Getting holes EXACTLY in the middle?

[exx1976]

Ok, guys, I'm about at my wit's end with this.  I think I've managed to solve for just about everything EXCEPT this problem here.

 

To date, other solutions I've come up with to make this process repeatable are (AKA some lessons I've learned):

Created a jig for my router table to hold wood blocks to shape the lures with a flush trim bit after a rough cut on the band saw.
Use a roundover bit on the router table so the backs and bellies of the baits are exactly the way I want them (was doing this by hand, but WAY too slow).
Drilling the pilot hole for the eye all the way through the lure to ensure the eyes are in the exact same spot on both sides.
Setting the stop on the drill press when using the forstner bit to drill the eye sockets and ballast holes.
Using a miter attachment on the band saw to get the angle of the lips EXACT every time (bonus that the kerf from one saw cut is the exact width for a snug fit of the lip I'm using).

 

But, there's ONE problem I still can't figure out how to solve, and that is how in the world to get the holes for the screw eyes in the EXACT middle of the bait?  When I started, I was drawing lines all the way around the bait, while it was still blocky, to define the exact center, and then I was using the drill press to drill holes on that line.  Depending on how many cups of coffee I had that morning, I may have been pretty darn close - or not.

So I says to myself I says "Self, there's got to be an easier way".  That's when the perfectionist in me took over, and started looking at way to engineer a solution to the problem.  So, I bought one of these:

https://www.amazon.com/gp/product/B0826YXY39/ref=ppx_yo_dt_b_asin_title_o00_s03?ie=UTF8&psc=1

I also bought some stainless steel tube that was JUST barely big enough for my drill bit to fit in (my math says the tube is about .006" larger than my drill bit).

So, the contraption arrived, and it's too wide.  I didn't read the description, and it only work on pieces as narrow as like 17mm or something.  Mine are about 13mm.  Ok, so I'll use some acrylic sheet, CA glued to the "arms", to shim it, like this:

 

Splendid.  That appeared to solve that problem.  It now closes firmly on my blanks.  Now, to craft the pilot for the drill bit!  I took the stainless tubing, wrapped masking tape around it until I got a snug fit in one of the guides from that thing, jammed it in TIGHT, then stuck it in the vise, and cut off the excess tubing with a hacksaw, flush to the bottom of the guide.  Put the guide in the jig, stuck it in the drill press, and drilled out the flash from the cut.  Then I countersunk the top of it to make it a bit easier to guide the drill bit into, like so:

 

Sweet!  This should be super easy!!!  So I grabbed a blank, stuck the jig on it, stuck it in the drill press, and sunk a hole:

 

 

In case the photo doesn't CLEARLY show it, the hole is off center by .010".

In my head, I know how to fix this, but I'm stuck on the fact that it didn't work correctly the FIRST time.  A considerable amount of thought, time, and effort went into all this, and I really thought I had it licked (I'm much more perfectionist than I am engineer).

So I ask the group two questions:

How important is it that the hole be in the EXACT center?  Is .010" off center that big of a deal?  I guess I never busted out the calipers and measured any of the baits in my boat.  LOL

Second, how do YOU get the holes or eyes in the dead center of your baits?  Or don't you?  Do you just eyeball it and call it good enough?

 

Am I making a mountain out of an ant hill here?  HELP!!!

 

Thanks,
exx

Edited December 13, 2020 by exx1976

[Vodkaman]

Belly holes are generally not such a big problem, the BIG issue is the nose and tail holes, and the reason for this is that you are drilling into end grain. The grains have their own direction, so the hard and soft layers are going to pull at your drill bit. It is a ‘path of least resistance’ thing.

Always start the hole with a bradawl point. Pull this around until it is perfect. Start the hole with a 1/16” diameter bit in REVERSE direction, going in about 3/8”, all the time eye-balling to make sure I am dead on. Then go to final size, reverse spin for the first ¼” and then normal drill the rest of the depth.

Reverse direction is not good for the drill bit, so it is best to keep these bits separate just for that job.

Reverse starting serves two purposes;
1 – It prevents chipping the wood at the start.
2 – It gives you great control over progress, it will not grab and pull into the wood.

Of course, I should not have to mention sharp bits for the job, and keep the bit extension from the chuck as short as possible, particularly with small diameters.

Personally, I drill all my holes and slots in the square block before carving.

