Drilling/Tapping Long Part

[Jester966]

Scribe, center punch, then use your drill press to spot and drill. +/- .010" should be achievable if you're careful.

 

[NC Rick]

Sorry if I am being dumb but it is a drilled hole so it won't be fantastically accurate anyhow (unless you were going to bore it). If you lay it out accuratel, Center punch with care, use a spot drill and tram the part in the drill press, would that be accurate enough?
oops! Kinda 205'd by @Jester966 ! I actually have a 996 ducati (no Porche sadly) and I do not Jest. Sorry, I'm weird.

 

[devils4ever]

Yes, I think I'll give the drill press a try. Thanks all.

 

[nnam]

How deep is the tap? Is the metal stick round, smooth or even? Those can help in alignment vertically in a drill press. If you have an XY cross slide, it further helps the centering with an indicator.

 

[devils4ever]

I need to tap 1" in with a drill depth of 1.25". The metal bar is cold rolled steel.

 

[NC Rick]

I need to tap 1" in with a drill depth of 1.25". The metal bar is cold rolled steel.

That's a challenge to do within a few thousandths. The drill in that size as well as the tap take a lot of torque and pressure so tapping and drilling to those tolerances will take a very stout drill press I don't think the mini-mill will be so good either. Someone with a pretty good size lathe is the ticket. preferably where your part will pass through the tail-stock. A drill press like my 16" delta floor model would be like a wet noodle for that.

 

[tq60]

I have a lathe, but it's a mini-lathe and wouldn't be long enough.

Easy!

Start with a a pipe female end cap that is one size too small to go on to your work or a solid round that is an inch or so long.

Face one end then flip and face opposite.

Center drill then drill through hole 1/8 inch.

Consider making 2...

Now bore out inside to same diameter as your work but leave 3/8 or so in the bottom.

Being turned in lathe and all critical work bone in one operation the pilot hole will be exact center.

This slips onto end of work and guides the drill exactly in center.

A second one with tap drill can increase final accuracy.

Place work vertically in drill press through the hole usually in center of table.

You can drill hole in 2x4 same as work to support in dp.

Measure from column to insure vertical and also check with level.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[devils4ever]

tq60: Very interesting idea! I like your methodology.

My part is not square, but rectangular. I think this method will still work for a rectangular profile, correct?

You (correctly) assumed that I wanted the hole centered on the end! I guess this method only works for a centered hole?

A question on drilling this on the drill press. Does the part go below the table or above? The part is bigger than the hole in my DP table.

 

[Alcap]

Just a thought , could you put the drill in the lathe headstock , use a angle block to hold the bar on the cross slide and feed the saddle into the drill ?

 

[devils4ever]

Possibly, but my lathe is pretty small and the cross slide isn't that big. The part would only be held at one point and might want to pivot.