Need Jig Design Advice - 3D Drawing Pictures Attached

I'm in need of a jig for drilling holes in aluminum. Currently trying to design it myself, and would like to get advice/suggestions/recommendations from anyone with experience and willing to help.

JIG USAGE:
-Jig will be used to drill 6, .5" diameter holes through a 2" x 5" x .125" thick piece of extruded 6061 aluminum. Intend to drill from the top face (5" plane) through the bottom face to create 2 holes for each drill operation.

TOLERANCE:
-The material hole location tolerance does not have to be tight at all. The finished product holes will receive a .375" diameter bolt, so lots of room to play.


USAGE FREQUENCY:
-Jig will be used very lightly. A rough estimate would probably be used to make 1 or 2 parts per month, most likely less. Will be an as needed basis, and not needed often.

CONCERNS:
1. -Would like to use this jig in an unconventional manner. I.E., I would like to drill the holes without the use of a drill press or mill. Would like to use a cordless drill. Initially I tried to find a threaded .5" drill, with the intention of using a .75" drill bushing to guide a rod that the drill is threaded into, but I can't find a threaded drill in .5".

Because of this, my drill will make contact with the ID of the bushing and most likely wear the bushing prematurely. I'm considering using a spotting drill, since the material is only .125" thick. I'm also curious if the wear would be so minimal considering the frequency of use that it's a non-issue in this case.



2. -Do I need to clamp the jig down to the part, considering I'm incorporating a threaded locating pin to press the material up against 2 fixed locating pins on the opposite side of the jig?


3.- Are there any shortcomings within my design up to this point that I'm not aware of? (this is my first jig design/build attempt).



Thanks for any help.

Casey


Click thumbnail for full size image:

For super low volume hand held drill jigs ... we use plastic or aluminumum or mild steel with no drill bushings. Just hold your hand held drill square and don't smash into the jig as you go through. It will last a long time at 1 or 2 uses per month. And with 1/8" clearance on your bolt, it's still gonna fit for a long time after it is "worn out".

I am just making a new drill fixture for one of our parts. We drill three radial 1/8" holes in a PVC plumbing cap. Fixture was made from a block of gray PVC plastic. IE about the softest material in the world. It was used to make about 400 parts before it became worn enough the operator complained. So your steel drill bushings in an aluminum chassis will work fine for what you want.

Edit: I forgot I have an Imgur account. Placed thumbnails in in OP.

kb0thn said:

For super low volume hand held drill jigs ... we use plastic or aluminumum or mild steel with no drill bushings. Just hold your hand held drill square and don't smash into the jig as you go through. It will last a long time at 1 or 2 uses per month. And with 1/8" clearance on your bolt, it's still gonna fit for a long time after it is "worn out".

I am just making a new drill fixture for one of our parts. We drill three radial 1/8" holes in a PVC plumbing cap. Fixture was made from a block of gray PVC plastic. IE about the softest material in the world. It was used to make about 400 parts before it became worn enough the operator complained. So your steel drill bushings in an aluminum chassis will work fine for what you want.

Click to expand...

Thanks! Very much appreciated. However, now I really feel like I spent way too much time designing my overkill jig lol....

Make it from 1 piece of plate (no side plates needed)

Dowel pins (4) hang down along 2 edges, no drill bushings needed.

lay plate on top, push up against 2 edges that have the dowels, external clamp
to hold.

Xfer punch hole locations.

Remove jig, drill to suit.

digger doug said:

Make it from 1 piece of plate (no side plates needed)

Dowel pins (4) hang down along 2 edges, no drill bushings needed.

lay plate on top, push up against 2 edges that have the dowels, external clamp
to hold.

Xfer punch hole locations.

Remove jig, drill to suit.

Click to expand...

Thanks for the advice. Much appreciated. The only thing is (I didn't mention this in my OP) the holes on one side of the part will be .084" closer to the locating edge than the other side of the part. The reason for this is that there's a second part that slip fits inside of the part being discussed that has an OD that's .287" less than the ID of the part being discussed. The reason for this is ease of installation of all parts in the field, if it can't be done on the bench. It's hard to explain. I'd probably have to create a drawing to explain it if I'm not making any sense.

Anyhow, that was my reasoning for wanting to drill holes through both sides of the part in one operation. The way the hole location is laid out you can't rotate the jig 180 degrees as the holes on the other side of the part wouldn't be correct. I guess I could install the pins in such a way that they protrude out of both sides of the part. That would allow me to locate with either face of the jig by flipping 180 degrees, but then that introduces another potential source for error and a possible ruin part.