Dave

[exx1976]

2 hours ago, Vodkaman said:

Belly holes are generally not such a big problem, the BIG issue is the nose and tail holes, and the reason for this is that you are drilling into end grain. The grains have their own direction, so the hard and soft layers are going to pull at your drill bit. It is a ‘path of least resistance’ thing.

 

Always start the hole with a bradawl point. Pull this around until it is perfect. Start the hole with a 1/16” diameter bit in REVERSE direction, going in about 3/8”, all the time eye-balling to make sure I am dead on. Then go to final size, reverse spin for the first ¼” and then normal drill the rest of the depth.

 

Reverse direction is not good for the drill bit, so it is best to keep these bits separate just for that job.

 

Reverse starting serves two purposes;
1 – It prevents chipping the wood at the start.
2 – It gives you great control over progress, it will not grab and pull into the wood.

 

Of course, I should not have to mention sharp bits for the job, and keep the bit extension from the chuck as short as possible, particularly with small diameters.

 

Personally, I drill all my holes and slots in the square block before carving.

 

Dave

 

While I appreciate the detail in your answer, it didn't really answer my question.  You provided a splendid description of how you drill the hole, but you didn't tell me how you manage to get the hole in the exact center, or how you find the center, for that matter.

As for the bit being pulled, the jig would prevent that - or at least, it would only allow it to be pulled up to .003" off-center.  The jig clamps onto the flat sides of the bait, not the curved back or belly portions (which would be the only way the lure could "slide").  I'm holding the jig tight, and using it to hold the bait upright, so the jig isn't opening up or coming loose or anything like that.

Edited December 14, 2020 by exx1976

[Vodkaman]

I will scribe parallel lines around the square block and eyeball the rest of the way. Just as in your original post, you can see that the hole is not centered. I use my eyes to fine tune the start of the hole, get it right, then drill through. Pretty much as I described above.

Dave

[exx1976]

Just now, Vodkaman said:

I will scribe parallel lines around the square block and eyeball the rest of the way. Just as in your original post, you can see that the hole is not centered. I use my eyes to fine tune the start of the hole, get it right, then drill through. Pretty much as I described above.

Dave

Gotcha.

 

I'm really looking for something that more repeatable, faster, and precise than eyeballing it.  I'd like to start MAKING lures, not just "making" them.  The immediate goal is to replace all the plastic lures in my boat with wooden ones that I've made, and I have more than a handful.  LOL

No idea where it will go from there, but this I know for sure - my present processes are much too time consuming for this to ever be more than just a hobby (the amount I'd have to charge as related to the amount of time invested would be something not many people would be interested in), hence the search for repeatability and speed in all aspects of the process.

[Vodkaman]

It certainly takes a lot more time to write about it than to actually do it, but I do see your point. Getting the holes right is more tedious than time consuming.

For many builders it is not about the time at all, it is about quality and craftsmanship. I am NOT one of them. For me, right from day one, it has always been about the time, and I accept that the quality builders are going to look at me with a little contempt, but that is OK.

A jig is the only answer to repeatability, but the problem with hand carving is that you cannot build a neat fitting jig because of the carving variations, at least, I have not come up with the solution. This is why I drill first and carve later. If I screw up the holes then I can start again with minimal loss of time.

When I built the duplicator then things changed. The bodies were constant and jigs could be made, I had templates and jigs for everything.

Dave

[exx1976]

2 hours ago, Vodkaman said:

It certainly takes a lot more time to write about it than to actually do it, but I do see your point. Getting the holes right is more tedious than time consuming.

For many builders it is not about the time at all, it is about quality and craftsmanship. I am NOT one of them. For me, right from day one, it has always been about the time, and I accept that the quality builders are going to look at me with a little contempt, but that is OK.

A jig is the only answer to repeatability, but the problem with hand carving is that you cannot build a neat fitting jig because of the carving variations, at least, I have not come up with the solution. This is why I drill first and carve later. If I screw up the holes then I can start again with minimal loss of time.

When I built the duplicator then things changed. The bodies were constant and jigs could be made, I had templates and jigs for everything.

Dave

Oh, I'm all about quality and craftsmanship as well.  But in my eyes, a BIG part of the "quality" side of the equation is that if one bait I make runs awesome, then the next bait should run equally as awesome, not have variations from example to example.  That means either LOTS of time, and actual water testing of every single example; or it means having repeatable ways to accomplish repetitive tasks.  My ultimate goal is that the only variation lure-to-lure is the paint job.  I want the holes in the same spot, I want the weight in the same spot, I want the same amount of weight, I want the lips all identical and at identical angles, etc.  The lures are still hand made, insomuch as my hands touch them at every single step, they aren't being produced by machine in some automated process the way a mass-produced, "modern", injection-molded lure would be.

