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Oblong holes

galt1074

Member
I need a little perspective on drilled holes and maybe some tips if you have them.
I am working on an RV-7 fuselage and the holes below are from F705A
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OIz7G8maZ0zSqXd5IB8MC7OIYhwFWoi82yJTqhpd7reijGDs0Yx9OdXSaZyPaxdAxMmHykd3mAYM4EfIadyyM7rUDWhtuFkiSI-_wC9bOpiPvAA1NfjtlPVPHqI2vfJ2OPWHtBqEXfubfaOGpZvFadv8wRQfnijSW3kSXxBlBCrO2HHWZuvVVPrskotVXOVtB-jDdOjXC5HYn8RD6pcZU4pBzb9PRVDGC5MJ84rkcXsd9yHhXIKLlKnOFU3VsFiMbbKg-QbkLVSYvZ1gmC9qPNPVRezz5_wO9wEkuzxQkVJMwRaCD1K8ho9GOVWTwwJ9PU919DP4vYkSjf_s_ixMmywh_yo4FDcbCMP0g4cvjtT-SS87to7y3U4SMNt5CKi7TlK4Fu929zXeJGmxwGJOuatp74JOvN8rXuA6_EoCPH3Y_gOOqz3W3O92SrbsCX4IeHW8b8aX5E1gpotngQ-huZWd1zCOb7DJf2R_mCxDntoA-EpL4Fe35wwRSXYm5HN8MfJBiqB9OLqBraqaqhJMpSZJV_c4rbfzlZfO68ffV8XzdxQm73pYyKDhQXPQNk0yNlXjzc31FARPr4nJBecrkh83YrlVlP3MkcAbogKSbVvJPxWRUooYwumr0uNod7SEwURH9jnJFM2phlnNRACCVnbONbi4eQs=w800-h600-no

YbkpIW7MrJbrRoArMgfPIxjDfgAyLF0w2jl8YVEi5vVSk457mc48djybprWagTNSqKNtwTqPlqoN8S7R0X7NAv9SJLuZZFH9psuAc5qemTz0hKXTaw3BX02JM-O3rr-hlijH_dGNt7MQahaqGHC1EEtkyq8dWBSwWJ3_1Ux1qfs6ecfgJne2Da31LCa9gty0WUJ8fuI52ReYvHrsZYRS92HFlGPUWmmqs8vrd9QGBoOfZSp1OnvI3ZEfdmXbN7JtVmUw73sCPoDjdXiq6V2hZhHrnnevmdOvAzXxDT80NBVJE8_JMss38XNiUxAbyNKV9wWCU2WyEHa-fV1lWMgGgexdLDGGA19YMcQywmFK5BWV28LXktZw4ldwzxPD3URGFBC9RoIsRBOXEQFSsKGU8X4oCPAp9oj78SZOCoKNzlu-cw-HNUzCOq0fpfKiGUqFsPxypKZ37WEdRFzDFVHwMWDJmnX91JRlikhQgLJT6x5c1uB7xtwSiLu4qpRgKLyqXchq7DRRQ8jYbJtYQQDU11Eir95feHsKyr2WoKKuWyszmLuuVkqAVeA6POA-TGlQXaTTIeDhdkGI6wpzsGjY5efSR9r0OfhSXQDWHNSPTn_EyKyGR1u1pKerF16keNUa-pLDsY5DlpgCUWa_yWd9LthjdDGMA4M=w800-h1065-no


These look really ugly and I'm tempted to re-order the part but I'm also looking at what these hold and how the rest of the assembly goes together with two pieces of .125 bar, bolts, and a couple dozen rivets and I wonder if I'm being over-conservative.
I'd appreciate your thoughts.
I'd also appreciate a little help in understanding how I could do my level-best to keep the drill running straight and it still walk this much when drilling the .125 bar behind it. Any tips?

Greg
 
I?ve seen this with one builder who used an amazingly fast air drill. The centrifugal force on the bit when using a drill stop resulted in similar holes.

Any chance you used a bent drill bit?

