Thank you Tree Monkey

[LegDeLimber]

How many of you guys have seen a Neway brand, valve seat cutter?
(S.O.B. on the tool truck [mac] never did bring me that 15/60 deg head, he promised.)

So how soon do we see someone putting a ball bearing in the combustion chamber to
spin the boring tool against?
You'll want to move the cutter slot off to a more tangential(?terminology) position, so as to have the center
area of the shank/arbor for a solid surface
the flatter you can get the initial cut, then the less you'll have to leave for the sanding operation
to flatten out.
Or how about a center bolt and jam nut to set the depth?
But watch out and don't gouge out the chamber with that idea.
still would want a bearing or something similar in there to spin against
Not twist the bolt head directly in the chamber.
or uhm maybe a stud and jam nut with an acorn nut and some lube?
Of course an offset combustion chamber will be a problem with this idea.

Now the real internet points go to the first sharpster who successfully clamps
the cutter onto the side of the arbor, with a clearance, be it a step ground into the cutter
or a spacer block or...?...and cuts the base of a cylinder with spigot.
Sorta hard to sand/lap one of those down.
Hmm, guess we'd be stacking a bit of shim/paper in the head to bottom the arbor against to set the cutter position.

I once vice-gripped a cutter onto about 8 ft long shaft and ran it through the entire length
of a door, in order to cut a spot face for some bushings.
and yes I had to make the bushings too.
The door was going to have locking rods and a hand wheel(bank vault style) installed in it.
Was pretty cool looking when we finished that job.
Motor Yacht work, those people have genuine F-you money and they DO like expensive
Mods on those yachts

 

[David Young]

Nice ingenuity guys.

David, love the idea of using an old piston. What could possibly fit better?

I'll be doing this for sure on my next build. Weld a handle to the piston bottom as well.

Do you guys keep the cutter stationary and rotate the jug on it or vica versa?

Yes I move the jug

The center bolt I tapped some threads in the piston. Used a nut on the bottom to lock it in. Then I put a socket on the nut. To hold in the vice.

Not bag lapping here but I wouldn't have figured this all out with out Scott's pictures.

Part I love is the $0 part. Junk yard dog style. I'm sure what I did will kick start someone else's imagination. Post up the pics with you improvements/ ideas

 

[David Young]

Today i cut the squis band on a Husqvarna 55 jug using a hand tool like Tree Monkey .A 45 mm bolt , a slot cut with a angle grinder and the cutting part made of a Stihl plate file. I made the cutting part, jammed in the slot with a hammer and made that sharp with the angle grinder. It works very well, so Thank you Tree Monkey!.

Thanks for starting this

 

[big t double]

Yes I move the jug

The center bolt I tapped some threads in the piston. Used a nut on the bottom to lock it in. Then I put a socket on the nut. To hold in the vice.

Not bag lapping here but I wouldn't have figured this all out with out Scott's pictures.

Part I love is the $0 part. Junk yard dog style. I'm sure what I did will kick start someone else's imagination. Post up the pics with you improvements/ ideas

that's very cool, thanks for posting the pics. what is your cutter made out of if you don't mind me asking?

 

[David Young]

that's very cool, thanks for posting the pics. what is your cutter made out of if you don't mind me asking?

A piece of a file shaped an sharpened with a dremel

 

[big t double]

Poor folks have poor ways. View attachment 401558

I gave your method a try last night. I'm still not getting all the way over to the edge but I still need to tweak it anyways...thanks @David Young and tree monkey

 

[Tor R]

I gave your method a try last night. I'm still not getting all the over to the edge but I still need to tweak it anyways...thanks @David Young and tree monkey
View attachment 476650
View attachment 476651

thanks for bumping up this thread.
I love your way to think David! Seems I can use my scored 254/262 pistons to something after all

 

[drf255]

Use a wood chisel to scrape that edge band. Actually the perfect shape and does a great job.

 

[nenicu]

Here is my tool.

 

[nenicu]

More

 

[drf255]

Mine's bigger

 

[Tor R]

I have a few piston and jugs to practise on this weekend

 

[David Young]

I also will put a screw behind the cutter to hold it in place. I also recommend using sandpaper to smooth everything out like scott does.

 

[LegDeLimber]

I gave your method a try last night. I'm still not getting all the way over to the edge but I still need to tweak it anyways...thanks @David Young and tree monkey
View attachment 476650

you may already have the file piece moved outward enough.
but if not, Do you have some straight, durable surface to press the piston against
while tightening the clamping screw?
You might find that moving the cutting point over the full extended section of the skirt makes it easier to do.

IF you have a nice surface with a square 90 deg sidewall to set the piston on and push it against the sidewall/corner, it will be easier to hold everything
while tightening the clamp screw.

Now then, has anyone got a poor mans mandrel for reaching out over the spigot wall to face the flange, to drop the cylinder??
Getting the face cut DEAD FLAT is the catch there.

