[How-To] How to make a not so straight hole straighter and maybe slightly larger

I’m trying to figure out how the hole is crooked midway . If the drill wandered the reamer will follow but if the reamer is as long as the part wouldn’t it make a straight smooth hole though may not come out in the same location center as the start ?
 
Cadillac said:
Run the reamer through again with a heavier oil. Slitting could also open it up.
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Tried a variation of this. No joy. It's a tiny bit looser, I'd guess, but not enough to help. If I slit it, and it's not enough I'll need to get a spiral oversized reamer, or resort to lapping with valve grinding compound.
 
whitmore said:
@mmcmdl is right, it doesn't have to be extremely accurate; I'd pull out a rattail file and
see if sighting down the bore suggested a region that needs attacking. Alternately, hones can be
made with ease, using a hammer blow on a mild steel rod; chucked in a hand drill.
Abrasive paste doesn't remove much, or fast, but there's not much removal required here..
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I've had to go the abrasive paste route before. It's slow. But I haven't heard about the hammer trick before. Do you smack the diameter to upset it to a slightly wider diameter? How much of a blow is needed? I have some stock that is about 0.373 or so that I could start from. I'll check to see if it will pass all the way through first. Gives me an idea of the nature of the problem.
 
Make a new one by holding the stock in the chuck and compare the two parts.
 
Alcap said:
I’m trying to figure out how the hole is crooked midway . If the drill wandered the reamer will follow but if the reamer is as long as the part wouldn’t it make a straight smooth hole though may not come out in the same location center as the start ?
Click to expand...
Don't really know if the bore is crooked midway. Don't know if this matters, but my reamer flutes are 2" long, but the hole is 3" deep.

The bushing hole diameter is larger than the short dowel diameter, since I can push the dowel through. The short dowel diameter is greater than the boring bar diameter, so the boring bar should just pass though also. That leaves me with a crooked bar or hole, or something in the hole causing a problem. I can put the bar on a surface plate to see if it is straight or not.

Reaming or lapping seems to be the answer, no matter what.
 
You drill until your boring bar fits.

Then bore to size.

Sent from my SM-G781V using Tapatalk
 
tq60 said:
You drill until your boring bar fits.

Then bore to size.

Sent from my SM-G781V using Tapatalk
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Department of circular redundancy! These bushings are for my boring bars. If I don't make the bushings, can't use the boring bars. But yes, that is what should normally happen. Soon I will be able to do what you said.
 
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