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Post by jspearm1983 on Feb 16, 2019 17:55:08 GMT -5
Micro, I've seen you do some alignment tests after drilling. How close is close enough when you're doing an alignment test on a drilled body? When I squeeze the left side's drill blank between the 123 blocks, my right side drill blank always has about 0.010 space between it and the block sliding on the right side? Is this close enough, or do most people keep trying until they find a perfect drill?
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Post by micro on Feb 16, 2019 19:31:55 GMT -5
I am not sure what most people do. I would think that most pro racers will try and get it as close to perfect as possible. .010 seems like to much to me.
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Post by jspearm1983 on Feb 16, 2019 19:42:09 GMT -5
Yeah, I would think pro racers will drill 20 bodies and pick the best two or three. For my kids Awana race, I think it's good enough to take 1,2, and 3 on the podium.
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Post by jspearm1983 on Feb 16, 2019 19:58:17 GMT -5
The car that had 0.010 was drilled with a 2.3mm bit. Afterwards, I put that bit on the granite surface plate to see if it was true. It definitely had run out, I changed to another 2.3mm bit and am now getting less than .004 gaps in my alignment test. I think ill toss the 0.010 body and redo it with the new bit.
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Post by micro on Feb 16, 2019 20:22:03 GMT -5
That seems more reasonable. Good luck in your race!
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Post by Ember on Feb 16, 2019 22:45:07 GMT -5
If it were the drill bit, wouldn't both sides be effected?
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Post by Professor Moriarty on Feb 16, 2019 22:59:36 GMT -5
I betcha fella more likely buy 10 drill bits that are #43....and pick the tightest fit.
As long as you have a .0895” pin gage in the other side and the car is clamped tight... and you pull out to clear the shavings on both holes... it should be tough to screw up...
Of course... it is only moderately difficult to screw up one of those steps.
And then there is always the chance that the test is slightly flawed...
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Post by Ember on Feb 17, 2019 13:51:16 GMT -5
I don't think it's too difficult to get the drill close, but it's pretty hard to get it "perfect". There are many many ways to get it wrong, but only one way to get it right.
Just the fact that there is a clearance tolerance between the bit and the bushing pretty much assures the drill will not be "perfect". When building the jig there is the initial drill for the bushing that has to be perfect, there is the tolerance in the bushing itself, the run-out in the drill bit, the run-out in the drill or pin vise, the grain in the wood, etc... all adding up to a drill that will rarely be "perfect". If you luck into a perfect drill on one side, what are the odds that you will get another perfect drill on the other side ?....not good IMO. With a little practice with your jig you can get them pretty darn close, but I'm convinced the top guys won't continue a build unless the initial drill is as close to perfect as possible. The slightest amount of toe in/out can dramatically slow a car, why would anyone want to continue a build with a car that is already handicapped?
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Post by jspearm1983 on Feb 17, 2019 23:05:21 GMT -5
I don't think it's too difficult to get the drill close, but it's pretty hard to get it "perfect". There are many many ways to get it wrong, but only one way to get it right. Just the fact that there is a clearance tolerance between the bit and the bushing pretty much assures the drill will not be "perfect". When building the jig there is the initial drill for the bushing that has to be perfect, there is the tolerance in the bushing itself, the run-out in the drill bit, the run-out in the drill or pin vise, the grain in the wood, etc... all adding up to a drill that will rarely be "perfect". If you luck into a perfect drill on one side, what are the odds that you will get another perfect drill on the other side ?....not good IMO. With a little practice with your jig you can get them pretty darn close, but I'm convinced the top guys won't continue a build unless the initial drill is as close to perfect as possible. The slightest amount of toe in/out can dramatically slow a car, why would anyone want to continue a build with a car that is already handicapped? I agree it's hard to screw up while using a jig, because you're basically guaranteed alignment within 0.004. If we assume the fastest pros are perfectly aligned, Are the fastest pros getting drills with less than 0.001 tolerance with some different technique? Or, do you think they luck into it by drilling hundreds of bodies? |
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Eagle
Goodfella
Posts: 2,228
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Post by Eagle on Feb 17, 2019 23:21:54 GMT -5
Or, do they have a more accurate way /technique of checking alignments? Knowing what and how to get the best results goes a long way in creating them. And, most importantly, it allows duplication. |
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Post by Ember on Feb 18, 2019 0:10:50 GMT -5
jspearm1983...I think it's a combo of both. I think they learn their jig, as you did, learning one side seems to be off more than the other. My GB jig is the same way, I have to ever so slightly bias the left side drill for a toe in, or I will usually end up with a ever so slight toe out hole. I also think they go through a handful of blanks before getting a drill job they like. IMO no jig is drilled perfect, no bushing is perfect, no drill bit is perfect, no drill or pin vice is perfect, and we as humans sure aren't perfect. The fact that you were getting drills that were .010 off shows a .004 is by no means guaranteed. I have been guilty of thinking "it's close" and going forward with it, but that's not going to cut it at the league level, I will no longer start a serious build with a drill job that is less than a practical "perfect". How are you testing alignment?
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Post by jspearm1983 on Feb 18, 2019 0:53:42 GMT -5
I test alignment how Micro tested it in one of his videos. Granite plate, strait edge, and 123 blocks. It's been a couple years since I've watched the video. I test for toe alignment, but I don't test to see if the cant is symmetrical to both rear axles. I'm not sure how I would test for symmetrical cant anyway. I think just as there will be small variance in any drill job, there is also slight variance in any alignment test.
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Post by Cherokee Chuck on Feb 18, 2019 2:13:39 GMT -5
When checking for even cant I place my FLAT body on my ground flat piece of granite. Using my go no go cut pin that has a centered point one one end. I insert it to the 3/4" stop with tip out. Using my stainless steel mm rule sitting square on the stone I measure both sides. Compare measurements to each other. Matching measures equal matching cant.
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