Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 25

Thread: Drill and Tap suggestions

  1. #11
    Join Date
    Mar 2013
    Posts
    1,644

    Default

    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.

  2. #12
    Join Date
    Jan 2014
    Location
    Edmonton Alberta
    Posts
    1,592

    Default

    Quote 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!

  3. #13
    Join Date
    Mar 2003
    Location
    Arizona
    Posts
    1,122

    Default

    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:

  4. #14
    Join Date
    Mar 2003
    Location
    Arizona
    Posts
    1,122

    Default

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


  5. #15
    Join Date
    Jun 2001
    Location
    North Central Texas
    Posts
    2,564

    Default

    I use spiral points whenever possible, so good choice there, but the H limit on that tap is 11 - is that what you wanted?

  6. #16
    Join Date
    Oct 2012
    Location
    San Antonio TX, USA
    Posts
    2,777

    Default

    not an expert, but the thread pitch limit on that tap (H11) looks pretty loose. H3 is the standard run of the mill pitch limit. The one you linked to might be for holes that will later be plated. Other than that, that style will work a treat.

    edit: Joel, you fast!

  7. #17
    Join Date
    Mar 2003
    Location
    Arizona
    Posts
    1,122

    Default

    I should have been clearer. I'm going to use my Bridgeport to drill the holes in 1/2" plate for my 1/2'" x 13 TPI Bridgeport clamp bolts. I'll be tapping by hand (as needed in the plate) using one of those cedarberg hand tappers (assuming the tap will fit in the holder). I have a large and small hand tapper. The also had a H3 listed, I haven't a clue the difference, that's why I'm asking.

  8. #18
    Join Date
    Oct 2002
    Location
    Kirkland, Washington
    Posts
    2,179

    Default

    Quote Originally Posted by MikeL46 View Post
    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
    Common practice on mag drills is to lay out your holes and centerpunch them. For each hole, install a tapered pin in the spindle. Lower the pin with the magnet off, feeling for the hole. When you feel the pin catch the centerpunched hole, turn on the magnet, install your bit and drill. No need for a center finder.

    If $100 is too much for the use of a mag drill, carefully buy a mag drill (used), use it, and resell it. If you are careful about pricing, you can often achieve "free rent" this way.

    metalmagpie
    Last edited by metalmagpie; 07-05-2019 at 05:06 PM.

  9. #19
    Join Date
    Apr 2012
    Location
    Sydney
    Posts
    759

    Default

    Get a spiral tap and put it in the drill chuck or a collet on your Bridgeport mill. Run it thru at 75RPM. It will go ok.

    I just drilled and tapped 60+ 12mm holes in a 13mm plate; so very similar. I do have a tapping chuck but it did NOT need to be reversed; essentially I set the clutch to go straight thru. The tap used was NOT a spiral type. I gave it a brush after each hole and added a drop of lubricant (tap magic) for each hole.

    If a spiral tap was used either in drill chuck or a collet I am very confident you will have no problems. Just allow the tap to go thru; stop the machine; put it in reverse and back it out.

    Be sure NOT to put too much pressure on the lever lowering the quill when tapping; just enough pressure to get it to bite then very lightly follow the tap thru. If you apply too much pressure it will sort of ream the hole and make a less than sharp thread.

    I mounted my 13mm plate on a few 30mm x 30mm wooden blocks to give clearance. This was enough to allow the tap to go full depth.

    As to the tap type. Go for the "middle one", the intermediate. There is not need for the taper tap. The intermediate will start just fine.


  10. #20
    Join Date
    Jul 2017
    Location
    Springfield Mo
    Posts
    607

    Default

    Quote Originally Posted by Smokedaddy View Post
    Is this the proper tap? I wanted to order a tap and drill today (27/64' in this case).

    Rather have a spiral flute tap personally. Not that the spiral points dont do an excellent job at pushing the chips out of the hole, but i prefer pulling them out, means i can use the same tap on non-thru holes if needed

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •