and pieces...

Frank Ford has a piece on his web site about putting a hole through nub ends of lathe stock to use as general purpose spacers. Over time I've faced off and drilled a handful of short-ends in standard small-tap shank sizes to make handy little tapping blocks that can be easily modified for special purposes.

 

[bentprop]

I feel your pain,shred.I've done exactly the same thing,but with the top plate
I've put the whole thing aside until I either get better at making stuff,or kick the bucket and some other poor slob gets to puzzle over my cock-ups,eeerrrrr,modifications :big:
regards,Hans.

 

[shred]

Got the slots for the cranks cut without excess drama, after a couple rounds of cut-and-try, though I did notice one glitch when I was editing the photos that will get fixed.

The reason for the mass amounts of Dykem on the blocks is I thought to bolt the blocks down, hose down the assembly with spray layout fluid, wait for it to dry and cut to the white spaces. That didn't work as well as I hoped. Too much flaking and oozing around and under the blocks.

If you do these with a DRO, keep a pad of paper and pencil handy to write down what coordinates you're working on and getting back to.

 

[Kermit]

I assume you mean the little wave up near a corner of your cutouts?

;D I've heard this before and been eyeballed as some kind of saboteur by the machinists at work. "That wasn't there when I gave this to you".



Damn my eyes, 8)
Kermit

 

[shred]

I assume you mean the little wave up near a corner of your cutouts?

;D I've heard this before and been eyeballed as some kind of saboteur by the machinists at work. "That wasn't there when I gave this to you".



Damn my eyes, 8)
Kermit

Yeah, that was on the side that was towards me in the vice and I must have missed running the mill all the way from side to side when I deepend that end. As I remember there was some debate in my mind as to if I was going to 37mm or 37.5mm for that particular space. Another reason two keep good notes while you're working!

 

[shred]

Spent most of the day playing outside, but got the flywheel done (and fixed the mis-cut).

One more good use for the vice stop and DRO (and you don't even need the DRO)-- since it's zeroed on the fixed jaw and edge of the stop, its easy to find TDC to drill the set screw hole.

Measure the flywheel width and thickness, set it on parallels against the stop so the widest part of the wheel hits the stop, then drive over to half the width and half the thickness, spot, drill and tap.

 

[Kermit]

???&#160; How do you account for the thickness of the drill bit itself?

If you touch at the edge then go over to the center isn't the radius of the drill bit going to cause you to move over too far?

Expecting to feel stupid soon,
Kermit

 

[shred]

??? How do you account for the thickness of the drill bit itself?

If you touch at the edge then go over to the center isn't the radius of the drill bit going to cause you to move over too far?

Expecting to feel stupid soon,
Kermit

This may not be the best way, but it's what I learned playing with CNC machines-- I zeroed with an edge-finder such that the spindle center is at 0,0. Drilling is then dial-and-drill since the center of the hole is the hole coordinates.

I apply cutter size offsets for milling. That's sort of a nuisance with imperial cutters and metric measurements, but makes sense in my brain and isn't too bad with a shop calculator handy-- want a cut 5mm from the stop-edge? Drive the DRO over to (5mm + cutter radius) and make the cut. The same thing can be done with handwheels, but it takes a little more care and a lot more calculatoring if you've got imperial dials and are making metric parts.

 

[Kermit]

I zeroed with an edge-finder such that the spindle center is at 0,0. Drilling is then dial-and-drill since the center of the hole is the hole coordinates.

Don't understand a word of it. ??? (Kermit leaves for google book land in order to add this piece of appearantly much needed know how to his "pile" of pdf files)


Thanks Shred. "I'll be back!"

 

[Metal Butcher]

Kermi, Its just a simple "wording malfunction." I breezed through using my secret speed reading method and understood completely.

My understanding: You simply zero out the dials and the spindle- center on the x-y edges of the work piece using a standard edge finding practice. Then you move in from both directions half the thickness and diameter of the work piece to find dead center. Then you drill or what ever at ground zero or 0,0 or the sweet spot, or home, or whatever you call it.

(When at that point I usually take a five second break to dance the Chubby Checker "Twist" before proceeding. Its help to sooth me and results in good accurate drilled holes. Don't laugh, try it some time).

Shred, you aptly named it, "Dial- and- Drill."

I like it!

-MB

 

[shred]

Kermi, Its just a simple "wording malfunction." I breezed through using my secret speed reading method and understood completely.

My understanding: You simply zero out the dials and the spindle- center on the x-y edges of the work piece using a standard edge finding practice. Then you move in from both directions half the thickness and diameter of the work piece to find dead center. Then you drill or what ever at ground zero or 0,0 or the sweet spot, or home, or whatever you call it.

When at that point I usually take a five second break to dance the Chubby Checker "Twist" before proceeding. Its help to sooth me and results in a good accurate drilled holes. Don't laugh, try it some time.

