The valve base thread that Darren had started involved putting a large hole in a piece of steel. I had suggested using a "tree panning" tool. I knew I had pictures of one I made. I'd say designed, but the tool has already been designed it just needs a mod to make it work for your application. So with that in mind I've started this thread of a tree panning tool I made for a specific project.
The project involves making solid mount motor plates for a guy that builds drag cars. The plate goes between the engine and transmission and is bolted to the frame. The reason for this is so that the engine doesn't twist itself out of the car on take off from the drag line. The holes are for the bolts that hold the engine and transmission together, a hole for the starter, and a hole to be able to secure the bolts of on the converter and starter ring. Very simple.
Now a small short story. The guy that was supposed to originally do them keep coming and asking me how to go about it. I knew what was up. He wanted me to design the fixture to locate the holes and then he would reap the profit. So I sat back and waited. Knowing full well he'd never be able to figure it out. My name got mentioned by another guy that I did some work for and the person that wanted the plates made came to me. When the guy that was going to make them found out he said I couldn't do it because you'd need "modern technology" to do them. Last I looked metal removal hadn't changed much. He was thinking laser or water jet to cut the shapes out. I did it with a drill press and some drills, plus a home engineered tree pan tool.
So, end of short story. Here are the pics as I made improvements to the tool. I'm not going to spend much time explaining every picture since a picture is worth 1000 words. If you have any question feel free to ask and I will try to answer them
First picture is of the Buffalo Forge Drill press I do the work on. It's been modified for a tread mill motor. I have nice variable speed.

Next two pics are of the plates I do. Two different sizes. This one has an 8" dia. hole.

Next is the larger one. It has an 14.25" hole in the center. Both this one and the one above were cut out using a tree panning tool.

Another one I made same as above.

My first attempt to make the bigger hole. I used the headstock from the Sherline lathe. I thought I could mill it out. After the first broken end mill it was back to the drawing board.

I decided to use the tooling I made and use a 1/8" HSS lathe tool. The tool is in the slot with the bigger hole. It work but I broke quite a number to tools because the tool grabbed the aluminum.

Just another pic of the above from different angle. I added the 1-2-3 block in hopes of stopping chatter. Didn't work.

A better view of the cutter and it's shape.

The newer tree panning tool I made. This is version I. Front side.

Another pic of version I.

Back side showing adjustment.

Checking things out to make sure it works.

Closer look at the tool. It's not ground for clearance angles yet.

Made a nice wooden base so I wouldn't damage the table with the tool and also not scratch the aluminum.

More checking for clearances and setting tool to the dia. I need.

My new method of rough cutting the opening. Boy was this tough to do, even with a course blade.

Here are the results. Numerous broken blades and sore hands from hanging on to the saw. But I 'gotter 'er done.

It worked to some extend but would get hung up easily.

Here is the final version. It uses an 1/8" HSS lathe tool and is straight up and down. Works pretty good, but occasionally still jambs up once in a while. What helps is the hand wheel feed the drill press has. They sure made them nice back then.

I hope somebody can get some ideas from this and put it to good practice. I'm not an expert on this method of cutting, but I did learn a lot making the tooling.
Got questions? Ask away.
Regards,
Bernd