To match drill or not?

[Lycosaurus]

It was interesting to hear on another thread, that some people did not match drill and deburr their parts, but went straight to dimpling and riveting. Maybe this poll will give us a glimpse as to the percentage or number of builders that went that route.

I, because I am me, match drilled, deburred, dimpled, washed, etched, alodined, and applied 2 part epoxy primer everywhere. I feel so foolish

I would be interested to hear from those that did not match drill/deburr, to see how many hours they have on the airframe, and if any cracks (or other related issues) have propagated from those holes.

Please, no flaming .... just the facts.

 

[DaX]

Drill, debur, dimple, rivet.

I am only scotchbrite-ing and priming places where two pieces of metal touch each other, and all non alclad parts (these also get acid etch and alodine).

 

[Mel]

Match drill what?

No holes came in the 1989 vintage kit! Not even lightening holes in the ribs. You guys have it tooooooo easy!

 

[Lycosaurus]

Relativity

No holes came in the 1989 vintage kit! Not even lightening holes in the ribs. You guys have it tooooooo easy!

Very true, but it's all relative, Mel.

I tell my quick-build buddy (he didn't even have to build the fuel tanks) that he had it so easy, compared to my "slo-build". He tells me his kit is so much more work than the "two weeks to taxi" program.

Then again, you had a kit... so much easier and faster to build than the RV-3 plans built from yesteryear.

 

[allbee]

On new pieces, I would strip the plastic, resize the holes with a reamer, than did a quick debur on the opposite side or rough side, dimple , hit the edges with a quick file, assembled the parts and riveted. I found that the prepunched kits are right on, once in a while I would find a rivet would not fit, I hit that hole with the reamer, then threw in the rivet and set it, than moved on. The only time I took things apart was when I needed to drill for new holes, I call this match drilling. I took the pieces apart to clean the garbage off on the opposite side of the drilling.

I did do a little priming in the back section, or tail. What I did there was clean the surface and hit directely with etch primer from Napa, no scotch brite.

 

[N941WR]

Even with as good as the pre-punch kits are, there is still some slight variation in the hole patterns. Match drilling aligns the holes and helps reduce stress between the rivets.

Will going straight to dimpling cause the plane to fall out of the sky. Nope but what no one really knows is the long term effect.

"They" say it will cause small stress cracks to form but I would wait to see a 2000 hour RV that was built this way before passing judgment.

However, since we don't have those 2000 hour match drilled RV flying around just yet, I would and did match drill, deburr, dimple, and then rivet as I hope to keep this plane a long time.

 

[airguy]

Even with as good as the pre-punch kits are, there is still some slight variation in the hole patterns. Match drilling aligns the holes and helps reduce stress between the rivets.

Will going straight to dimpling cause the plane to fall out of the sky. Nope but what no one really knows is the long term effect.

"They" say it will cause small stress cracks to form but I would wait to see a 2000 hour RV that was built this way before passing judgment.

However, since we don't have those 2000 hour match drilled RV flying around just yet, I would and did match drill, deburr, dimple, and then rivet as I hope to keep this plane a long time.

Same here - I'm limited by funds on my building time to somewhere around 3 years - so I've got time to do it right. That means drill, deburr, and prime all contact patches.

 

[Tkitchen1]

a little more on the drill vs punch conversation

Grettings all. when a piece of metal is punched, it tears out on the bottom side (die side) This tearing creates micro cracks at the edges. It also creates stress risers in the metal. Match drilling removes the punch tears and helps reduce the stess risers. Deburring remove the tiny little sharp edges that also have micro cracks. Although drilling does not remove all stress, It reduces probabilities. The second part of this equation is that when the rivet is set, it swells, if the hole is just big enough to get the rivet in, when it swells it could buckle or distort. All of this being said, all of the drilling and deburring does not eliminate potential cracks and failures, it just reduces the probabilities.

 

[rv7charlie]

When I started building, I made test samples using scrap pre-punched stiffeners.Some I dimpled 'raw', some I drilled/deburred/dimpled (with 3flute debur tool), some just deburred/dimpled. If you try it & examine each with a magnifier, I'll bet you'll be surprised at what you see.

I've heard that the RV-12 kit instructions just say to assemble & rivet (no match-drilling). Anyone know for sure?

Charlie

 

[Don Jones]

Combination here

I always drill, (ream actually), de-burr, dimple and sometimes I skip the match drill thing. Depends on what I am working on.

