Have ended up with several low-mileage sets of P&L sitting around..
They measure nicely, and that's why I kept them,
And now it's time to use a couple of sets.
While i know that a 'plateau' finish 250/500 grit 3-arm power-stroke Sunnen with torque plate is technically correct,
Many motors are built that don't need the cylinders correctly straightened and made round.
I had good luck using an unknown dingle-ball years ago..
If there is just going to be a quick 'glaze breaking' using a hone for a motor to go back together,
What would be 'best' practices..?
Tons of these 3-arm hand-held 'glaze breakers' in 220 grit on ebay -->
https://www.ebay.com/itm/2-to-7-Glaze-B ... 5062!US!-1
Dingle-balls as well -->
https://www.ebay.com/itm/3-3-4-Engine-C ... Sw6btXRFVg
They all seem to be 120/240/320 grit; With few in finer grits.
Maybe a dingle-ball in 120, and finish with a 3-arm 320?
What would be 'best' for your typical Cima/KS/Cofap/Metal Leve/AA ACVW application?
Glaze Breaker?
-
Clatter
- Posts: 2046
- Joined: Sun Apr 28, 2002 1:01 am
Glaze Breaker?
Speedier than a Fasting Bullet!
Beginners' how-to Type 4 build thread ---> http://shoptalkforums.com/viewtopic.php?f=1&t=145853
Beginners' how-to Type 4 build thread ---> http://shoptalkforums.com/viewtopic.php?f=1&t=145853
-
raygreenwood
- Posts: 11907
- Joined: Wed Jan 22, 2003 12:01 am
Re: Glaze Breaker?
If the cylinders are indeed "straight"....you can do an excellent job with a 240 grit Flex-hone followed up by a 600 grit flex-hone in reverse to put the plateau on it.
Ideally you really should have a torque plate as well...but if its just a resurface...."new tooth" on teh cylinder wall...it should make no difference for the total of about 20-30 seconds you will be working with it. Measure before and after but you should not need to remove more than about .001" to get the surface right with a nice correct cross-hatch and plateau.
I would never even try a Flex-hone for straightening or boring oversize a cylinder set. That is a job for a Sunnen hone system or equivalent. But I have done numerous cylinder re-profiles with flexhone and they come out as good as even a Sunnen can do ...without going over sized. I know this because I have a surface profiler to to check. Ray
Ideally you really should have a torque plate as well...but if its just a resurface...."new tooth" on teh cylinder wall...it should make no difference for the total of about 20-30 seconds you will be working with it. Measure before and after but you should not need to remove more than about .001" to get the surface right with a nice correct cross-hatch and plateau.
I would never even try a Flex-hone for straightening or boring oversize a cylinder set. That is a job for a Sunnen hone system or equivalent. But I have done numerous cylinder re-profiles with flexhone and they come out as good as even a Sunnen can do ...without going over sized. I know this because I have a surface profiler to to check. Ray
-
Clatter
- Posts: 2046
- Joined: Sun Apr 28, 2002 1:01 am
Re: Glaze Breaker?
Thanks, Ray.
Was hoping you would chime in..
The flex-hones you recommend are of the ‘dingle-ball’ variety?
Was it you that posted something somewhere about using a 3-arm, and then just wrapping/clipping the stones in some finer grit (600) wet/dry for the plateau finish operation?
That final operation is just a few seconds/strokes, correct?
Was hoping you would chime in..
The flex-hones you recommend are of the ‘dingle-ball’ variety?
Was it you that posted something somewhere about using a 3-arm, and then just wrapping/clipping the stones in some finer grit (600) wet/dry for the plateau finish operation?
That final operation is just a few seconds/strokes, correct?
Speedier than a Fasting Bullet!
Beginners' how-to Type 4 build thread ---> http://shoptalkforums.com/viewtopic.php?f=1&t=145853
Beginners' how-to Type 4 build thread ---> http://shoptalkforums.com/viewtopic.php?f=1&t=145853
-
raygreenwood
- Posts: 11907
- Joined: Wed Jan 22, 2003 12:01 am
Re: Glaze Breaker?
Take a look on Flex Hones (BRC) site. They have pretty good directions .I recommend making a mounting plate out of steel or aluminum...and a top flange/torque plate... just with a hole saw and using normal threaded rod to hold these. I "have" bolted them to a case half and honed them and it works fine but gets nasty.
The trick with using a flex hone is keeping constant and not insanely fast speed....and PLUNGE rate. You are technically making three passes.
