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Webster IC Engine build log.
NickG:
Chris, nice work on the cutter cutter. Can't remember, have you done gears like this before, or did you use the single point tool for all of them?
Nick
raynerd:
Yes Nick, I attempted to cut the gears for my ongoing clock project but I have never used a button tool like this to cut the gears. I used a similar form tool but out of HSS to profile the cutter, moving it from one side and then the other. Stew and I had a good crack at it and he managed it with me last year but to be honest, I`ve struggled accurately moving the profiling tool to the other side to get the correct measurement and a symetrical shape. I must admit, I like this idea of a button tool as that is all set out for you, the profile will be correct providing it cuts OK. I also made a multitooth cutter with Stew. Again this worked well but the concern is that if just one of the cutters is a little out, it`ll effect your cut. I think with this only cutting ally, I`m going to use a single point cutter.
Here is the session that I had with Stew cutting gears!!: http://www.raynerd.co.uk/?p=607
I`m just about to go and use the furnace up in DT in a few minutes during my lunch hour and harden the cutter tips.
Hopefully I`ll have a go cutting the cutting tool tonight.
Chris
madjackghengis:
--- Quote from: craynerd on February 02, 2011, 06:26:22 PM ---Hi Jack, thanks for your input regarding the piston seals. I`m not happy with the base material and so until I can save up a little cash for an all base (I`ve spent far too much this month to buy ANYTHING), I`ll just keep some bits on hold. Consequently I`ve made a start on the gears. I`ve made the buttons and holder this evening and I`ll take the buttons to work and harden them. Then hopefully in the next few days I`ll cut the cutter and then by weekend should aim at having a start on the first gear. I hope my calculations are correct, I`ve used mainly John Stevensons gear article, I think I`m in control....
--- End quote ---
Hi Chris, I just wanted to remind you, nothing depends on the base, not really, so you can use what you've got at least temporarily, and just leave the base to last, and if what you use in the interim works out, you may find yourself keeping it. These are OUR engines and we can make them look or do what ever we want, no one can tell us what's good or bad, they can go build their own if they don't like it. That's how I tend to look at this, since it is my hobby, and not theirs. Take your time to enjoy the build and take pleasure in finding new ways to do things which people tell you can't be done that way, but spend your time in the shop pleasurably, making the finished product what you want it to be. :beer: cheers :poke: mad jack
raynerd:
Yep, cheers for the encouragement MadJack I need it after the last two days attempts. I`m pulling my hair out here!!
I heat treated the button cutters and all looked well. I hacked off a large piece of silver steel for the cutter itself and mounted on the arbour stew made for me last time I did some gear cutting. Here is the intended blank of silver steel to made into the cutter:
I then parted off the 0.125" wide cutter I needed after centre drilling for fitting onto the arbour. Yes, you hear correctly - I parted!! - look at the new tool! Although delighted with it, more comments will come later in the week, I`m just too stressed with this problem at the moment but cheers AdeV and John, it is through your recommendation :beer: :thumbup:!
Now I often hear people say, "a mill is just a lathe on its side" - obviously in a loose sense. Since I have a DRO on my mill I didn`t and still don`t see why I couldn`t place the cutter form tool in my vice and hold the blank in the er32 collect chuck. That way I can use the DRO on my vice to feed the profiling tool 0.092" into the cutter blank as required. All looked to be going well, the cutter tool the edge of the silver steel blank:
Then it seemed to stop cutting, yet it was still moving into the profiling tool. I had to stop and see what was wrong and then I found that the silver steel cutter blank was cutting the buttons!!
Fine - I made a wrong call and clearly the buttons were not silver steel as I presumed they were (they had gone hard, a file slid off them). So today I managed to get some 0.275" silver steel which is as near to damn it the 0.274" button dia I need. I heated them cherry red and quenched. They were real hard, a file slid right off them. So now I`ve come up stomping from the workshop - the exact same thing has happened again!! :doh: :bang: :doh: :bang: :doh: :bang: :doh: :bang:
What the heck could I be doing wrong. I`m convinced the silver steel is hard, you can`t file it! Yet the cutter blank seems to be cutting/wearing them flat. Exact same problem again. The picture above was my first attempt, but the exact same has happened this evening.
I`ve been sat here thinking and the only thing I could think would be that I was running the blank at too high a speed? I stupidly didn`t consider it but I don`t even know if this was the problem. Does anyone have any further comments or advice before I attempt it for the third time. I didn`t foresee this as a problematic part to the gear making!
....just another headache before bed... :bang:
Chris
marfaguy:
Hello all,
I'll properly introduce my self in the intro section later. I've been watching this thread with great interest and just wanted to throw my .02 cents in.
Feel free to shoot me down if I've really got this wrong.
So just to make sure I understand, the horizontal spinning disc is supposed to
be profiled with what is essentially a double cove cut from both the top and bottom.
The two vertical discs are what is supposed to cut the coves. Hence they should not
have corners cut into them as they are the cutters and not the cuttees, so to speak.
I'm going to assume I've got that right but please let me know if I'm off base.
Looking at the (madjack's reply #57) picture it looks like there's about a 10 degree angle ground into the bar holding the cutter buttons.
Let's call it rake D. So as the horizontal spinning disc is presented and fed into the stationary cutter buttons, the back rake is D degrees
falling away from the front cutting edge. Is it possible that the rake is too much? In other words maybe there isn't enough support behind the cutting edge.
Another possibility is that the cutting buttons need a bit of annealing to toughen them up after hardening. Perhaps the cutting edge is too hard and it's
shattering against the toughness of the spinning disc. Possibly a combination of less rake so there's more support behind the cutting edge and a
bit of annealing after harding the cutters to toughen them up.
What did the swarf look/feel like? If the cutting edge was minutely shattering then rolling into the cut and abrading the cutters then I would
think the the swarf would be very fine.
The last picture in Craynerd's reply# 57, it looks like the bottom button cutter shifted counterclockwise.
Maybe an optical illusion in the picture but maybe not. Did something shift?
-Charles
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