 

[robertahegy]

I drilled and deburred and made sure everything fit properly before riveting. That's what Van's intended and I agree. The new RV-12 has the holes to finished size and uses pop rivets that don't need dimpling.


Roberta

 

[rvbuilder2002]

I've heard that the RV-12 kit instructions just say to assemble & rivet (no match-drilling). Anyone know for sure?

Charlie

That is the process for the RV-12, but it has two major differences to the other kits.
The skin holes do not get dimpled, and blind rivets (which have less expansion pressure) are used.

 

[LifeofReiley]

The only way... match drill, debur, then countersink or dimple. This is the standard and MUCH preferred practice.

 

[Huck]

At the tail school they taught me to drill, then ream, then deburr & dimple.

Does anyone else drill and then ream?

 

[burgundyja]

you need another choice on the poles. drill, debur then debur again because you cant remeber what you already did last week then dimple, rivet, then drill out the rivets then rivet again and last have a beer. or 2

 

[allbee]

At the tail school they taught me to drill, then ream, then deburr & dimple.

Does anyone else drill and then ream?

The way I see it, you are doing a double duty. Second, by putting that drill bit in there first, you are messing up the hole. The reamer does a beautiful job and should be done as a stand alone. Now if you are doing a brand new hole, I would drill undersize than use the reamer to bring it to the right size.

 

[Kahuna]

You guys crack me up. Allow me to stirr the pot a little more.
1. There is a reason that the cracks introduced during the dimpling of these undersized holes will NEVER amount to anything. Do you know what it is?
2. There is a reason that the supplier of the materials undersizes these holes and wants you to follow the process they have laid out. Do you know what it is?


Rubber stamping a party line does nothing to further the discussion. Many RV have been built and flown for thousands of hours and did not follow the manufacturers reccommendations on MANY things. These kits have been further developed through the efforts on many that DID NOT follow anyone elses way of of doing things.

Discussing the merits of those deviations is a worth while cause. How about bringing science, facts, experience, and experiments to the table.

All in good fun.

 

[N941WR]

The way I see it, you are doing a double duty. Second, by putting that drill bit in there first, you are messing up the hole. The reamer does a beautiful job and should be done as a stand alone. Now if you are doing a brand new hole, I would drill undersize than use the reamer to bring it to the right size.

IMHO, this is overkill.

How many airliners, Cessnas, Pipers are built with just the standard drill and deburr method vs. drill, ream, and deburr? I would suspect almost all are done with just the drill & deburr.

 

[rvbuilder2002]

How about bringing science, facts, experience, and experiments to the table.

Good idea Mike...but you did none of those with the information you included in your post .

I know you have experience... but no one has experience with what will show up on an RV after 20 years when the pilot of a dimple die set has been driven into thousands of holes that it would not fit.

Once again going on record that I think dimpling without final drilling is a bad idea. This results in driving a die pilot into a rough sheared un-debbured hole (stretching it) and then dimpling it (stretching it more).

Match drilling...thats builders choice. Probably doesn't matter (most of the time )

 

[Webb]

Come on folks.....it's called MATCH DRILLING for a reason.

You have 2 different pieces of metal that have been punched and no guarantee they will line up 100% absolutely, without a shadow of a doubt, perfect. Guess what, you get a chance to make them mate nice and even.

Just for kicks and giggles, please be sure you put on the for sale sign that this plane has not been matchdrilled and see if your buyer still wants it.

 

[mackd]

You guys crack me up. Allow me to stirr the pot a little more.
1. There is a reason that the cracks introduced during the dimpling of these undersized holes will NEVER amount to anything. Do you know what it is?
2. There is a reason that the supplier of the materials undersizes these holes and wants you to follow the process they have laid out. Do you know what it is?

Care to enlighten us?

 

[N208ET]

Exactly Webb

There is a standard that applies here, and just about to everything. The standard way to do it is match drill, deburr, dimple or countersink. There is nothing wrong with going against the standard, heck homebuilding is pretty much against the standard of certified planes if you ask alot of people, but we as homebuilders have to placard our craft as EXPERIMENTAL. Put a decal on your plane that says EXPERIMENTAL and NO MATCH DRILLING AND DEBURRING WAS DONE IN THE BUILDING OF THIS AIRCRAFT. See if other homebuilding pilots who would usually ride with you decline the next invite. I for one don't have the experience to make a decision like to not drill and deburr, so I just went with the flow.

