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All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Topic started by: JMJ in NC on March 12, 2011, 08:49:37 PM
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I'm going to do some work on my Walther Force 1000. What grit sandpaper is recommended for cross-hatching the cylinder?
Thanks,
JMJ
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Never done it, but I hear from a guy who has done 100's that 320 grit is the one to use....
Bob
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A 140 grit brake hone will do the trick. There are other tools out now that even do a better job. You just have to look. I wore out lots of brake hones when I was tuning...:)
Just be aware of the different hardnesses in tubes. Euro and US are generally harder than Chinese. Go easy at first.
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Thanks for the replies. I have cheap a Harbor Freight brake hone (grit # ?????) as well as the dowel-type sandpaper hone. I've got 400 grit paper, but from what I'm reading 140 - 320 is the way to go.
Thanks - JMJ
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the brake hone is what you want to use.....
I do not recommend using sandpaper to hone the compression chamber of the gun it will not leave as uniform of a finish and you do NOT want a "wavy" finish on your compression chamber walls....and worse then a wavy finish is your more then likely going to end up "coning" the compression chamber making it tighter at the front then the rear instead of parallel and uniform.... and since your seal lives 99% of its life at the front of the chamber it will size itself to the smaller diameter and not seal up well at the rear of its travel...... (yes I know plenty of people have done it but if you have the RIGHT tools then use them in the right spots.....) the sandpaper hone is perfectly good for touching up the rest of the inside of the action though!! just make sure you clean up all your grit when done...... dont want any of that in there to wear and scratch up the works.....
also make sure your stones reach to the end of the chamber..... I usualy have to modify the stone holders a tad to make sure the stones reach to the end and dont leave a bit of a ridge at the front of the chamber..... its a pretty easy job as the stone holders are usualy made out of ALU and are pretty soft so its a simple thing to undercut them a bit with a file to make sure nothing is sticking past the end of the stones......
and remember your really just dressing the surface more then you are anything else so dont go to crazy with it :)
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Great advice - thanks MichaelM & Gene.
JMJ
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I have cheap a Harbor Freight brake hone (grit # ?????)
Drum brake wheel cylinder hones like yours are 220 grit I believe. Hones for disc brake calipers are 400.
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This is the one I have:
1-1/8" Brake Cylinder Hone
http://www.harborfreight.com/1-1-8-eighth-inch-brake-cylinder-hone-97163.html (http://www.harborfreight.com/1-1-8-eighth-inch-brake-cylinder-hone-97163.html)
I bought it after someone posted about it on the Bargain forum.
JMJ
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thats more or less what I use...
getting it extended to reach the end of the chamber is your biggest problem you really have..... I used an old shotgun c;eaning rod and retapped it and threaded the end of the hone so they would screw together and made a nice long extension......
IRL you could prolly use a section of stiff hose or whatever else you can think of to extennd its reach......
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getting it extended to reach the end of the chamber is your biggest problem you really have...
I used a drill bit extension like this one from Sears and it worked great!
http://www.sears.com/shc/s/p_10153_12605_00920920000P (http://www.sears.com/shc/s/p_10153_12605_00920920000P)
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this is a napa flex hone they come in three different grits i work in auto repair they are about $40 it does a good job like some one posted go slow cuts fast.
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Those are good but just to harsh for many of the air guns. Remember metal is not hardened but soft in most cases.
this is a napa flex hone they come in three different grits i work in auto repair they are about $40 it does a good job like some one posted go slow cuts fast.
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I agree with Gene. The Flex Hones must be used very carefully and have ruined many guns. You will usually find after using them that you will have excessive desieling and even detonation. I don't recommend them at all, especially for the compression chamber.
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Not saying it cant be used but I agree with both Bob and Gene..... the flex hones cut VERY fast and since most our tubes are very soft it just makes the problem that much worse... and you end up with not very uniform chambers/oversized chambers or even gouged walls from the wall being so soft....
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Just picked up a 12" drill bit extension from Ace, so I think I'm all set for lightly honing using my HF hone.
Thanks again, all.
JMJ
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Not saying it cant be used but I agree with both Bob and Gene..... the flex hones cut VERY fast and since most our tubes are very soft it just makes the problem that much worse... and you end up with not very uniform chambers/oversized chambers or even gouged walls from the wall being so soft....
One other problem with using flex hones,....
The flex hones have ball-shaped abrasives that can't reach all the way up into very front of the compression chamber bore as well as the 90 degree corners of the "stone" type hones....but the piston seal lip will reach all the way into that forward-most area that the flex hones can't.
Use the right tool = get the right results !!!!
Paul
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Rather than starting a new thread, I'm hoping someone will chime in here...now that I found out i was looking for the wrong type of hone(i was looking for the flex type)..when you start to hone assuming you do use a drill...is it a fast spin, or just a slow turn? when do you know enough is enough?
I'm going to try all of this, so im sure i might be picking some brains a few more times.
Thanks,Jason