I do not see jigs and router tables as a crutch or as a detractor to custom work, but rather, I see them as tools that enable me to repeatably produce high quality lures as efficiently as possible.  Every mistake I can eliminate helps to eliminate waste, which keeps costs down.  If this ever becomes more than a hobby, waste is a very important consideration.  Every minute(s) I can shave from some monotonous process allows me that much more time to spend on painting, and on getting perfect epoxy.  There are only so many hours in a day, and with having a regular full-time day job, there's only so many hours left to go around.  Further, this is (planned to be) only a winter hobby for me at this point; I'd like to make as many lures as I can before the ice melts again - when I'd rather be using them than making them.

Edited December 14, 2020 by exx1976

[Travis]

4 minutes ago, exx1976 said:

My ultimate goal is that the only variation lure-to-lure is the paint job. 

Easy....  You have to invest in machinery and tooling and take the human element out of it.

 

[exx1976]

1 hour ago, Travis said:

Easy....  You have to invest in machinery and tooling and take the human element out of it.

 

Hrmmm..  At that point, "removing the human", I think is a bridge too far in saying a lure is "hand made" or "custom made".  Jigs for repeatability, wielded by humans, are one thing.  But to mechanize the entire process, and "remove the human", well to me that's just a "production lure".

I may be a bit pedantic, but these personal delineations will become ethics problems for me later should I end up being good at this, and decide to begin selling some.  I'm not the type that could take a mass-produced product and sell it as "custom" or "hand made" and not feel dirty or bad.  Since I don't enjoy feeling that way....

 

I have two spinning on the epoxy turner now.  They should have the requisite amount of ballast in them based upon VodkaMan's spreadsheet (and I did, in fact, float an example with the same ballast).  One has a TINY bit more ballast than the other (.25"x.4" hole), added to the back of the lure, just to see how it affects action (but well within spec on the spreadsheet).  Otherwise, they are identical (with the possible exception of screw eyes not being exact - I didn't have my jig yet).  I plan to add both of them to my personal collection unless they are so abysmal that they turn into just another lesson.  Going to put the final coat of epoxy on them before I go to bed tonight, and hoping to be able to sneak away to a local hotel pool Tuesday morning for a quick test and video - work schedule depending.

 

I did fix the jig, in case anyone is interested.  4 layers of masking tape on one of the pieces of acrylic just to shim it out a tiny bit, and the holes are now so centered that I am unable to discern a difference with a digital caliper and the naked eye.

Edited December 14, 2020 by exx1976

[Travis]

I was just pointing out if you truly want the only variable to be the paint you can not succeed by doing it by hand.  Even machinery screws things up.

I use jigs, stops, etc.. just like you to reduce time and more reliably replicate lures if needing to make a lot of something.  To be honest we are removing ourselves from the equation as much as we can.      We are just the cheap labor on the  production line.  

 

 

[exx1976]

1 minute ago, Travis said:

I was just pointing out if you truly want the only variable to be the paint you can not succeed by doing it by hand.  Even machinery screws things up.

I use jigs, stops, etc.. just like you to reduce time and more reliably replicate lures if needing to make a lot of something.  To be honest we are removing ourselves from the equation as much as we can.      We are just the cheap labor on the  production line.  

 

 

True enough, I suppose.  But mentally, I am able to tell myself it's "custom" or "handmade" if mine are the only hands making it.  If I start hiring the neighborhood kids to run my router table and drill press, it then becomes more of a production endeavor.  Again - pedantic, perhaps.  I suspect many builders who make custom lures do similar, though.  I know of several builders that sell VERY expensive lures (multiple hundreds of dollars each, with only ~500 examples produced annually) that either have YouTube channels, or have been filmed for various outdoors channels.  They all used some type of jig to replicate at least portions of their operation.  In fact, the flush trim bit/router table/template idea I got from one of their videos.  Previously I was rough cutting and then finishing to spec on a belt sander.  OYE, what a tedious process, and didn't always produce perfectly square surfaces.  The router table will be MUCH better.  I'm just waiting on my bottom-bearing flush trim bit to arrive so I can put it to the test.