Randy

 

[dicel87]

Match drilling

Having not even begun a sub-kit yet I know I am woefully underqualified to jump in on this but I do have a question for those who have completed an RV or have one under construction.

Seems to me that the match drilling was certainly a very critical step before Vans began to use the CNC process to pre-drill holes. But now that the hole placements have been determined and aligned via CAD and already pre-drilled on the CNC machine, match drilling seems much less critical.

So what would be the downside of the following process...
1. Open boxes and remove blue plastic (all or some - as desired)
2. Drill out holes on all parts to final size
3. Deburr and edge prep
4. Dimple/CS
5. Prime (as desired)
6. Cleco assembly together
7. Rivet

 

[dhammer]

So what would be the downside of the following process...
1. Open boxes and remove blue plastic (all or some - as desired)
2. Drill out holes on all parts to final size
3. Deburr and edge prep
4. Dimple/CS
5. Prime (as desired)
6. Cleco assembly together
7. Rivet

haven't built an aircraft (yet), but spent a career working on them. I've pounded and pulled gazllions of rivets on most everything sized from Cessna to Boeings and some things I've done and some not.

1. Didn't try and final drill any two pieces separate then stick them together. Just because you run a bit through a hole doesn't mean the drill opened it up dead center of the punched one. Two or more pieces getting fastened together need to be drilled and dimpled together so they are concentric and aligned.

2. One way or another you have to de-bur, but no need to get paranoid about this. Just get the chips out that will keep the pieces from touching when you pound the rivet.

3. The only rivet hole I've ever reamed is for ones like a close tolerance Hi-Loc or similar. If you want to go that far then knock yourself out. I bet when Clyde Cessna was building thousands of 140's per year they didn't ream rivet holes and I bet Boeing doesn't either on highly pressurized 767's. Anymore its automatic machines drilling holes and shooting rivets.

Most of us aren't building rocket ships, so if you follow the manufacturer's recommendations and/or 43.13-1b you can't go wrong.

Build on

 

[Mel]

One comment here and you guys can have your thread back.

Van has spent years researching and designing airplanes and airplane kits. He has achieved arguably the best kits on the market. He has continually made them easier and quicker to build, almost to the point of making them less than 51%.
Why do you guys continue to try to short-cut the process?
Yes, experimental means experiment. But with design, not process. If Van says "match drill" then "match drill".
If you don't like the building process, then don't build!
Rant over. Continue.

 

[allbee]

There is a standard that applies here, and just about to everything. The standard way to do it is match drill, deburr, dimple or countersink. There is nothing wrong with going against the standard, heck homebuilding is pretty much against the standard of certified planes if you ask alot of people, but we as homebuilders have to placard our craft as EXPERIMENTAL. Put a decal on your plane that says EXPERIMENTAL and NO MATCH DRILLING AND DEBURRING WAS DONE IN THE BUILDING OF THIS AIRCRAFT. See if other homebuilding pilots who would usually ride with you decline the next invite. I for one don't have the experience to make a decision like to not drill and deburr, so I just went with the flow.

Randy

Way cool. Now if I don't want to take a pilot along fo a ride, all I have to do is say... I didn't match drill, oh! and lets put on there no primer as well. Since I'm going with the nose wheel, that aught to speak for itself.

 

[Rick6a]

My two cents.....

.....There is a reason that the supplier of the materials undersizes these holes and wants you to follow the process they have laid out. Do you know what it is?......

When building the -8 horizontal stabilizer, I accidentally riveted the left side skin on the right side of the stabilizer and did not discover the error until I went to rivet the remaining skin and noticed its part number sticker. Suddenly, I realized the error of my ways.

