What's new
What's new

threading a block too heavy for the table

Just for kicks I drew up a "universal" large tap driver. The one I posted above was sized to fit a 1" holder and that is all well and good. But with a different approach a heavy duty holder could be made that would accommodate a variety of large taps.

The main difference from the first one is this holder has a larger (oversize) center hole. This one uses ten 3/8 or 5/16 set screws to align and fix the tap. It would take a few moments to by eye set up but getting the tap set axially and then driving the four fixing screw would not take much time. The pipe sockets shown would allow pieces of bar of whatever length to be inserted to provide enough leverage to make it easy to turn and the gussets provide strength. (And, yes, I am using this piece to practice my CAD drawing. So please forgive dredging up this stale thread.)

1701968646718.png

1701969024162.png
Denis
 
id use my Richmond radial arm drill......and have the job done in 10 minutes.....accurately.
How is that done? I assume you are working to scribed lines, right? Do you move the drill or the material to get it located? I've never seen radial arm drill work being done by someone who knows what he's doing, and all that weight with no leadscrews makes it look real challenging.
 
The head on a RAD moves freely both directions. Mine is a little one, only 6000#. The column rotates on bearings, and the head rolls on the arm.

If fussy i start with layout lines, spring loaded center punch the lines, then enlarge with a sharp center punch. Then I put the center punch in a drill chuck and, with the spindle running and the head unlocked, bring the point into the center punch mark. It will move the head to center. Lock and drill.


If not so fussy, I have a heavy center punch I use with a 3# hammer. It leaves a big enough mark to pick up with a 1 1/2 drill.
 
  • Like
Reactions: Mud
Here is the beast, 2” twist drill going into a lead sailboat keel. I had the thing under keel going vertical also. I designed a keel extension that bolted to the bottom of the existing keel. Weird project, glad I had the drill.
 

Attachments

  • IMG_0317.jpeg
    IMG_0317.jpeg
    850.6 KB · Views: 37
Mag drill with annular cutter is not the right tool for these holes, I am a little surprised so many people thought that a good idea. The steel is a solid block that is something like 16"x16"x18" and 1300 lbs IIRC without going back and seeing what the OP wrote. A big milwaukee mag drill with the jacobs chuck to use use twist drills would be a good choice as mentioned but those are not common.
Annular cutters are available in tap drill sizes if you look, hougen has them. (I dont recommend using them in a blind hole like this)
 
Absolutely. And not only because annular cutters are awful at chip evac, but wth is he going to do with the slug sticking up in the middle of the hole?
You take it over to radial drill and drill undersize of slug hole, then you die grind wall out, then you get to drill right size hole deeper because annuallers are not long enough. See- simple enough.

Almost any drill press can push a 7/8 twist with some pilot/step up holes.
 
thanks for the tips everyone! i got the job done. there was already holes there that I was enlarging to the 1-8. I cut a piece of all thread and put a center in it. Threaded that in the existing hole. Than machined a center that fit into the weld on on the the mag drill so I could center up on the center hole I put in the all thread that I threaded into the existing holes. I also was able to use the center I made for the mag drill to hold the tap straight and centered while I tapped the holes. It went pretty easily actually. I just used a regular 19" long tap handle. took some effort, but nothing horrible.
 
Mag drill with annular cutter is not the right tool for these holes, I am a little surprised so many people thought that a good idea. The steel is a solid block that is something like 16"x16"x18" and 1300 lbs IIRC without going back and seeing what the OP wrote. A big milwaukee mag drill with the jacobs chuck to use use twist drills would be a good choice as mentioned but those are not common.
Annular cutters are available in tap drill sizes if you look, hougen has them. (I dont recommend using them in a blind hole like this)
I'm curious why you say a annular cutter isnt the right tool? Thats what I used. The holes were 3/4". I was able to use a 7/8" annular and it worked great.
 
I'm curious why you say a annular cutter isnt the right tool? Thats what I used. The holes were 3/4". I was able to use a 7/8" annular and it worked great.
Annular cutter is always my first choice on most anything EXCEPT when it is a blind hole. Yes the little slug tower in the center of the hole can be removed but it is not worth the hassle of doing it compared to just using twist drills.

How did you remove the center slug?
 
The largest of the Greenfield tap and die sets come with (IIRC) the No 5 tap handle .......years ago my landlord gave me an empty Greenfield wood case with the big handle the only bit left ...........I immediately stopped using crescent wrenches to turn taps and reamers and used the handle ........big difference in thread quality and straightness
 
thanks for the tips everyone! i got the job done. there was already holes there that I was enlarging to the 1-8. I cut a piece of all thread and put a center in it. Threaded that in the existing hole. Than machined a center that fit into the weld on on the the mag drill so I could center up on the center hole I put in the all thread that I threaded into the existing holes. I also was able to use the center I made for the mag drill to hold the tap straight and centered while I tapped the holes. It went pretty easily actually. I just used a regular 19" long tap handle. took some effort, but nothing horrible.
This was a good way to do that job. But what you did was very different from what you said needed to be done in post #1....
Enlarging an existing hole is very different from drilling a hole....
If you had said - I need to open up some 3/4-10 holes to 1"-8, what would be the best way with my equipment (and list what you have)?
would have got you way different responses from the beginning.
Post #1:
how would you guys go about drilling and tapping some holes 1"-8 in a block of steel that is 16"x16"x18" tall? I have a typical bridge port style clone grizzly. I know I could turn the head and do the work next to the table, but wondering if anyone has done this and a good way to set it up without it moving on me.
 
Used to amuse me when someone took a big job to shop with zero proper /capable equiptment,got it half done ,and then would bring it to me 'too see if it can be got back on track'.........and I have seen rotobroach holes that didnt go through and left a pillar ......these are quite tricky to remove ,you need to make a hardened bushing to avoid a complete F/U .
 








 
Back
Top