Kiwi Mk2 Engine

[vcutajar]

This morning I was thinking of drilling the oil passageways in the crank but as I know that I work slowly and this afternoon I have to go to work I decided not to do the passageways.

I wanted to do something simple and decided to do the hole for the breather assembly in the rear crankcase. Marked the hole, fixed the casting to the angle plate and drilled and tapped for 6mm fine. As the surface in the area is round and tapered, I counterbored with an endmill 10mm so that the body of the breather will seat on a flat surface. Et voila finished. At least I did something today. This maching thing has become addictive. I need to do something, even if I sit down in front of the plans and plan something, at least I will not get withdrawal symptoms.

 

[steamer]

Looks good from here! It's a fatal disease and there is no known cure...... ;D

Dave

 

[vcutajar]

Thanks Dave.

Started work on the four oil passageways holes in the crank but only managed to finish three of them.

Drilled and tapped 3mm the first hole through web, from the top of the web to the crank centreline (photo 1). Set up to drill the second hole through the crankpin (photo 2). Used a wiggler to align the spindle with the hole mark (photo 3) and drilled till it broke into hole 1. Tapped 3mm. Also used a jewel screwdriver in hole one to see when I break into the hole. I got this idea from someone on the forum but can't remember who it was. SORRY. Good thing I had the extra long drill for this operation (photo 4).

 

[vcutajar]

Hole 3 was drilled in the crankpin until it broke into hole 2. Used the same screw driver to know when I reached hole 2. Next time I will do the forth long hole in the crank to meet hole 1.

 

[vcutajar]

Fourth hole finished and tapped 3mm. Used a steady rest to support the crankshaft. Started the hole using a normal size 2.5mm drill then continued with the long drill. I need to get me some 3mm grub screws to plug the holes that were tapped. One more hole needed in the crankshaft. This will be the oil feed hole but will do it at the same time when drilling the crankcase.

 

[metalmad]

Hi Vince
Looks like your getting heaps done Mate
I recon you will get her running before I finish the Wallaby :big:
Pete

 

[vcutajar]

Pete

Methinks you are way ahead. :big:

Vince

 

[vcutajar]

Made the oil inlet hole in the front crankcase casting. Held the casting in a vice and milled flat the boss of the oil inlet. Drilled through a 2.5mm hole and then drilled and tapped 5mm.

Next the oil inlet hole on the crankshaft which should meet the previously drilled hole in the crankcase. With the crankcase still in the vice, inserted the crankshaft and positioned it at TDC. With a transfer punch through the crankcase 2.5mm hole marked the crankshaft. Drilled a 2.5mm hole in the crankshaft and filed it with a small round file as per instructions.

 

[vcutajar]

Started work on the bronze counterweights for the crankshaft. The bronze casting came with the kit. Milled the bottom to give me a flat surface and then milled the top.

 

[vcutajar]

Continued work on the counterweights. Brought down the thickness of the casting to dimension on the lathe. Then mounted the casting on the milling table (photo 2). Used a 12mm endmill and milled the slot to the required depth of 3.175mm.

 

[vcutajar]

Using the DRO (thank God for them) I widened the slot to 12.7mm all the time using a piece of the excess material I had hacksawed off when making the crankshaft as a gauge. I do not want the slot to be a sloppy fit in the crankshaft webs.

Now I need to ask a question on the forum but I am going to post it in the questions and answers section as I think my question will get more visibilty there.

http://www.homemodelenginemachinist.com/index.php?topic=17747.0

 

[vcutajar]

Did some more work on the balance weights. Hacksawed the casting so that I could separate both balance weights. Milled the flat at the top on both weights and then marked them so that next time I will mill the 15 deg. sides.

 

[vcutajar]

Milled the angled sides which I marked yesterday. The rest will be turned in the lathe when the balance weights are fixed to the crankshaft.

Made myself an extension for a 5.5mm slot drill (photo 3). Used a piece of 10mm silver steel, drilled and reamed 6mm (for the slot drill shaft), cleaned the bore and slot drill shaft with surgical spirit and superglued the slot drill in the shaft. I will let it cure till tomorrow and test it out. Still not sure if this will actually work out. We'll find out tomorrow.

 

[vcutajar]

Today I tried using the extended 5.5 slot drill that I made yesterday. Used a piece of scrap mild steel, drilled a 3mm hole, drilled with a 5mm drill to a 2mm depth and then counterbored with the 5.5mm slot drill. I am happy to report that the extension worked and the glue held fast.

I drilled 5mm to a 2mm depth to give the slot drill less work to do.

Now I will make a similar extension for a centredrill.

When I am finished with these extensions I intend to try and remove the 5.5mm slot drill from the extension. If I heat it up do you think I will be able to pull out the slot drill? What do you think?

 

[vcutajar]

Yesterday I made an extension for a centre drill (photo 1).

Today I drilled and counterbored the crank shaft webs. I put a piece of brass between the webs and clamped the crankshaft in the vice using an engineer's square to align it upright (photo 2). Using a wiggler aligned the spindle to the marked hole and then using the extended centre drill started the hole (photo 3). As you can see it was a tight fit. Drilled the hole 3mm with a long series drill. Then using a 5mm drill drilled 1.5mm depth. After that used the extended slot drill and counterbored to a depth of 2mm (photo 4). Another tight fit.

Made the other 3 holes using the same procedure.

 

[vcutajar]

Cleaned up the holes and counterbores and decided to give the balance weights a trial fit.

OMG there is something wrong here. :redface2: No way the connecting rod is going to pass between the balance weights. The balance weights should end up flush with the webs but for some reason they were not. Started checking dimensions of the webs and balance weights. Everything seemed correct (or so I thought). Measured again a couple of times but could not find what was wrong. Lit up a cigar and it was finished in record time. Panic was starting to take over. I was convinced that there was a wrong dimension on the plans. Finally, after 30 minutes, I found MY mistake. I misread the diagram of the slot of the balance weight. :wall:

Thank God it's a fixable mistake. All I need to do is make the slot deeper. So next time, I will have to re-mill the slots and hopefully keep the same width of the slot.

 

[vcutajar]

Well, today I milled the slot in the balance weights deeper. Did a trial fit and now it looks better and there is enough space between the balance weights for the connecting rod to pass through. Sorry, no photos today as I forgot the camera at home. Next operation is to drill and tap the holes in the balance weights.

 

[steamer]

Hey Vcutajar!

Keep at it man, you'll get there!

Nice save!

Dave

 

[vcutajar]

Thanks Dave

Vince

 

[vcutajar]

Now that looks much better (photo 1) and there is enough space for the conrod to pass between the balance weights.

Marked for the holes in the balance weights with a transfer punch. Drilled and tapped the holes 3mm. Setup the crankshaft with the balance weights on the lathe (photo 2) to trim the sides of the balance weights and webs at the same time.