After a momentary panic coupled with a tirade of self chastisement, I went ahead and clecoed the right side skin on the left side and it seemed to fit perfectly. I went on the rivet that skin into place and in the process did not have to so much as wallow out one single hole. Not one. Matched hole technology is a true technical wonder certainly not anticipated when the amateur built regs were written decades ago. It worked out fine in my situation but some of you may remember the case of the RV builder who was not so lucky. He accidentally built two same side wings and did not discover the error until trying to mate those wings to the fuselage! Even Van's engineers as I recall were amazed the hole patterns generated on that CNC machine come in that precise.

l don't know why, as Kahuna asks us..... "the reason the supplier of the materials undersizes these holes and wants you to follow the process they have laid out" but I will hazard a guess as to why. I believe it is to enhance compliance with the 51% rule. That said, it is still a good idea to match drill per plans.....NOT because the airframe would otherwise fail at a zillion stress points as some would imagine but rather because Van directs you to. It may be among the many ways he is documenting and demonstrating to the FAA that you the builder are doing the lion's share of the work. In the process you are enhancing overall hole quality an indefinite degree. To my mind, that is always a good thing.....is it not?

 

[az_gila]

Some comments....

haven't built an aircraft (yet), but spent a career working on them. I've pounded and pulled gazllions of rivets on most everything sized from Cessna to Boeings and some things I've done and some not.

1. Didn't try and final drill any two pieces separate then stick them together. Just because you run a bit through a hole doesn't mean the drill opened it up dead center of the punched one. Two or more pieces getting fastened together need to be drilled and dimpled together so they are concentric and aligned.

Yes... but tolerances come into play here.... if Van has done his CAD drawings correctly, then I would guess that the CAM tolerances are in the 0.001 realm (does anyone have an exact figure?).
If we hand drill holes, I bet are tolerances are no better....
It comes down to the accuracy of the initial software representation, not the drilling process.

2. One way or another you have to de-bur, but no need to get paranoid about this. Just get the chips out that will keep the pieces from touching when you pound the rivet.

Yep... and even more important when the hole gets cold dimpled - the big factories will hot dimple the material.

3. The only rivet hole I've ever reamed is for ones like a close tolerance Hi-Loc or similar. If you want to go that far then knock yourself out. I bet when Clyde Cessna was building thousands of 140's per year they didn't ream rivet holes and I bet Boeing doesn't either on highly pressurized 767's. Anymore its automatic machines drilling holes and shooting rivets.

Yep... but in this case I don't believe we are talking about drilling holes (like Boeing) we are talking about punched holes from Vans factory - not an apples to apples comparison...

In our case, the effort to ream is identical to the effort to drill.... and I bet old Clyde Cessna never enlarged his holes by a mere 0.010 or so before rivet insertion, which is what we do. To remove this small amount, a reamer is actually easier to control than a sharp drill bit in thin sheets - and as I said, no extra work. Reaming is better...

Most of us aren't building rocket ships, so if you follow the manufacturer's recommendations and/or 43.13-1b you can't go wrong.

Definitely!

Build on

 

[rvbuilder2002]

haven't built an aircraft (yet), but spent a career working on them. I've pounded and pulled gazllions of rivets on most everything sized from Cessna to Boeings and some things I've done and some not.

1. Didn't try and final drill any two pieces separate then stick them together. Just because you run a bit through a hole doesn't mean the drill opened it up dead center of the punched one. Two or more pieces getting fastened together need to be drilled and dimpled together so they are concentric and aligned.

Yes... but tolerances come into play here.... if Van has done his CAD drawings correctly, then I would guess that the CAM tolerances are in the 0.001 realm (does anyone have an exact figure?).
If we hand drill holes, I bet are tolerances are no better....
It comes down to the accuracy of the initial software representation, not the drilling process.

And this is only speaking of one of the possible tolerance drifts. The punch machines have tolerance limitations. There are others as well. The expansion rate of aluminum is quite surprising. Join two different parts together that were punch on different temperature days and you have a drift of a few more thousandths. It all adds up to something. Some times that something is them canceling each other out, other times there is misalignment that will be corrected with final drilling.

 

[az_gila]

Working conditions...

...... The expansion rate of aluminum is quite surprising. Join two different parts together that were punch on different temperature days and you have a drift of a few more thousandths.......

Scott,

You mean Van does not have a temperature controlled shop for the punch machine....

Time to talk to the union foreman...

 

[rodcritt]

There is an answer

While I was clecoing on the skin of the HS, every 3-4th hole (thank you DR), I came up to the leading edge at the 706 Rib Tip. There is a hole for match drilling in the skin that is not in the rib. So this is a drill in assembly hole. If I had not match drilled and gone on to prime, debur, dimple, whatever I would have been drilling out rivets just to dimple one rib hole. Yes it is in an easily accessed place but what if it was somewhere else.
Many of you have the experience to foresee this type of thing. It just goes to show you there are areas where not match drilling could be a problem.

