We are currently running a honing job (final step before hard chrome plating) on 4pcs thin wall .06w sleeves that we are removing .020-.025 total of material on a 2.5" bore x 14" lg. Parts cant be bored first as wall is too thin and it distorts our of round to far for hone to clean (tried it multiple ways). We are using a MBB machine with a 3GP28 mandrel and A45 stone for roughing and a A55 for finish to RA32 finish. Its taking about 3hrs/pc (which is actually probably pretty decent for the amount of material), but any tips on speeding up removal or at a min increasing stone life? each pc is using 1 set of 3 stones (which again probably isnt that bad) BUT still hoping we can improve time.
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Honing 304ss
- Thread starter Micmac1
- Start date
- Replies 8
- Views 1,630
ballen
Diamond
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
Make a box to hold the tube, then cast plaster of paris around the tube to support the outside. Bore out the tube close to final dimension. Break off the plaster and hone away.
Conrad Hoffman
Diamond
- Joined
- May 10, 2009
- Location
- Canandaigua, NY, USA
That's just nuts. I like the box solution. It's so much material I wonder if you could EDM it to near final size?
Dan from Oakland
Titanium
- Joined
- Sep 15, 2005
- Location
- Oakland, CA
How the heck are you holding onto the tube with out distorting it? An MBB is probably not the best machine to use for that but...….. Ya might fork out for some borazon stones rather than the AL you are using now- buying 3 of them is going to sting your wallet but they cut so much faster than standard abrasives.
I finished one of them, took about 3 hours total. Ended up using a couple rubber strap oil filter wrenchs to hold od, worked well. Was not able to put alot of pressure on it obviously, which is why it took so long. Concentricty to the OD actually isnt important and the tol is +/-.002 on the ID, which i am well within. Good idea on the borazon stones i think there like $130 each from sunnen if i remember correctly. Plaster idea is actually pretty good, may try this one. The EDM idea is interesting, tying to find a edm shop with a reasonable cycle time right now may be difficult tho.
ballen
Diamond
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
(Dry) Plaster of Paris is calcium sulphate. When you add water, it transforms to hydrous calcium sulphate in the form of crystals. When this happens, it expands slightly. That will help to lock your tube in place, but might also distort it, so keep that in mind when you are boring it out. Some more info is here: The Plaster FAQ—Working With Plaster >> Juxtamorph >> United Artworks
gappmast
Cast Iron
- Joined
- May 13, 2007
- Location
- California
Remove the back stone and shoe so you are using two stones and you might get better cutting action. I would try A43 or A53 stones. Everyone want's longer stone life but you have to sacrifice stone for stock removal, as the grit dulls it has to break away so new sharp grit can cut. If softer stones save you a hour per part the extra cost will look cheap.
I don't think Borazon is a good choice on a thin wall part like this.
Order a HF300 strap wrench from Sunnen it will work better and not distort the part like the oil filter wrench
I don't think Borazon is a good choice on a thin wall part like this.
Order a HF300 strap wrench from Sunnen it will work better and not distort the part like the oil filter wrench
Took off the back stone and shoe, running just 2 stones and shoes. Much better cutting action and madrel is no longer binding up in the pc when i try putting a little extra presser on there. I have the HF300 handle, but i did not have strap for it, just used a worn out norton belt from our 4x36 bench grinder, wroked out well. Good tip. Thanks
gappmast
Cast Iron
- Joined
- May 13, 2007
- Location
- California
That Norton belt is the same thing you would get from Sunnen.