 

[Travis]

Can always jump to the dark side and mold your lures if you want to really get down to replication.  I never enjoyed the process as too much like stamping widgets.

 

[exx1976]

2 hours ago, Travis said:

Can always jump to the dark side and mold your lures if you want to really get down to replication.  I never enjoyed the process as too much like stamping widgets.

 

Negative.  The whole purpose I started on this adventure is because I can buy all the plastic baits I want, but all the good ones, the ones that USED to be wood, are now plastic.  So I want to make wooden ones because plastic sucks.  LOL

[Vodkaman]

Exx1976 - I think you are going to have to find another word to use in place of 'custom'. This is a word that is incorrectly used on this site and probably throughout the industry.

A custom lure is one designed and built to a particular customer's specifications, and the lure is sold ONLY to that customer. If you sell that lure to other customers then it is no longer a custom lure. I fall about laughing when I see an internet site stating; custom lure, three left in stock!

Ethics is good subject, but the ethical boundaries are self imposed rules and cannot be imposed on another builder as a fact, it is merely your opinion. A group can scream and shout against a drug company's use of human placenta material used to make a life-saving drug, but again, it is only the group's opinion, the people whose lives depend on that drug to live might possibly have a different opinion.

If I choose to build my lure bodies with a duplicating machine, finish with a flap wheel, drill the holes with a drill press and a store bought drill bit, cut the lip slots with a band saw, paint using an airbrush and use a lure turner to get an even coat, make no mistake, those lures are hand made. Why? Because I controlled the shape of the lure, determined the position of the holes, slot and  ballast locations and I operated all those tools.

Even if I have a line of villagers doing the work for me, the lures are still hand made, I taught them how to do the jobs, the jobs are done to my specifications, the inspector works to my standards, right down to the packaging.

Personally, I would never get involved with any of these contentious adjectives, I would design a lure to work a specific way, build it by whatever means and sell it. The customer would understand that this lure is unique and totally original, and every lure will perform to my specification.

I would set the price according to materials, labour and an acceptable profit. I would not indulge myself in justifying my price with such words as custom or hand made or made in Indonesia. Either the customer wants to fish my lure and is prepared to pay the price or they are not.

Dave

Edited December 14, 2020 by Vodkaman

[exx1976]

33 minutes ago, Vodkaman said:

Exx1976 - I think you are going to have to find another word to use in place of 'custom'. This is a word that is incorrectly used on this site and probably throughout the industry.

A custom lure is one designed and built to a particular customer's specifications, and the lure is sold ONLY to that customer. If you sell that lure to other customers then it is no longer a custom lure. I fall about laughing when I see an internet site stating; custom lure, three left in stock!

Ethics is good subject, but the ethical boundaries are self imposed rules and cannot be imposed on another builder as a fact, it is merely your opinion. A group can scream and shout against a drug company's use of human placenta material used to make a life-saving drug, but again, it is only the group's opinion, the people whose lives depend on that drug to live might possibly have a different opinion.

If I choose to build my lure bodies with a duplicating machine, finish with a flap wheel, drill the holes with a drill press and a store bought drill bit, cut the lip slots with a band saw, paint using an airbrush and use a lure turner to get an even coat, make no mistake, those lures are hand made. Why? Because I controlled the shape of the lure, determined the position of the holes, slot and  ballast locations and I operated all those tools.

Even if I have a line of villagers doing the work for me, the lures are still hand made, I taught them how to do the jobs, the jobs are done to my specifications, the inspector works to my standards, right down to the packaging.

Personally, I would never get involved with any of these contentious adjectives, I would design a lure to work a specific way, build it by whatever means and sell it. The customer would understand that this lure is unique and totally original, and every lure will perform to my specification.

I would set the price according to materials, labour and an acceptable profit. I would not indulge myself in justifying my price with such words as custom or hand made or made in Indonesia. Either the customer wants to fish my lure and is prepared to pay the price or they are not.

Dave

Excellent points, all.  I will be certain to re-read this reply if and when the time comes that I sell any.

About the only part that gets onto the edge of my own personal ethics is the line of villagers bit.  To me, that feels a bit too much like an assembly line, and I don't know as Henry Ford advertised the Model T as being "hand made".  LOL

Ultimately, you are correct though.  Make a quality product, set your price, and either people want it or they don't.  I have many more bridges yet to cross before I reach that one, however.

