question on drilling holes for folders

SVanderkolff

SVanderkolff

Joined
Oct 31, 2002
Messages
979
I am once again trying my hand at making folders and once again trying to eliminate the problems that I create. One issue I seem to have is an inability to drill a hole square to the material. Everything I drill goes through my surface grinder first so I know my piece is flat. What do you use to ensure that the drill bit is traveling dead square to the piece. I have a small drill press that I use all the time for just about all my drilling. It has almost no travel but unless I go through the process of squaring it up each time I move the work rest, I can't be sure it is staying square, and since I am either hand holding the piece or resting it on a 2/3/4 square a piece of scrap from a previous drilling can throw off the alignment. I do own a micro mill which I think would solve some of the base movement issues but not the set up issues. My micro mill also has a fair bit of travel when put under pressure. Do I need to pick up a second micro mill and use it just for drilling or are there drills out there specifically designed to be high precision?
A discussion on "How I make sure I am square." would be greatly appreciated.
Thanks
Steve
 
Steve, a micro-mill makes a good drill press, since they mostly have square columns and non-tilting tables.


Otherwise, remove the table from a small bench drill press, and use the base.. a 1-2-3 block is a good surface to drill on, since they're typically pretty accurate.


Not sure what type of folders you're making, but for really small holes, I've started using 140 deg notched point straight flute carbide drills exclusively, even for non-hardened material. If you buy quality, they eliminate the need to use a spotting drill first, they're designed to spot their own holes, and they're much more rigid, offering less flex than standard twist drills. That mitigates "walk" that causes slightly angled holes when drilling holes under 1/8". They also drill a significantly more concentric hole, that's not oversized in my experience.


I only make slipjoints, so YMMV, but they've eliminated the need to use a reamer after drilling, and leave tight tolerance holes for setup pins. The disadvantages of these drills is 1) cost, 2) straight flute geometry doesn't evacuate chips quickly so you need to use air if drilling anything thick.


I buy mine mostly off ebay, whatever USA manufacturers I can find cheapest at the time for the size I need. Typically just search for "straight flute carbide drill" and the size.



There are high precision drills. I've got a Hamilton Vari-Matic Precision sensitive drill (weighs about 300lbs), and a tiny servo motor precision drill designed for optical work, that i keep 1/16" drills in all the time. Use the bigger hamilton for the random stuff and larger sizes.


Good options used are Electro Mechano, Hamilton, Sigourney, etc. Ideally you need high speed for tiny drills. I'm pretty well versed in the various precision drills, so if you need help finding one, or want an opinion on one, feel free to PM or call.
 
I have used a small Jet drill press to make more than a couple thousand folders. I just squared up the table years ago and use a precession vise sitting on the table to rest the part on. I clamp nothing, just hand hold. Short screw machine cobalt drills help a lot also.
 
I'd be very interested to hear exactly what problems your current setup is causing, especially if someone like Hanson is using a similar setup with excellent results.
...and thanks for the tip about the carbide bits, Javand! Gotta try those...
 
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Square the bit to the drilling surface ( table or bed),......use only sharp bits,....drill slightly undersize,......ream to exact size,.... carbide is your friend.
 
One of my drill presses uses a taper pin (not installed by me) on the table pivot to indicate level. It wouldn't take too much to add a taper pin to your table to ensure a return to position.
 
Short, sharp drill bits and very little downward force. Check the square of table and bit after every change in table height, angle, etc.
 
Tram your table. My Craftsman 12" benchtop drill presses had a pin installed that was supposed to hold the table square to the spindle. Unfortunately, their idea of square was different than mine. I removed the pins so the tables could be adjusted and then trammed them in with a DTI. I have not found a need to re-tram after changing the height of my tables; the columns appear to be fairly straight. Good drills and technique will also help.

Bob
 
Open the top cover of the drill press, lower it, and as Javand suggested, use the lower table.
Just check if the lower table is square!!!!
I use the movable table, backed up by a bottle jack....keep the travel long and adjust with 123 block, but if i need to touch the table it becomes necessary to reassure the table is square....no other way.
A pain in the ass, i agree, but it's worth, trust me.
Even if you don't have reamers, drilling undersize and step up to the final drill makes wonder....try different drill brands and find the ones that better match your pins.
 
I squared the table on my little Jet over 18 years ago and have never had to do it again. Table is moved up & down everyday. Ya'll either have some messed up machines, or are over thinking this stuff? :D
 
Thanks to All
I like the idea of lowering the body of the drill and using the bottom table as the platform. I also have to wonder if I am placing the blame of a not centered blade on hole alignment when it should be something else. I had simply assumed that since everyone kept talking about the holes needing ot be exactly square to the piece that that wsa where the problem was. I will need to do more figuring.
Thanks Again
Steve
 
I drill my folder holes by hand with a flexible shaft machine.
 
Steve.
There is a simple way of checking that the table is sitting correctly. Take a say 3/32 rod, old style coat hangers worked real well for this, about 12" long and make a "Z" with it. Now make it a little longer by pulling on each leg. Place one leg in the drill chuck and the other to just touch the table just as wide as you can without it going off. Now turn the chuck by hand. Does the wire stay touching? on one of mine I overlaid a new
base with shims to get it level. I hope this helps.
Frank
 
Don Hanson III said:
I squared the table on my little Jet over 18 years ago and have never had to do it again. Table is moved up & down everyday. Ya'll either have some messed up machines, or are over thinking this stuff? :D
Click to expand...

Both ;)
Actually absolute precision is not required, and if the pin seems square from different views in relation to the liner/bolster, generally the knife will work perfectly.
Also perfectly round holes are not mandatory, unless the pin is wobbling remarkedly.
But that doesn't mean we shouldn't overlook the drill press tramming...with some machines the table is not much solid and it is better to check every now and then
 
Drilling is a roughing operation to remove material from a hole, but not to make an accurate hole. Not many people are following a drilled hole with a single point bore these days, but that will get it round and square prior to reaming.

For most needs, an accurate hole is spotted, drilled and reamed. You can use a "preream" endmill to chase a drilled hole prior to reaming to get it square and in position, similar to boring.

If you're just drilling and not reaming, your hole is not round or dimensionally accurate and, IMO, isn't good for EDIT: holes that need to be accurate, such as pivot holes.

...my .02...
 
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Btw, in topic...

Somebody used Drill Press FLOTT TB 13 PLUS ?
I thinking about this drill mostly for folder work.
And Polish WS-15 104kg , max drills 16mm, for hard drilling ;)
 
Flott makes excellent drill presses, you can't go wrong with any machine they make. I have one of their big ones that I couldn't live without.
 
Nathan, you are right on principle!
And it does surely apply when it boils down to match those tang/scales interfaces of yours :)
It is also true that for making folders by hands with pinned pins more amplitude of tolerances are allowed. Nevertheless trying our best to have the holes straight and reamed it's not wasted time. Even without fancy tramming jigs it is possible to get our drill presses pretty much square and make a better job.

My bottom line is: be aware of the problem, but don't be discouraged, even with small equipment and a bit knowledge it is possible to make a good job.
Best is to get:
- center punch
- undersized drills
- reamer
....and tramming your press the best you can...also try to make up against flex, have some support underneat the table, because using low pressure feed could be worst.
 
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I ream the pivot holes, not the others. If the bit is 90 degs to the work & good sharp bits are used there should be no issues.
 
yep on pivots 3 things count
size
better be round
and perpendicular to the piece

that is if you want the action to be smooth and true
 
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