Ideas for sanding (cutting) the base, no lathe.

[beaglebriar]

I cut base and squish for $50.

And you do a very nice job.

Btw are you still working out of town??

 

[ANewSawyer]

Stupid question, does the squish have to be cut if the base is cut? I would think if you could cut the base, and it not to be too thin when you achieve your squish, that it would be good enough.

 

[A.E.E.llc]

I'd like to see the manufacturers blueprints and geometrical tolerances for cylinders. I bet the bore diameter, concentricity, and base perpendicularity is extremely precise.

Sanding a little off a base for yourself may and could work just fine. Doing it for others is asking for trouble, especially if a lot is removed. Once you lead off a little it would be like a rumor, gets worse.

 

[A.E.E.llc]

Stupid question, does the squish have to be cut if the base is cut? I would think if you could cut the base, and it not to be too thin when you achieve your squish, that it would be good enough.

Its not a stupid question. My preference is not to have a squish tighter than .020

Let's say your saw has a squish of .040 with gasket. You can remove .020 off the base retaining .020 squish and using the gasket.

 

[ANewSawyer]

So, no, you don't have to cut the squish. I am trying to understand why you would cut squish. Maybe squish is to tight with out gasket so cut squish to get 0.020?

I would like to see spec like that too. It would help to answer my questions. The only place I have learned is on the web here and at AS.

 

[mdavlee]

And you do a very nice job.

Btw are you still working out of town??

It's not too hard to do. I cut squish by hand still.

Yep

 

[A.E.E.llc]

So, no, you don't have to cut the squish. I am trying to understand why you would cut squish. Maybe squish is to tight with out gasket so cut squish to get 0.020?

I would like to see spec like that too. It would help to answer my questions. The only place I have learned is on the web here and at AS.

Some may desire to cut more off the base to get the exhaust port timing to there preference or increase compression.

 

[czar800]

Sanding a little off a base for yourself may and could work just fine. Doing it for others is asking for trouble, especially if a lot is removed. Once you lead off a little it would be like a rumor, gets worse.

Well said, I sand only my own stuff!! So if one ever comes unglued it's mine!

I will say I've put some real hrs on a few saws that I sanded.... maybe someday I'll pull one a part and take a look..

 

[dbittle]

Same here, I hack up my own equipment only. I was really pleased with how it turned out though. For me, it was the fun and challenge of thinking through the process and doing it myself that was enjoyable. So I would encourage the OP to prepare a plan, gather some supplies, and go for it. Measure the thickness of the cylinder ears before he starts, measure them periodically during the sanding process, record and post the measurements and see how close he can keep it.

 

[t4driller]

I sanded almost .050 off the base of my 066. I wouldn't recommend going that far but it worked out good for me. I took alot if measurements of the base and squish as I was going. You need a very flat surface and keep the sand paper very tight on surface so it doesn't bunch up on you. I also went over the inside and outside edges of the base with my burr to put a small bevel on so it wouldn't cut into the sand paper. Once you get down to the plating you will have to keep putting a bevel on it. I went in very small increments trying to keep everything true. I had more time in measuring and taking cylinder on and off then I did in sanding. Also sanded the squish band with a old piston with sandpaper glued to it.. next time if I need to go this far it will get sent out to a machinist. It was for my personal saw.

 

[jmssaws]

I've cut some bases that certainly wasn't flat from the factory.
If 003 or so is a problem then how you tourqe the cylinder would affect it.

No possible way that every case half and bearing pocket or cylinder could all be identical.

 

[huskihl]

I cut a 40 or 50 grit sanding belt to make it one long piece. Never gave the plating any thought. Afterwards, once I got a lathe, I pulled the jug and turned it on a mandrel to see how close it was. I was within a couple thousandths.

One thing about sanding them down by hand; there's plenty of time to check base thickness on 4 corners with a caliper

 

[huskihl]

I didn't spin the jug like t4 did though. I slid it the length of the belt, turned 90°, repeat.....for over an hour

 

[t4driller]

I didn't spin the jug like t4 did though. I slid it the length of the belt, turned 90°, repeat.....for over an hour

I tried sliding it , but didn't work so well for me. I just rocked it back in forth 10 times then turned it 90. Kept doing it til I got all the way around. Then checked my measurements . Repeat...

 

[huskihl]

I tried sliding it , but didn't work so well for me. I just rocked it back in forth 10 times then turned it 90. Kept doing it til I got all the way around. Then checked my measurements . Repeat...

You forgot about the other 2500 repeats....

 

[t4driller]

You forgot about the other 2500 repeats....

Truth

 

[Al Smith]

One problem checking all four corners is they aren't indentical even from the factory because it's a casting .

 

[dbittle]

Now we need a thread on how to hack out raising the transfers!

 

[A.E.E.llc]

I've cut some bases that certainly wasn't flat from the factory.
If 003 or so is a problem then how you tourqe the cylinder would affect it.

No possible way that every case half and bearing pocket or cylinder could all be identical.

They have geometrical tolerances to follow set by the engineers.

.003 can be huge in my world. Flat and perpendicular are two totally different things.

 

[jmssaws]

They have geometrical tolerances to follow set by the engineers.

.003 can be huge in my world. Flat and perpendicular are two totally different things.

That's what I mean by bearing bores,I've just changed one case and sometimes it's not even close to the other one.
The crank not sitting square with the bore is the problem I see. If the cylinder is leaning forward or back a few thousandths I can't see what that would hurt, side pressure would be the killer.