[Vodkaman]

Yes indeed, it definitely would be an assembly line. But with customers demanding 5,000 products per week, what choice do I have. But, the lures are still made by hand. Regardless,  no ethical dilemma exists as I never called my lure 'hand made' in the first place

'Hand made' is a meaningless statement. The price is the price, according to materials, labour and profit. The REAL ethics comes in when you are over-charging for a product, but even this can be justified by supply and demand, that is until the Chinese get a hold of your design.

Dave

Edited December 14, 2020 by Vodkaman

[exx1976]

1 minute ago, Vodkaman said:

Yes indeed, it definitely would be an assembly line. But with customers demanding 5,000 products per week, what choice do I have. But, the lures are still made by hand. Regardless,  no ethical dilemma exists as I never called my lure 'hand made' in the first place

Dave

If you have a demand of 5,000 pieces per week, you can call your lures anything you want!  LOL

[Outlaw4]

One way you can mark the center lines perfectly accurate, or as accurate as your tools is to use a height gauge scribe. Before laser cutters this is how we laid stuff out in metal fab. You need a good level surface and the gauge. 

One other thing i tried was laminating two sides, this also gives you a nice center line. Trouble i found there was that the laminating epoxy i was using was more difficult to drill into than the wood so it was also difficult to stay on line.

Now i kind of like to roll with laminated thru wire. 

IF...you had all the other processes down, you'd just have to add the wire bending and gluing stage but those are very productionable steps

[exx1976]

2 hours ago, Outlaw4 said:

One way you can mark the center lines perfectly accurate, or as accurate as your tools is to use a height gauge scribe. Before laser cutters this is how we laid stuff out in metal fab. You need a good level surface and the gauge. 

One other thing i tried was laminating two sides, this also gives you a nice center line. Trouble i found there was that the laminating epoxy i was using was more difficult to drill into than the wood so it was also difficult to stay on line.

Now i kind of like to roll with laminated thru wire. 

IF...you had all the other processes down, you'd just have to add the wire bending and gluing stage but those are very productionable steps

I'm considering this for future iterations of the lure.  It wouldn't be that difficult, I already have a really nice resaw blade for my bandsaw that makes light work of slicing wood.  But, since I don't currently have a thickness planer in the shop, getting those two pieces of the lure perfectly flat and mated back up would prove a challenge.  Perhaps that will be next winter's project.

[Big Epp]

When creating handmade baits out of wood some variation is always present, as there are different grain patterns, hard and soft spots in wood, and all sorts of variables.  When I worked in a lumberyard we used to tell people, "you show me a tree without branches and I'll show you a board without knots..."

I kind of like the variability.  It comes with the territory and adds an element of nostalgia.  After finishing a bait (and I test each one several times throughout the creation process) I'll take it to a pond and take several casts, varying retrieve speeds and other things to test its function.  That way each bait is "tested to ensure proper action."

I like the idea of using calipers to find a perfect center, but I've had really good success eyeballing it.  

Might not be custom, but "handcrafted," has a pretty good ring to it.

Lots of really helpful ideas on this thread!  Thanks all for the input.

[eastman03]

Great thread- from ethics to drilling holes.  Cover just about everything!     

As far as making consistent repeatable lures down to .01" differences (wow!), you may have to reconsider using wood.  I agree with Big Epp, using wood will always have some variables that we cant totally control.  I have made batches of 12 crankbaits for a while now, and kept them the same to the best of my ability, and had one or two swim slightly different (sometimes better, sometimes worse).   There are options like certain plastic deck boards (see other form posts) that would allow you to work as though it is wood, but take the variability of wood off the table.  Just a thought, I like wood, and it suites me good enough.

I have never been too concerned with tolerances of .01", but I make larger lures, and smaller batches, so I understand the need for repeatability.  

As far as ethics go, it is the eye of the beholder often, so it can be tough.  I remember an old form post on muskiefirst when everyone was up in arms after a lure maker wanted to make a pin/clevis style lip, similar to a Headlock bait (which are very popular and expensive).  Well everyone thrashed this poor fellow for wanting to emulate an idea of a bait.  It wasn't until someone posted a lure that was from much before Headlock's time with the same pin/clevis lip design, it kinda quited down. 

I had one couple I guided order two different truly custom lures from me.  I think his wife loved the idea of having a private Canadian lure maker, so she could show off a custom lure at bass tourneys and make other guys wonder where she got that? lol.  That is what her husband said.  haha  She told me to charge more for my lures, there is a lot of people with a lot of money, and they think they are worth more if they pay more, and want it even more.  haha Oh man, she was a strong confidant woman from Texas.  I should have hired her to sell for me. Anyway, sorry for getting off topic lol.