 

[big t double]

you may already have the file piece moved outward enough.
but if not, Do you have some straight, durable surface to press the piston against
while tightening the clamping screw?
You might find that moving the cutting point over the full extended section of the skirt makes it easier to do.

IF you have a nice surface with a square 90 deg sidewall to set the piston on and push it against the sidewall/corner, it will be easier to hold everything
while tightening the clamp screw.

Now then, has anyone got a poor mans mandrel for reaching out over the spigot wall to face the flange, to drop the cylinder??
Getting the face cut DEAD FLAT is the catch there.

I'll be 100% honest, I don't quite know what you mean. Full disclosure I'm a complete hack and have never ported a cylinder in my life. But I figure if I'm going to try I may as well figure out how to cut a squish band manually. If it's good enough for tree monkey it can't be all that bad, right? I did play around with the "cutter" today after work...I put the piston in the cylinder upside down and moved the cutter over so it barely touched the cylinder wall then snugged it down. Rigged it up in the vise using a nut and a socket and here's what I got...


Seems to have taken the ridge off. Next up...accurately trying to lower the base with no lathe and figuring out a good place to start with timing numbers...

Is @wcorey selling his adjustable mandrels yet

 

[LegDeLimber]

big t double: I got a few questions.
Do you have a nut under the piston crown/dome, that's on the end of the torx screw?
And is this is you turn/hold the piston?
are you turning the cylinder so that the piston is like it spins in the direction of the red arrow?

IF so, then that's why the file chip wants to loosen and slip.
I see the slip lines (lt blue arrows)
I see that file teeth are oriented in the direction/hook like the black line (over the file)
So I understnd why you would want to turn in that direction, so as to cut with the file teeth.

IF and a big IF, You could find a file with the teeth cut on the opposite bias-angle
then it would allow for putting the file chip on the opposite side of the screw.

This would have you turning in the other direction, so that the nut is trying to tighten on the screw vs loosening.

The other thought is to grind off the file teeth and then use the file chip as a strait edged cutter, like a lathe tool would look.

Edit: I just looked at my Valorbe ,square cutting file here and the one with teeth that are strait across, should let you use it on the other side/direction!

 

[big t double]

big t double: I got a few questions.
Do you have a nut under the piston crown/dome, that's on the end of the torx screw?
And is this is you turn/hold the piston?
are you turning the cylinder so that the piston is like it spins in the direction of the red arrow?

IF so, then that's why the file chip wants to loosen and slip.
I see the slip lines (lt blue arrows)
I see that file teeth are oriented in the direction/hook like the black line (over the file)
So I understnd why you would want to turn in that direction, so as to cut with the file teeth.

IF and a big IF, You could find a file with the teeth cut on the opposite bias-angle
then it would allow for putting the file chip on the opposite side of the screw.

This would have you turning in the other direction, so that the nut is trying to tighten on the screw vs loosening.

The other thought is to grind off the file teeth and then use the file chip as a strait edged cutter, like a lathe tool would look.

Edit: I just looked at my Valorbe ,square cutting file here and the one with teeth that are strait across, should let you use it on the other side/direction!

K...here goes
Yes there is a nut on the screw under the piston. This, however, was an afterthought that I didn't put on until today at work...I didn't fully read David youngs post last night when I made this thing, about how he secured it to the vise. I drilled and tapped the piston for this torx bolt last night. So then yes...this is how I held/turned the piston today. Last night I just used a pair of pliers on the wrist pin to turn it to see if it would even work. Yes I turn the piston in the direction of the red arrow.
The slip occurred last night...but when I first tried it I didn't have a washer under the torx bolt...after I added the washer and tightened it down the slip was reduced greatly. I think I'd like to add a notch to the file piece to fit around the bolt to hold better yet.
That piece of file has been sharpened so the file teeth aren't playing any roll...so yes...I can sharpen the other side as you suggested so it turns properly with the nut...this was a seat of the pants project last night...I had no real clue what I was doing. I hope that answered your questions in a somewhat clear and concise fashion. I'm a general idiot though so...

 

[LegDeLimber]

I flipped your image so that the view looks like what I'm babbling about.

I Like the idea of a notch to accommodate the central (in the piston) screw.
Once you've got it dialed in, You might put a -low- head screw
behind the file (the yellow circle).
The screw head would need to be a little below the top of the file surface.
You just want a screw with a strait sided head, like the center screw has.
then do a little grind to get the head below the file height.

 

[big t double]

I completely understood your babble, it made perfect sense yes I need to sharpen the other side of the file to spin it the way you suggested. And I like your idea of the backup screw. I'm not sure how flat it's cutting though and my sharpening skills definitely leave something to be desired.
To be perfectly honest...I'd like to find a local machinist to make me a proper mandrel though. Need to find some metal round stock.

 

[czar800]

Very good thread! I plan on doing something similar myself after reading this. Could you not grind the screw/bolt head (yellow) so it will cam the file in and out as needed also?