 

[sprucemoose]

Some times that something is them canceling each other out, other times there is misalignment that will be corrected with final drilling.

Scott knows of what he speaks (duh! he should!) On the right elevator on my -8, I gleefully clecoed the whole thing together, match drilled, deburred, primered and riveted it together, all the while thinking how easily the whole thing went together. Only when it was all riveted up did I notice that the trailing edge had a distinct banana shape to it. There was probably 3/8 inch of bow along the trailing edge, owing to imperfections in the placement of the prepunched holes and/ or the bends of the parts.

I drilled out most of the rivets, jigged it up in my trusty old -6 tail jigs (good thing I saved those!) but the thing was too far gone to save, so it is now scrap.

Matched hole is great stuff, but I think the incidence of imperfect parts is higher than you might think. It is still worth your time to check allignment before committing drill to metal. Makes me long for the good old days of non-prepunched anything!

 

[Lycosaurus]

Do not deburr before dimpling ??

Just found this from page 94 from the Standard Aircraft Handbook for Mechanics and Technicians:

Hole Preparation for Form Countersinking ​

Preparation of holes for form countersinking is of great importance because improperly drilled holes result in defective dimples. Holes for solid-shank rivets must be size drilled, before dimpling, by using the size drills recommended for regular holes. Holes for other fasteners must be predrilled before dimpling, and then drilled to size, according to the blueprint or applicable specification after dimpling. Do not burr holes to be form countersunk, except on titanium.​

Note: form countersinking = dimpling

 

[RV7]

I read the same thing...

Just found this from page 94 from the Standard Aircraft Handbook for Mechanics and Technicians:

Hole Preparation for Form Countersinking ​

Preparation of holes for form countersinking is of great importance because improperly drilled holes result in defective dimples. Holes for solid-shank rivets must be size drilled, before dimpling, by using the size drills recommended for regular holes. Holes for other fasteners must be predrilled before dimpling, and then drilled to size, according to the blueprint or applicable specification after dimpling. Do not burr holes to be form countersunk, except on titanium.​

Note: form countersinking = dimpling

I read this too, and now wondering if I am wasting time deburring every hole that will be countersunk.

 

[GAHco]

Best of both Whirls, pun intended!

On my slow build 6 kit the tail had no holes in any of it.

Pre-punched was only a dream.

On the wing only the skins came Pre-punched, and that's the way I like it.

I got to put the rib holes in with the skins held in place, and what do you know, they matched up perfectly and ALL the holes were cleaned up with a nice high quality drill bit.

I am up to my fuselage kit now (I got it about 15 months ago) and NOTHING has holes in it except for the pre-punched firewall and its associated parts.

Back to the Stone Age.

Either join the club or bring one!

 

[GAHco]

Things that make you go HMMM!

I read this too, and now wondering if I am wasting time deburring every hole that will be countersunk.

It is my belief that they're are calling what we call a "countersink bit" a burr.

Once again my belief is that they do not recommend countersinking an already formed dimple any further with a "countersink bit" or on archaic aircraft language a "countersink burr".

They allow this on Titanium because of the increased amount of spring back.

To help with that extra spring back at some point, they even made heated dimple dies

 

[swift12]

im reopening this discussion because i am tired of clecoing every **** hole to ensure alignment...bottom skin to seat ribs....fairly tight fit to get clecos in.....yes i have de burred....yes i have flanged and fluted...everything perfect.....match drill....get 20% of the holes elongated...yes i used a reamer....im inclined to just ream the holes and dimple...because everyone thinks you are cleaning up the holes but there is only 6 thousandths of an inch to clean up..the punched holes are .092 and the number 40 reamer is .098. thats only 3 thousandths of an inch each side of the hole.....but somehow...some of the holes just wont play ball....i have a tool to ensure all holes are in alignment after fluting....yes the flanges are 90 degrees....some of the seat ribs have elongation to max spec (.103) and some over that....only a few...the worst is .111....frustrating when you take all the time and care to ensure its checked to the max....still get oval holes at times...

 

[Jonnyb]

If it’s a pre punched kit I’m not sure there is a need to match-drill anymore.

In theory you should be able to order replacement parts from the factory and put them straight on the aircraft after only final sizing and dimpling.