[Travis]

The handmade/custom thing is all over the board.  I don't get too caught up in it and am more  concerned about is it a good bait. 

I enjoy woodworking and this sort of topic pops up frequently.  I can hand cut dovetails, I can use some of the common dovetail guides that hold the saw at a given angle, or I can use my router and jig.   I can get the same results using all three methods just the time needed for each differs. 

A solid clean hand cut dovetail impresses me  the later not so much but yet they all perform the same function.   One takes more skill and ability and we go down to one takes an average functioning person. One I will pay more for as I understand the craftsmanship/skill behind the product (view it as translating to the entire project) the other I typically would pay less for as it was built by an assembler. 

Some lure makers frequently cross back and forth across that line and go from being a craftsman initially to an assembler once we get the jigs and process in place.   Some are always assemblers.  

 

Edited December 15, 2020 by Travis

[SlowFISH]

As many have said- repeatability with "hand tools" - even that jig you worked on is a "hand tool" as far as I'm concerned - and is going to have a much large variance in tolerance than using "machining /fixture clamping" type processes.  I have a benchtop CNC mill - and I still get variances if I turn up the speed and if I haven't tuned/dialed in the backlash and stuff in awhile - that's just machine tolerance - never mind trying to keep accuracy drilling with tiny bits.  That's basically a long way of saying doing things by hand even with jigs/fixtures will always have some tolerance - notably with wood which has a grain and with small diameter drill bits inevitably lead to some wandering and misalignment. 

What I'd recommend are (3) things to help with the holes...

1. Use a drill press and vice... holding something with you hand will never give you great repeatability.  Assuming your drilling more than one bait at a time and they are the same thickness... you set your vice up and drill all the holes on a number of baits - this will minimize variance between baits to some degree provided you setup fixtures/stops to insure each bait is placed into the vice the same each time.

2. Use a center drill to start the hole.  You'll need to use a drill press or make your jig able to swap in different dia. bits.  Center drills are WAY more rigid than a .02-.04 diameter drill bit.... once you have a pilot hole from the center drill - you can then swap it out and go deeper with a standard drill bit as necessary and USUALLY keep things straight.

3. They sell small "X / Y" tables.... which basically allows you to "convert" your drill press into a makeshift mill with a vice.  The benefit here is once you line you table up parallel on the drill press - you can drill multiple holes in one axis all on the same center line fairly easy - for something like a jerkbait where you have multiple hook hangers.  On a crank might no be worth the effort

  One off amazon - not sure of quality/usability.

https://www.amazon.com/MultifunctionWorktable-Milling-Compound-Drilling-Adjustment/dp/B07DK8JJ16/ref=sr_1_3_sspa?dchild=1&keywords=xy+table&qid=1608046049&s=hi&sr=1-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExSTFWN0tHNEhXVlVIJmVuY3J5cHRlZElkPUEwMTc3OTYxMzNWT01HMUpSOEZGSSZlbmNyeXB0ZWRBZElkPUEwMDEyNTE0MUdMM0FGNjBRQjJZNCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

Work on jigs/fixture you can clamp down on tool like drill presses - that's only way you'll get repeatability/accuracy if that's your concern.

 

  J.

 

[exx1976]

35 minutes ago, SlowFISH said:

As many have said- repeatability with "hand tools" - even that jig you worked on is a "hand tool" as far as I'm concerned - and is going to have a much large variance in tolerance than using "machining /fixture clamping" type processes.  I have a benchtop CNC mill - and I still get variances if I turn up the speed and if I haven't tuned/dialed in the backlash and stuff in awhile - that's just machine tolerance - never mind trying to keep accuracy drilling with tiny bits.  That's basically a long way of saying doing things by hand even with jigs/fixtures will always have some tolerance - notably with wood which has a grain and with small diameter drill bits inevitably lead to some wandering and misalignment. 

What I'd recommend are (3) things to help with the holes...

1. Use a drill press and vice... holding something with you hand will never give you great repeatability.  Assuming your drilling more than one bait at a time and they are the same thickness... you set your vice up and drill all the holes on a number of baits - this will minimize variance between baits to some degree provided you setup fixtures/stops to insure each bait is placed into the vice the same each time.