I should have mentioned the holes being offset in my original post. Sorry about that.

Make qty (2) jigs, spray paint all over different colors.

This style of fixture design is so cheap to build, you could use laser cut 1/4" plate.
Or simply layout on a bridgeport.

digger doug said:

Make qty (2) jigs, spray paint all over different colors.

This style of fixture design is so cheap to build, you could use laser cut 1/4" plate.
Or simply layout on a bridgeport.

Click to expand...

I always think of the most complicated solution first lol... Thanks! BTW, here are pictures of the finished parts just in case anyone'r curious.

One leetle mistake I made....only need qty (3) pins.

2 to align along the long edge of the tubing, and one
more for the end stop (hits the cut edge).

digger doug said:

One leetle mistake I made....only need qty (3) pins.

2 to align along the long edge of the tubing, and one
more for the end stop (hits the cut edge).

Click to expand...

You're the man!

If you're at all concerned about wearing out the hole locating bushings you could simply purchase readily available hardened drill bushings. They don't wear out quickly as they're made for production use of greater frequency than what you're contemplating and help to keep the drill perpendicular on the intended location. Locating the part by edge stops/dowels and locking it in position with some sort of thumb/palm screw is good if location from edges is important. If that's unimportant and just the hole pattern is the concern then external clamps can be fine. Always consider the person that will be using what you're designing. You may understand what's important but do they? Try to make things foolproof and simplicity is best. Two jigs painted different colors may be the right idea.

AD Design said:

If you're at all concerned about wearing out the hole locating bushings you could simply purchase readily available hardened drill bushings. They don't wear out quickly as they're made for production use of greater frequency than what you're contemplating and help to keep the drill perpendicular on the intended location. Locating the part by edge stops/dowels and locking it in position with some sort of thumb/palm screw is good if location from edges is important. If that's unimportant and just the hole pattern is the concern then external clamps can be fine. Always consider the person that will be using what you're designing. You may understand what's important but do they? Try to make things foolproof and simplicity is best. Two jigs painted different colors may be the right idea.

Click to expand...

I think I'd prefer to go with one jig vs having multiple jigs. I know multiple jigs would work fine,and be easier and cheaper to create but I don't mind going the extra steps to create a single jig that simplifies its use. I'll go with drill bushings as initially planned, and use hardened bushings as you suggested. I do need the holes to be located, not just the pattern, so since clamps would not suffice in combination with locator pins/dowels, do I need to create a side to thread thumb screw through that runs the complete length of the jig, or could I get by with a side that's say 4" long and screwed to the side of the top plate? See attached updated 3d picture of top plate.

Thanks

No drill bushing needed, if the base plate is steel (even mild steel, just
not aluminum) you use a transfer punch to mark the locations.

Loads are very low, usage is very light.

ccater1 said:

I think I'd prefer to go with one jig vs having multiple jigs. I know multiple jigs would work fine,and be easier and cheaper to create but I don't mind going the extra steps to create a single jig that simplifies its use. I'll go with drill bushings as initially planned, and use hardened bushings as you suggested. I do need the holes to be located, not just the pattern, so since clamps would not suffice in combination with locator pins/dowels, do I need to create a side to thread thumb screw through that runs the complete length of the jig, or could I get by with a side that's say 4" long and screwed to the side of the top plate? See attached updated 3d picture of top plate.

Thanks

Click to expand...

I'm not sure I understand the purpose of the ball-tip posts, if that's what they are. If you have the jig plate directly down on the surface of the work piece, assuming they are both reasonably flat, your locations will be more accurate. If I were making that and using the jig to make the tube parts shown, I would simply clamp the top jig plate to the top wall of the rectangular tube using small C-clamps or machinist's parallel clamps after locating the part against the pins. Drill bushings aren't a bad idea, but if you are hand drilling with a 1/2" drill, better get well lined up, or you could get cockeyed in a hurry.

specfab said:

I'm not sure I understand the purpose of the ball-tip posts, if that's what they are. If you have the jig plate directly down on the surface of the work piece, assuming they are both reasonably flat, your locations will be more accurate. If I were making that and using the jig to make the tube parts shown, I would simply clamp the top jig plate to the top wall of the rectangular tube using small C-clamps or machinist's parallel clamps after locating the part against the pins. Drill bushings aren't a bad idea, but if you are hand drilling with a 1/2" drill, better get well lined up, or you could get cockeyed in a hurry.