Shred, you aptly named it, "Dial- and- Drill."

I like it!

-MB

That's correct. If I had a laser beam directly down the spindle, it would be exactly in the corner of the stop and vise jaw when the DRO says X=0 and Y=0. If I had a 3/8" cutter in the spindle and lowered the quill, it would cut a 3/8" hole centered on 0,0 (which would take a semi-circle notch out of both the vise jaw and the stop, so I avoid that).

Drill holes are generally specified to the center of the hole and thus the center of the drill, so working off the center of the spindle works well-- no correction needed.

For side-milling to a dimension, you work with the side of the cutter, so you really want to know where it's edge is. You can zero off that, but that's kind of a pain since your zero is only good for the side of the cutter you zeroed on-- if you touched off on the right side of the cutter for example and then wanted to cut on the left side, you have to either touch off again or apply a correction. I just leave the spindle zeroed on the center and correct for all the sides. That way you can change cutters with abandon and not have to reset the zero, just change the 'correction-factor' you apply when milling, and that is constant for any direction you cut until you change the cutter (you do, however, need to know the cutting diameter of the cutter accurately enough to produce the desired results-- CNC machinists can get all wound up about cutter compensation, though for our kind of work usually good-enough is good enough.)

Here's a little crap-o-cad sketch that might help. The red dotted circle is a cutter zeroed on center-- a drill or end-mill, showing how for a drill hole, it cuts where it's supposed to (assume it's the appropriate size for the hole), but were I trying to mill to the 10 line, it would cut too much off.

MB: I will have to try the twist

 

[Metal Butcher]

{Shred wrote:} MB: I will have to try the twist



If you have a radio on as background, turning up the volume and taking a 5 to 10 second break before a critical operation is also beneficial.
This technique is not limited to any song or dance. "Stepping away" to have a few puffs of a good cigar, or a breath of fresh air, etc, will also work.

Drill 2 holes and call me in the morning. :big:

-MB

 

[shred]

Got a bunch done today as I had almost all day to run free in the shop.

Started out making the crankshaft webs. Got a piece of 1-1/8" hex brass and whacked it down to 28mm diameter. Then I sliced off some 6mm-or-so slices. To true them up and make them all 5mm thick, I bored out a set of soft jaws I had mounted on my Taig lathe chuck (it was handy and had soft jaws on it which are excellent for this sort of thing), faced the disks to 5mm and reamed the center hole. I had forgotten how useful that little thumb-screw carriage stop is on the Taig. Must make one for the 12x

Somewhere along the way I made a 3/16" toolmaker's reamer to help with the holes, so here's the disk stack on the reamer. It came in handy finishing the second set of holes.

The third hole is less critical, so I drilled them as a stack-- drill the top one, pull it off (otherwise it can get loose and climb the drill), then the next, remove it, next...

Reassemble the stack and mill the sides of the webs

Then two at a time on the rods for drilling and tapping #2-56 (the second web is only there to fill space so the vise stop doesn't hit the other jaw-- once the first was tapped, I flipped the set over and drilled and tapped the second web in the same location. The lower hex piece is a tapping guide that I made after seeing some of Marv's on here-- the bottom half is drilled for a small-size tap shank, the upper drilled and reamed for a 1/8" dowel pin. In use the dowel pin keeps it aligned and the guide slides down the pin as the threads are tapped. I usually turn it with my fingers on small taps.

Then back over to be slit with a slitting saw. You'll notice my saw didn't quite reach the small hole and I had to extend the cut a little with a jewelers saw. Lucky for me the ugly cuts are pretty tough to see once it's all assembled.

Then I drilled out a clearance hole for the squeeze bolt. This is where disaster struck. I had a piece of metal (broken slitting saw blade) in the cut to stop the clearance drill from breaking through beyond the cut, but it got a little out of place on one and before I could stop it, I'd put a clearance hole right through the web. Ack. Bogstandard wisely makes extra parts for reasons like this, but.. I'm lazy and didn't. So, make a new one or fix the old? May as well try and fix the old first. I scrounged up a little brass wire that fit ok and silver-soldered it into the side where the threads should go.

Cut off the excess and retap and you can't tell it was ever wrong (which means it's right ) The only way I know which was fixed is the fire scale and that will be gone soon.

Then on to the eccentrics. Since I'm not using 4mm material for the straps, I cut the slot to 3/16" which limits the available space for the set screw (mental note, make a good slotting/grooving cutter next time I have the cutter grinder going). I'll be putting in a flat-blade screwdriver #2-56 set screw later. I chose to try re-using the cut off bolt and nut from turning the bearing block bosses instead of tapping a rod as in Bog's instructions and it worked well.

Here's the crankwebs and rods and eccentrics and flywheel all test-assembled to see if it's all going to work. Amazingly enough, it all fit and turns with only a little effort. Some running in and it'll be fine.