PM Research no.5 .......have a Coke (bottle)!

[Jasonb]

You won't be able to thread that.

I might be tempted to come up from below and fill the holes in the bottom flange once you have done the tapping.

[crueby]

Just went and looked at the one I built many moons ago, one of the first I built, and it looks like I drilled a set of larger holes in the base in line with the bearings, so I could get the tap up from the bottom to the crank bearings.

[Sanjay F]

This is clearly an issue with this build and looks like there have been many ways to approach it. Here are 2 photos from 2 videos, the 1st one is Brandon's idea with 2 locking nuts and the second is basically using a pair of needle nose pliers.

As can be seen from the photos there seems to have been several variants of this engine; look at the valve slide mountings, completely different.......

[EricB]

You seem to have missed this in the diagram. You need to mill away the sides to get clearance for your tools.

Eric

[EricB]

When I built mine I made an extended tap handle.

Eric

[Sanjay F]

Hi Eric

You are correct, I know I need to mill away the sides, I just haven't done it yet and am still waiting for a long drill bit to arrive which can reach the bearing surfaces. The tap handle idea is great, but unfortunately, the valve slide guides are different on your casting than on mine (see picture below). Your engine has the circular moutings (like the picture above) whereas mine has one side of the valve slide cast onto the main casting. I'm not sure when or why PMR changed the castings but it has made the tapping of the bearing holes more difficult!

[EricB]

I was thinking that if you mill the clearances then you could probably use a length of rod that fit the slots and add a short coupling (like a socket) to connect the rod to the tap.

I used brass because that's what I had on hand at the time. I found the idea from some clockmaker's tips.

Eric

[Sanjay F]

That's a good idea, similar to what Jason mentioned; first I need to mill the slots and work out the clearances. These things are always interesting challenges in any build and are good learning exercises! 

[Sanjay F]

Drilled holes in the bearing and valve slide caps. The 'long' drill bit arrived and is still not long enough so made an extension piece to hold it........ going to have to approach this with caution!

Still waiting for an appropriately sized ball nosed mill to arrive in order to cut the recesses to enable the drilling

[Sanjay F]

The rear 'easier' bearing has now been drilled, tapped and is in place .....thank goodness! I used the 'Brandon' method of 2 lock nuts on the tap and gently wound it in with a spanner.

Hopefully I can move onto the front bearing cap when the end mill arrives

[EricB]

 

[Krypto]

Very clever! I have one of these kits waiting patiently in my "stash" and I'm great enjoying your build.

[Sanjay F]

I don't know if it was the 'right' way, but I made the v-shaped slot in the valve slides using a 90 degree chamfering tool; it worked out so I guess that's the main thing!

[crueby]

The  right way is any one of the many ways that work!

[Sanjay F]

Made the slots in the valve slides to enabling drilling of the front bearings. Both bearings caps are in position, with the bearings now drilled and reamed to size. It looks off centre but that's shape of the boss as a 5/16" rod spins nicely

I'm slowly getting the feel for Ali instead of the cast iron which is what I'm most used to.....