Announcement

Collapse
No announcement yet.

Drill and Tap suggestions

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Drill and Tap suggestions

    I want to drill and tap a symmetrical pattern (like a grid) of 1/2" x 13 TPI holes in one of my 4'-0" x 4'-0" x 1/2" thick fab-tables. Using them for my mill hold down clamps. I've drilled and tapped before so that's not the issue in the slightest. I'm trying to figure out the best way to accomplish it. I was thinking of renting a magnetic drill press. Never used one and I haven't called to see what the rental price might be yet. Naturally I'd like to accomplish this without renting anythings. Just thought someone might have an idea. Never hurts to ask ya know.

    -SD:

  • #2
    If the fab tables are already built the mag base drill is likely the only practical way to do it.

    Comment


    • #3
      Originally posted by Illinoyance View Post
      If the fab tables are already built the mag base drill is likely the only practical way to do it.
      Thanks, the fab-table is already built. I only need to do one.

      Comment


      • #4
        Mag drill would be easier but you might get away with a small benchtop drill press if you swing the head away from the base. C clamp it down at the edge and then use the drilled and tapped holes as you go for hold down clamps.

        Comment


        • #5
          We bought a mag drill just to drill ~40 1" holes in 1" steel. Worth the investment (~$1500) to do the job. You find more uses for it.

          Layout the hole pattern and use a center finder to locate each hole carefully and you will be happy with the results.

          Mike

          Comment


          • #6
            For one table top just rent a mag drill. If equipped with a chuck you can tap with it also.

            Comment


            • #7
              Yes get a mag drill. I did part of my table with 1/2" holes. Only I didn't tap them. I just use a nut from underneath to hold the clamps.

              Comment


              • #8
                If you rent a mag drill,make sure it's reversible,not all of them are.

                Expanding on Ncjeeper's comment,you could drill the holes 17/32" for clearance and then tack weld on some 1/2-13 square nuts from the bottom for threads.That would save a lot of tapping.

                I use that method alot at work,McMaster carries the nuts,I use a flathead Allen capscrew to hold them for tacking.The 82* head holds the nut centered in the hole for alignment.One advantage is down the road,if a hread gets damaged or wears out,it's just a matter of knocking the old nut off and welding on a new one.

                https://www.mcmaster.com/90043a055

                Forgot to mention,the reason for using square nuts,is you can weld two opposite corners and not distort the threads.
                Last edited by wierdscience; 06-30-2019, 01:35 AM.
                I just need one more tool,just one!

                Comment


                • #9
                  Thanks guys, great idea on the nuts. Glad I asked.

                  Comment


                  • #10
                    Just dril,them to tap size then you can still use 3/8 or 7/16 bolts. Then tap them as you feel like it or its really needed. Meanwhile you have a functioning table.

                    Comment


                    • #11
                      If you tack weld all those nuts in place you will have domed plate for sure! A mag drill is the way to do this. If it doesn’t reverse and have speed control you still use it with a center to keep the tap straight.

                      Comment


                      • #12
                        Originally posted by wierdscience View Post
                        If you rent a mag drill,make sure it's reversible,not all of them are.

                        Expanding on Ncjeeper's comment,you could drill the holes 17/32" for clearance and then tack weld on some 1/2-13 square nuts from the bottom for threads.That would save a lot of tapping.

                        I use that method alot at work,McMaster carries the nuts,I use a flathead Allen capscrew to hold them for tacking.The 82* head holds the nut centered in the hole for alignment.One advantage is down the road,if a hread gets damaged or wears out,it's just a matter of knocking the old nut off and welding on a new one.

                        https://www.mcmaster.com/90043a055

                        Forgot to mention,the reason for using square nuts,is you can weld two opposite corners and not distort the threads.
                        That's a great idea for keeping bolt centered, I have a good selection of those 82 deg. Bolts Thanks!

                        Comment


                        • #13
                          Update, not that anyone is interested. They wanted nearly 100 bucks to rent a mag drill so I was doing some additional thinking today. Since my fab-table is already built I can't drill and tap except in place. I priced a 1/2x24"x24" plate today and it was 90 bucks. I'm thinking that will do for my jig plate setup as long as it's reasonably flat. (fingers crossed). I need flatness at least via eyeball and a straight edge on top of the plate. I haven't looked at them yet so I'll know tomorrow. That way I can drill and tap it on my Bridgeport, then place it on my fab-table.

                          -JW:

                          Comment


                          • #14
                            Is this the proper tap? I wanted to order a tap and drill today (27/64' in this case).

                            Comment


                            • #15
                              I use spiral points whenever possible, so good choice there, but the H limit on that tap is 11 - is that what you wanted?
                              Location: North Central Texas

                              Comment

                              Working...
                              X