2. Use a center drill to start the hole.  You'll need to use a drill press or make your jig able to swap in different dia. bits.  Center drills are WAY more rigid than a .02-.04 diameter drill bit.... once you have a pilot hole from the center drill - you can then swap it out and go deeper with a standard drill bit as necessary and USUALLY keep things straight.

3. They sell small "X / Y" tables.... which basically allows you to "convert" your drill press into a makeshift mill with a vice.  The benefit here is once you line you table up parallel on the drill press - you can drill multiple holes in one axis all on the same center line fairly easy - for something like a jerkbait where you have multiple hook hangers.  On a crank might no be worth the effort

  One off amazon - not sure of quality/usability.

https://www.amazon.com/MultifunctionWorktable-Milling-Compound-Drilling-Adjustment/dp/B07DK8JJ16/ref=sr_1_3_sspa?dchild=1&keywords=xy+table&qid=1608046049&s=hi&sr=1-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExSTFWN0tHNEhXVlVIJmVuY3J5cHRlZElkPUEwMTc3OTYxMzNWT01HMUpSOEZGSSZlbmNyeXB0ZWRBZElkPUEwMDEyNTE0MUdMM0FGNjBRQjJZNCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

Work on jigs/fixture you can clamp down on tool like drill presses - that's only way you'll get repeatability/accuracy if that's your concern.

 

  J.

 

The jig was purposely done as a "hand tool".  Clamping a lure to drill one hole is even more time consuming than any other method I've seen/tried, so I ruled that out fairly early.

The jig shown above is being used with a drill press.

I looked up "center drill" because I was unfamiliar, and that wouldn't address the issue, either.  I'd end up just having two jigs then - one to center the center drill on the lure, and then one for the smaller drill bit - which would hide the pilot hole from the center jig anyway, so there wouldn't be much value - unless I got the mini mill table, and clamped each workpiece.  Again, time...  I'd be spending more time at the drill press than the bandsaw!

Once I addressed the issue with that jig as stated in a previous post, it's doing exactly what I wanted it to do.

However, you've given me some things to consider for future projects, or "one offs" where significantly more time would be invested.

You've also made me realize that I may have been a bit aggressive in my previous wording of what my goals actually are; that is to say that I don't need the lures to be 100% carbon-copy identical in every single physical aspect, dimension, measurement, and hole placement.  What my goal is is to have repeatable performance of the lures from example to example.  If that means that a variance of +/- .004" for the tow hook hanger, or +/-5g of weight, etc etc.

After all, as mentioned by several posted here, 100% repeatability by hand is largely a pipe dream.  So I'll settle for repeatable performance, if not identically repeatable production.

 

Hopefully this helps to clarify exactly how far down the rabbit hole I'm wanting to go. 

Edited December 15, 2020 by exx1976

[Vodkaman]

I too think that this has been a tremendous thread.

I think a performance repeatable swim action is not dependent on a fine tolerance. Some aspects are easy to control; hole positions, lip sizes, lip positions, ballast position. We can do our best with the carving and get fairly close, probably not to the same precision as the holes etc.

But if the body is a shade bigger or smaller than the standard set, and everything else kept the same, then the only thing that changes is the buoyancy. Copying a lure, which is what we are basically doing when trying to repeat our own design/build, is not just about XYZ. Buoyancy, the float sink status is also important. You cannot expect repeatability if the buoyancy is different.

The carving can wander out of tolerance, the wood density can vary, but most of the rest is controllable even in a hand build. BUT, by controlling the buoyancy, all those uncontrollables that mess with the tolerances of the lure can be brought back into specification by controlling the buoyancy, and surprisingly, this is a lot simpler than most builders think.

Tolerance is not just about XYZ, buoyancy can be controlled with equal or levels of tolerance, even with more precision regardless of the fact that the carving was out of tolerance and the wood density  was higher or lower than the original.

Controlling buoyancy does not mean that you need to wear a white coat in a science lab. It is just a few measurements that determine the ballast weight value to correct the buoyancy and the errant carving and wood density.

There are more scientific reasons why I drive the importance of buoyancy but I have never explained them. It is all to do with Center Of Flotation (COF), Center Of Gravity (COG) and Center Of Forces (COF) and the swim line position relative to the above. If the swim line is kept in the correct position relative to COF and the relation between COF and COG is kept under control, and all the XYZ bits are under control then the lure will swim the same.

I will post on the subject one day to explain, but I am still trying to get my head around it myself. When I know, you will know.

Dave

Dave