Carl
 
Cordless drill

Carl,

Thanks very much for the reply. I was using a Dewalt cordless drill. Spins pretty fast but not nearly as fast as my pneumatic. I spun the bit and watched it a bit because I thought the same thing but it looks like there is very little run-out as it spins.
Could it have gotten dull and started wandering around? I haven't used it for that much and I use boelube.
What do you think about the viability of using this part vs replacing. I know the easy answer is replacing but I'm not sure it is necessary.

Greg
 
I don?t know the part so cannot vote on repair or replace. I can tell you if it bothers you just buy a new one. Most parts are cheap. Just make a list of stuff as you go so you do fewer but bigger orders as most shipping cost more than the part. USPS tends to be the least expensive.

Move on to the next area while you are waiting for parts.

Carl
 
The pictures did not come through for me but I thought I would chime in on some things to try.

Are the bits new? If they have been resharpened they might not be sharpened equally on both sides. Try some more bits on some practice pieces until you get it worked out.

Are you using split point bits. That is what I use, they do not seem to walk as bad.

Drill a little bit and check the point end of the bit to see if one cutting edge to holding a chip of metal. If it is the two edges will not cut equally.

If all the above checks out you might not be putting straight pressure on the drill.
Aluminum does not need a lot of pressure. Try putting the bit in a drill press if you have one and see if you get a round hole.

Let us know what you find out as someone else might be searching for the answer down the road and your post will help them as well.
 
Dull bit

Charles,

I'm thinking the bit is dull. It's a newer split point bit from Cleveland. I don't think I've drilled more than 20 holes with it, all aluminum. Can't imagine it is already dull but that appears to be the only answer that makes sense.
One additional point, As I was drilling the seatbelt anchors for AN3 bolts, they came out undersized. I checked the bit with calipers, .1885, the bolts are .1875 but the bolts definitely don't fit.
I've already ordered a couple new #12 bits so I'll try those. I'll also try putting it in a drill press and see what I can find.
I'll definitely post my results for others to learn from.
Sorry for those that can't see the pictures. I'm using google...seems odd that some can see and some can't. [ed. Google makes it harder to embed images. Just include a link so we can click as a plan B. v/r,dr]
 
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Reamers

As long as you're ordering bits, consider standard size reamers.
40, 30, 29, 19, 12 and 3/16, 1/4.
That covers #3, 4, #6 screw, #8 and AN3 & 4.
Always use a drill bushing and the smallest bit (#41) then enlarge and finish with the appropriate size reamer. Yes, most RVs were probably built without but a reamer hole fits perfect. Why not?
 
I would second what Larry says and add this: Never use a new, resharpened or otherwise "unknown" drill bit on your project without first testing it on a piece of scrap. You'll also find that most will drill a more accurate hole if a pilot hole is drilled first. As Larry suggests, a reamer is the most accurate, if you keep the aluminum from galling on it.
 
Drill bits are mass produced. They can be out of tolerance, not tempered, improperly sharpened, etc...
I feel the battery operated drivers spin to slowly for aluminum. Many have good success and I use one at times, but I prefer my Sioux at 2600 rpm.
 
Links don't work

Links don't work for me. I get a black page with a small circle and bar in the center of it.
 
Google photos won’t work for a hosting solution. They randomly change the path to the files and that makes it useless for this purpose. The link that does not change won’t work on this forum.
 
Google photos won’t work for a hosting solution. They randomly change the path to the files and that makes it useless for this purpose. The link that does not change won’t work on this forum.

Just wondering if you can see this? (I have been sharing google photos on here and so far I thought they were working). Just have to share the direct link (the right click open file link, not the link created by “share photo” etc - which it looked like the OP did).