1. The first pass with 240 grit or whatever the coarse grit you require.....and make sure you order the correct abrasive material for cast iron...which I think IIRC is silicon carbide. This first pass is a slower plunge rate. You are NOT trying to put the correct hatch angle on yet. You are getting the small amount of material removal and stroke overlap uniform.
The hatch marks made from this first pass should look shallow like 25-30*.
2. The second pass....is pretty much as Flex Hone/BRC notes...is pretty much about as fast as you can. This should get you a higher angle hatch mark in the 40-50* range. You only need enough passes to orient the surface and make the hatch marks uniform.
3. The last pass is with the 600 grit. It does not take much. It should run at the same speed as the 2nd pass of the rougher stone to keep the hatch angles the same.
Look on the first page of this current build thread down the page. You can see where I do mine.
https://www.thesamba.com/vw/forum/viewt ... 26&start=0
Also...do not get hung up in exact angles. You can see fro my photographs that the factory didn't get too hung up in it. And...understand the geometry of things
....if a shop using A high end Sunnen hone...sets a plunge rate and spindle speed to get "X" hatch angle.....that hatch angle at that same spindle speed and plunge rate will be different by a few degrees....on a cylinder that is larger or smaller in disameter...for example 90mm to 94mm.
Why?...because at a fixed spindle speed....diameter= perimeter...which = number of actual rotations at any given spindle speed. Perimeter = distance. Distance takes time. And the spindle is not only spinning...its rising and falling. So the angle varies.
On cylinders that have some wear ...diameter wise....but are otherwise EXCELLENT....I do not like to trust them to a shop with a hone system . The expanding or multi-stone hones....even with careful pressure , speed, abrasive and plunge selections....they "cut" a lot more efficiently than a flex hone....which means faster.
Far too many times....I have taken in a set of cylinders...excellent used....that "could" of honed properly give me another 100k miles of perfect running.....but have NO ROOM to lose more than the amount of metal required to put a new tooth/hatch pattern on them....and they come back too far oversized...junk.
For this purpose...a flex hone when carefully used...is excellent.
I also recommend getting an old scrap cylinder and using machinist dye on teh inside to practice your strokes and get into the groove of things before doing the good ones. Ray
The trick with using a flex hone is keeping constant and not insanely fast speed....and PLUNGE rate. You are technically making three passes.
1. The first pass with 240 grit or whatever the coarse grit you require.....and make sure you order the correct abrasive material for cast iron...which I think IIRC is silicon carbide. This first pass is a slower plunge rate. You are NOT trying to put the correct hatch angle on yet. You are getting the small amount of material removal and stroke overlap uniform.
The hatch marks made from this first pass should look shallow like 25-30*.
2. The second pass....is pretty much as Flex Hone/BRC notes...is pretty much about as fast as you can. This should get you a higher angle hatch mark in the 40-50* range. You only need enough passes to orient the surface and make the hatch marks uniform.
3. The last pass is with the 600 grit. It does not take much. It should run at the same speed as the 2nd pass of the rougher stone to keep the hatch angles the same.
Look on the first page of this current build thread down the page. You can see where I do mine.
https://www.thesamba.com/vw/forum/viewt ... 26&start=0
Also...do not get hung up in exact angles. You can see fro my photographs that the factory didn't get too hung up in it. And...understand the geometry of things
....if a shop using A high end Sunnen hone...sets a plunge rate and spindle speed to get "X" hatch angle.....that hatch angle at that same spindle speed and plunge rate will be different by a few degrees....on a cylinder that is larger or smaller in disameter...for example 90mm to 94mm. Why?...because at a fixed spindle speed....diameter= perimeter...which = number of actual rotations at any given spindle speed. Perimeter = distance. Distance takes time. And the spindle is not only spinning...its rising and falling. So the angle varies.
On cylinders that have some wear ...diameter wise....but are otherwise EXCELLENT....I do not like to trust them to a shop with a hone system . The expanding or multi-stone hones....even with careful pressure , speed, abrasive and plunge selections....they "cut" a lot more efficiently than a flex hone....which means faster.
Far too many times....I have taken in a set of cylinders...excellent used....that "could" of honed properly give me another 100k miles of perfect running.....but have NO ROOM to lose more than the amount of metal required to put a new tooth/hatch pattern on them....and they come back too far oversized...junk.
For this purpose...a flex hone when carefully used...is excellent.
I also recommend getting an old scrap cylinder and using machinist dye on teh inside to practice your strokes and get into the groove of things before doing the good ones. Ray