Click to expand...

Thanks for your reply. The ball tip posts are round head locating pins. My thinking behind installing them on the bottom of the jig plate is to provide clearance between the part and the jig for chips to clear. The pins provide .5" clearance. If they're not needed for chip clearing I will omit from the design. I was really hoping the drill bushings would be tight enough that they would align my drill to the part while hand drilling. It seems I'm mistaken if you're saying the drill could get cockeyed inside the bushing. The bushings in the above model are 1" long.

digger doug said:

No drill bushing needed, if the base plate is steel (even mild steel, just
not aluminum) you use a transfer punch to mark the locations.

Loads are very low, usage is very light.

Click to expand...

I'm not confident that my hand drilling skills are up to par for drilling accurate holes by transfer mark only lol... I'm worried the drill will walk on me

ccater1 said:

I'm not confident that my hand drilling skills are up to par for drilling accurate holes by transfer mark only lol... I'm worried the drill will walk on me

Click to expand...

I have to ass-u-me that here on "practical Machinist" you would be employing
a simple, guided drill.

Commonly known as a "Drill press".

Even a $50 HF benchtop model will doo here.

ccater1 said:

I'm in need of a jig for drilling holes in aluminum. Currently trying to design it myself, and would like to get advice/suggestions/recommendations from anyone with experience and willing to help.

JIG USAGE:
-Jig will be used to drill 6, .5" diameter holes through a 2" x 5" x .125" thick piece of extruded 6061 aluminum. Intend to drill from the top face (5" plane) through the bottom face to create 2 holes for each drill operation.

TOLERANCE:
-The material hole location tolerance does not have to be tight at all. The finished product holes will receive a .375" diameter bolt, so lots of room to play.


USAGE FREQUENCY:
-Jig will be used very lightly. A rough estimate would probably be used to make 1 or 2 parts per month, most likely less. Will be an as needed basis, and not needed often.

CONCERNS:
1. -Would like to use this jig in an unconventional manner. I.E., I would like to drill the holes without the use of a drill press or mill. Would like to use a cordless drill. Initially I tried to find a threaded .5" drill, with the intention of using a .75" drill bushing to guide a rod that the drill is threaded into, but I can't find a threaded drill in .5".

Because of this, my drill will make contact with the ID of the bushing and most likely wear the bushing prematurely. I'm considering using a spotting drill, since the material is only .125" thick. I'm also curious if the wear would be so minimal considering the frequency of use that it's a non-issue in this case.



2. -Do I need to clamp the jig down to the part, considering I'm incorporating a threaded locating pin to press the material up against 2 fixed locating pins on the opposite side of the jig?


3.- Are there any shortcomings within my design up to this point that I'm not aware of? (this is my first jig design/build attempt).



Thanks for any help.

Casey

Click to expand...

This was noted in the original post.

digger doug said:

I have to ass-u-me that here on "practical Machinist" you would be employing
a simple, guided drill.

Commonly known as a "Drill press".

Even a $50 HF benchtop model will doo here.

Click to expand...

I guess that's what happens when we ass-u-me lol... To expound a bit on the why I'd like to hand drill: The finished part will range in length from 16' to 24' long. That's not a typo. 16 to 24 feet, not inches. I'm not setup to place material that long in my drill press or milling machine. So my preference is to hand drill these parts if possible. I guess I could employ a portable/magnetic drill press and clamp it down, but I don't have one, so I'd have to purchase one.

ccater1 said:

Thanks for your reply. The ball tip posts are round head locating pins. My thinking behind installing them on the bottom of the jig plate is to provide clearance between the part and the jig for chips to clear. The pins provide .5" clearance. If they're not needed for chip clearing I will omit from the design. I was really hoping the drill bushings would be tight enough that they would align my drill to the part while hand drilling. It seems I'm mistaken if you're saying the drill could get cockeyed inside the bushing. The bushings in the above model are 1" long.

Click to expand...

If the bushings are 1" tall, that will likely be enough to get the drill lined up well. Regarding the chip clearance space, I think it to be unnecessary, based on the planned usage and materials involved. I would be more concerned about making sure the jig stays in place during drilling, and that the entire setup is stable enough to efficiently drill by hand. If I were forced into doing this work in the way you envision, I would want to be able to clamp the jig/workpiece to something for stability, or hold it all in a vise. I think it would be a mistake to think you can hold the jig and workpiece with one hand and drill with (only) the other hand. As noted above, a Harbor Freight cheapie drill press would actually do this job in an "OK" manner.