GTZkS9gNxNyLqmaPdgMLbYEoC0IAQJT3LjkzyAM5V3HLiejLFCAXNZ5EVKObV-S74Io0qIuIHm_nSIEUxraH4SOpZDKR50VO62TlvxQwvx8iHd_v4PON-QUz05ZSI1Mus5-0FvRWdrKDp0OB8pYG7PRgRIm29X6G3CId5sc48QihgOR-X_vyK07oX87qD_hm-aBdLteCcP9kMNK3IOvTCNQhILQ696CM1ufiU9igXDiq8tRz_TI-nXXasrcWh99hNuNEyWuRyP8ZVcEj1zEp9fLw1TQ9ZHy6t7CfP_P8Yqf3UkPN3fL4094x33mozDePfQDDa-yY9ghsczNnTihOzkJ7Rrce70mubt8XxCipg3za_vjrv3aFQzuQf5JJ5KAAdDFi8rENvIxCQayv1o7GHc-T9KiMv9Zgbi74z4k9kOUjHyj1R6ccEWr1Uwm_JFp7G_AO_HfAQggxXSgHhho78IMqDJi_a2EecpvKX4GJCWDxyU1RPFk2DNp3Bnayc_2UhXU7exfaK5xiIf6pnw06NXZ6NiMLlZOJsAymRlR_SKHKF0I3Gc_ODE0fz4oDwSsv11vCJDB0w1f_PU92XWy5q6Dst8WJ_KnO6_31kXzPI21vXgwKK9Buh-SADuQpuJ8Co8IV1LdaZ1gqRJ-VIg2YmQf_ArmhGHLM_GhxVSgKx2OVhUtmhxTjGNGpFGmlfy-YBONqosk7T1pizwXH2jRKR74OAQ=w600
 
Just wondering if you can see this? (I have been sharing google photos on here and so far I thought they were working). Just have to share the direct link (the right click open file link, not the link created by “share photo” etc - which it looked like the OP did).

GTZkS9gNxNyLqmaPdgMLbYEoC0IAQJT3LjkzyAM5V3HLiejLFCAXNZ5EVKObV-S74Io0qIuIHm_nSIEUxraH4SOpZDKR50VO62TlvxQwvx8iHd_v4PON-QUz05ZSI1Mus5-0FvRWdrKDp0OB8pYG7PRgRIm29X6G3CId5sc48QihgOR-X_vyK07oX87qD_hm-aBdLteCcP9kMNK3IOvTCNQhILQ696CM1ufiU9igXDiq8tRz_TI-nXXasrcWh99hNuNEyWuRyP8ZVcEj1zEp9fLw1TQ9ZHy6t7CfP_P8Yqf3UkPN3fL4094x33mozDePfQDDa-yY9ghsczNnTihOzkJ7Rrce70mubt8XxCipg3za_vjrv3aFQzuQf5JJ5KAAdDFi8rENvIxCQayv1o7GHc-T9KiMv9Zgbi74z4k9kOUjHyj1R6ccEWr1Uwm_JFp7G_AO_HfAQggxXSgHhho78IMqDJi_a2EecpvKX4GJCWDxyU1RPFk2DNp3Bnayc_2UhXU7exfaK5xiIf6pnw06NXZ6NiMLlZOJsAymRlR_SKHKF0I3Gc_ODE0fz4oDwSsv11vCJDB0w1f_PU92XWy5q6Dst8WJ_KnO6_31kXzPI21vXgwKK9Buh-SADuQpuJ8Co8IV1LdaZ1gqRJ-VIg2YmQf_ArmhGHLM_GhxVSgKx2OVhUtmhxTjGNGpFGmlfy-YBONqosk7T1pizwXH2jRKR74OAQ=w600

I have found that they will work for some and not for others and Google will randomly change the link.

I can see it now but it likely won’t stay that way long term.

I thought Google was going to be the best thing ever since that is where I store photos but people started complaining to me that they could not see my pics. I used the same method you mention to get the link..... I switched to imgur and have been using it since. I would like to be able to use google to save steps but it has not been reliable for me.

PS. I checked the OP's links and they look like they are links that were created using your method you describe as well. The first day it was posted, I could see the pics but now I can't. Looks like Google changed the link.

The "share photo" button generates a link that looks something like this "https://photos.app.goo.gl/some random hash code here" This link never changes but it won't work for posting here on VAF.

The "right click and copy image address" method generates a link that looks something like this: "https://lh3.googleusercontent.com/some huge random hash code" This one seems to work for some and not for others and can get broken at any time Google decides to change the link.
 
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Thanks - interesting.

I?ll have to go back and look at old posts and see if any are gone. Could always post via blogger I guess.
 
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