 

[swift12]

Grettings all. when a piece of metal is punched, it tears out on the bottom side (die side) This tearing creates micro cracks at the edges. It also creates stress risers in the metal. Match drilling removes the punch tears and helps reduce the stess risers. Deburring remove the tiny little sharp edges that also have micro cracks. Although drilling does not remove all stress, It reduces probabilities. The second part of this equation is that when the rivet is set, it swells, if the hole is just big enough to get the rivet in, when it swells it could buckle or distort. All of this being said, all of the drilling and deburring does not eliminate potential cracks and failures, it just reduces the probabilities.

Interesting to be reading this now in light of LCP…..because it appears all these fears were completely unfounded! It’s ok to build with cracks all over the place…
Plus match drilling only takes 6 thou out. If the hole is misaligned 3 thou then the reamer licks the side of one hole and takes 6 thou out of the other….this is a common occurrence no matter how well clecoed you are….so what’s worse? Holes a few thou out or big holes? I’m guessing both but I haven’t found enough inaccuracy in the punched items as yet and if I did I bet it’s more than three thou and won’t necessarily clean up with a lick of the reamer.

 

[swisseagle]

It depends on which kit you have ...

Not ALL parts have the final size hole pre-punched!

So check with a rivet first, if you need to match-drill or nut.

Anyway, deburring before dimpling is recommended.

 

[rocketman1988]

…and

It depends on which kit you have ...

Not ALL parts have the final size hole pre-punched!

So check with a rivet first, if you need to match-drill or nut.

Anyway, deburring before dimpling is recommended.

…and most builders seem to go way to far with debuting; you are supposed to remove the burr, not countersink the hole…

 

[airguy]

…and most builders seem to go way to far with debuting; you are supposed to remove the burr, not countersink the hole…

+1.

Here's a hint - if you're using any type of power tool to deburr, you're doing it wrong.

 

[swift12]

It’s an rv 7. Pre punched not final size. So all holes need to be reamed. Nothing about de burring is an issue. It’s about match drilling and elongating holes

 

[cgarts1]

Wrong vote

I realized after I voted that I did not match drill/deburr that this thread was about under sized holes and NOT the final sized holes that Vans instructions specifically say are ready to be dimpled. I've never forced a dimple die through a hole. I'm surprised that this even a thing.

 

[KatanaPilot]

Direct to dimple has been done even with undersized holes under certain approved conditions. This was discussed in this thread. Was a pretty big time saver. Be sure to read the entire thread.

 

[PilotjohnS]

Not me

Direct to dimple has been done even with undersized holes under certain approved conditions. This was discussed in this thread. Was a pretty big time saver. Be sure to read the entire thread.

When I tried to dimple undersize holes (not reamed to final size) they would crack. But now that Vans is final sizing today's kits, I guess it is different.

 

[wirejock]

Drill or ream

Wait. The original post says "Match Drill".
I reamed, deburred and dimpled.
That's another thread. Kinda like Primer Wars.
Oh bother.
The world needs more funny

 

[Ironflight]

im reopening this discussion because i am tired of clecoing every **** hole……

I’d be really careful with whatever conclusions you draw from this poll because it was started in 2008 when kits were considerably different than they are now! It would honestly be far better to start a new poll and state which kit you’re interested in - the RV-3/4/6 are very different from the RV-7/8/9, which are completely different than the -10/12/14….and some of those differences change with the year of manufacturer of the kit.

Mixing all that up, along with the differences in years makes the data just….mush.

Paul

 

[swift12]

I’m not drawing conclusion from this poll….I don’t try to push dimple dies through an undersized hole. I’m specifically interested in reaming to final size….and then dimpling…then putting it together….the small variances at times might make the holes perfectly aligned but at other time it just elongates holes….and the6 become larger than spec.

 

[FMF15E]

Started on RV-10 Oct 2023

As a repeat offender, I previously built an RV-8 slow build with some prepunched (wings and tail) and some non-punched (fuse). All holes in the RV-8 were drilled or match drilled and then deburred before dimpling.
Now, almost 20 years later, my RV-10 build has final sized holes. I have found that match drilling is an essentially useless task as the drill almost always does not remove any metal from my clecoed structure. I have performed the match drilling as it is in the instructions, but I question the utility. After match drilling and disassembly, deburring is really only needed on the side of the exit of the punch.
I welcome this thread and will follow as I was just thinking through this idea myself.
FM