Drilling multiple holes in a line.

[HCJtractor]

I’m building a landscape rake and need to drill 50 3/8” holes spaced two inches apart along a straight line. I plan to use either 1/2” or 3/8” angle or something similar. I have a floor drill press, but it’s not a great one, but adequate. I’ve even thought about buying a mag drill if I thought it would help. Saw a off brand online for $450 that got good reviews.

How would you guys do this? Using a starter punch seems inaccurate. I thought about building a jig with an indexing pin, or a template. Any ideas on how to set this up? And what bit would be best, or even an angular cutter on a mag drill.

I want them to be accurate so the tines will look even and straight.

I thought about clamping a fence on my welding table, having in feed and out feed roller supports, adding a 3/8” stud to my table in the two inch from bit position as an index, then just work my way down, moving the steel one increment at a time. Seems this would work with a mag drill. Would be harder on my drill press since the table is so small and sometimes rotates with a off set load.

The angle will be 84” long and depending on what I can find at the scrap yard, could weigh up to 100 pounds. I want it stout.

Thanks for any advice!

 

[mrmikey]

Make a nice clean scribe line along the length whatever distance in from the heel you decide, using a try square as a gauge. Measure off the running distance, if 2" centers, mark it off running so the error doesn't add up. i.e., 2", 4" 6" etc, Scribe the lines, center punch with a sharp punch and predrill a small hole, 1/8" or so with a hand drill and go from there with a 3/8" drill in a hand drill. Unless you have another use for a mag drill, it seems like a big expense.......M

 

[/pine]

If I was doing it myself...I would make up temporary supports etc. and extend the table on my existing drill press to accommodate a long fence...then just mark out the 2" spacing and drill away...

Another option is taking the angle to a welding/fabricating shop and have them punch the holes...

 

[oosik]

Well - in my situation I would have little choice. Measure and mark out all the spots for drilling. Chuck up a small drill bit - 1/4" - in my drill press and go down the line drilling smaller starter holes. Chuck up the size you want for final hole size and go back down the line.

I would clamp down a backing plate on the drill press table - that way the angle iron can only move - left/right - not forward/back also.

 

[KennyG]

I wouldn't drill them. I would use a large angle or box member and weld to the face of it.

 

[Big Barn]

A mag drill won’t work “per se”. Not enough mass for the magnet to work without a bigger base and jig.

Steve (BuckitCase) will hopefully chime in if you decide on this route. He has the mag drill/multiple hole via jig all figured out.

Since you already have a drill press consider what others have mentioned for layout and buy an annular sheet metal cutter for your press.




The best way would be to punch the holes on an iron worker. Since I got mine earlier this year I only use my drill presses less than half the time.

 

[Industrial Toys]

I made a small rake for my Steiner but bolted each S tine to a bushing and mounted them on a shaft, so they can float or be arrested.

I would make a template with maybe ten accurate smaller holes, say 1/8, clamp it progressively along and just make a dimple, then use a pilot and the larger drill.

It is hard to get a center punch on target, but I find the iron worker to be a lost cause for accuracy, unless you prepunch the holes anyway..

We used to use a bluing ink for layout work, but I just color the metal with a sharpie, so the scribing shows up nicely and rub it off with some acetone.

I would love to find an automatic center punch that isn't so thick, you can't see the point.

 

[sdquick]

I would buy some peg board (1" hole spacing) to use as a template. Cut a piece and silicone it and clamp it to the steel and then drill a pilot hole in every other hole (1/8" or 3/16" depending on the peg board). Go back with the larger bit.

 

[Big Barn]

We used to use a bluing ink for layout work, but I just color the metal with a sharpie, so the scribing shows up nicely and rub it off with some acetone.

I would love to find an automatic center punch that isn't so thick, you can't see the point.

I use blueing ink also.


And you’re right about center punch accuracy. If I’m REALLY particular I’ll use my optic punch for layout. Sometimes I tap lightly with a prick punch followed by a regular center punch. MOST times I’m just too lazy and use the auto center punch

Below left to right in order of preference (quick and dirty to OCD)

 

[metalbender]

When I did the holes for the grader blades on my land plane, I made a quick jig to cut the holes with the plasma cutter. Needed 5/8 holes in 3x3x3/8 angle. Stuff is pretty heavy to set up in the drill press or mill. Saved hrs of drilling.