I need a setup to drill and tap 5/8-11 holes in cast iron. Don't have room on the floor need something that I can use on a bench. How to find a drill press that will work for me? Or any other setup? I was thinking drill press to drill the hole and hand tapping machine to tap it. Will not be used for anything else. Just this specific operation.
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Setup to drill and tap 5/8 hole
- Thread starter Pysiek
- Start date
- Replies 41
- Views 5,343
MichaelP
Titanium
- Joined
- Dec 7, 2008
- Location
- IL/WI border
How many holes/how often? That're the thickness of the metal and the overall size of the parts?
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
Getting the holes straight is important so you can find/follow the hole with the tap. Using a drill press you can put a center in the chuck and use that to make your tap run straight. Cast iron chips are a bugger, like balls or chunks of cast iron so good to blow them out or clear them out. We/I used to tap CI dry, but nowadays many are suggesting soapy water or tap flid (?).
I think a slower drill speed is good so a 1/2" drill motor or 500 or less RPM drill press speed may be good.
Good to find a good process to locate your holes, perhaps C Clamp a mating part if there is one and punch or spot drill the locations.
To make your tap drill size better you might pre-drill with a smaller drill then use your tap drill.
With not having a drill press, you might find a friend who has a drill press and make a steel flat bar to drill a tap drill size hole and a tap size hole so to be clamped to your job as a straight making gauge/fixture.
In a pinch, one can use a machinist square or a good square block/something to look at/over to eyeball see that you are freehand drilling/tapping straight. It is very easy to hand drill holes Way Off the correct angle.
I think a slower drill speed is good so a 1/2" drill motor or 500 or less RPM drill press speed may be good.
Good to find a good process to locate your holes, perhaps C Clamp a mating part if there is one and punch or spot drill the locations.
To make your tap drill size better you might pre-drill with a smaller drill then use your tap drill.
With not having a drill press, you might find a friend who has a drill press and make a steel flat bar to drill a tap drill size hole and a tap size hole so to be clamped to your job as a straight making gauge/fixture.
In a pinch, one can use a machinist square or a good square block/something to look at/over to eyeball see that you are freehand drilling/tapping straight. It is very easy to hand drill holes Way Off the correct angle.
idacal
Hot Rolled
- Joined
- Aug 9, 2011
- Location
- new plymouth id
1 hole a week? Just use a hand held drill for the hole. and a good tap in an impact wrench
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
"One hole maybe once a week."..then a drill press is due. You might drill and tap from the backside so setting on a flat to the DP table, and better suited to tap the shoulder interference area.. The drill hole will be straight..putting the tap in the chuck so the tao will also be straight.
If you find you need to clear the shoulder you might buy a piloted step tool so the nose will fit the 5/16 bore and be end-cutting to a diameter good to clear the 5/8 tap.
CI drills easy but still you should get a 1Hp (8 amp) or larger DP and a 1/2" or larger drill chuck (IMHO)
Good to have a "no spin-out device" on a drill press table.
My choice would be a used tall DP, likely find one for 100/200 or so..and you can always sell it for what you pay..and it will last for many years.
For such work a bench DP should be bolted to the bench
NC Rick
Aluminum
- Joined
- Oct 7, 2007
- Location
- Asheville, NC
Cast iron is so easy to drill and tap but I think it is critical to guide the tap in a straight hole. The through hole you have helps. I have done all that with no lubricant. It is easy to make the tap track off the line of the hole when hand taping. I’d start the tap in a drill press and use a spring loaded center type tap guide in the drill press to help me hand tap the full depth.
Most of my experience is using a mag drill and for that size, I use a spot drill followed by the tap sized drill to make the hole. No predrill.
Most of my experience is using a mag drill and for that size, I use a spot drill followed by the tap sized drill to make the hole. No predrill.
Let me say I used to do it in a manual lathe. It was pretty hard to tap with hand device and I used little bit oversized drill so to remove less material. There was no chips produced just powder. Do you guys think this device might work for tapping?
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
A good drill press can drill and tap..it is much the same as a tapper but you need only buy one machine/device.
One can put a small tap in a DP chuck, or use the DP spindle to tail center a tap wrench.
This is what I'm trying to find. Which drill press will be powerful enough to perform the task.
dgfoster
Diamond
- Joined
- Jun 14, 2008
- Location
- Bellingham, WA
One a week——NC Rick in post 7 suggested the way I’d go. I would simply use the spring center in any DP and a vintage tap holder. Trying to get a DP with low enough gearing to do this comfortably seems like way overkill for one a week. Just locate the part on the table using a drill that fits the existing hole—sloppy method but good enough for this. Clamp it down. Drill need hole to size. Put in the center and tap it. Done.
Denis
Denis
MichaelP
Titanium
- Joined
- Dec 7, 2008
- Location
- IL/WI border
Why not continue doing it on your lathe? Chuck the hub of the wheel, drill the hole, use a tap in a larger tap holder with a low spindle speed. Done.
Some details in case you did it differently... Use a center in the tailstock to keep the tap holder aligned well (some tap holders have center holes in the back, some may need a simple sleeve/adapter). Unlock the tailstock and move it by hand toward the chuck while the hole is being tapped. One of the tap holder handles will rest against the cross slide and slide along it (do not hold it by hand).
Some details in case you did it differently... Use a center in the tailstock to keep the tap holder aligned well (some tap holders have center holes in the back, some may need a simple sleeve/adapter). Unlock the tailstock and move it by hand toward the chuck while the hole is being tapped. One of the tap holder handles will rest against the cross slide and slide along it (do not hold it by hand).
I don't have that lathe anymore.
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
RE: (some tap holders have center holes in the back, some may need a simple sleeve..
Many taps also have a tail end center so that center can be used on a lathe or drill press to hold the tap and a tap wrench used to turn the tap.
Most 1 hp DP can turn a 5/8 tap drill, but not turn a 5/8 tap ..you likely need to turn the tap by hand as it may/will slip in a drill chuck.
Be sure the drill chuck is big enough to hold a 5/8 tap drill.
You may need to pre-drill a smaller hole/may need a hex shank drill so it does not turn in the drill chuck.
The part will try to spin so need to have a holding device for drilling and tapping.
Many taps also have a tail end center so that center can be used on a lathe or drill press to hold the tap and a tap wrench used to turn the tap.
Most 1 hp DP can turn a 5/8 tap drill, but not turn a 5/8 tap ..you likely need to turn the tap by hand as it may/will slip in a drill chuck.
Be sure the drill chuck is big enough to hold a 5/8 tap drill.
You may need to pre-drill a smaller hole/may need a hex shank drill so it does not turn in the drill chuck.
The part will try to spin so need to have a holding device for drilling and tapping.
Scottl
Diamond
- Joined
- Nov 3, 2013
- Location
- Eastern Massachusetts, USA
Don't know your budget but how about buy a solid benchtop drill press and add a speed reduction kit like one of these?
Drill Press Reduction Kit, lower RPM, more torque! - Rogue Fabrication
Probably the easiest setup for tapping is either your hand tapper or pull the plug on the DP and rig up a hand crank to the spindle.
Drill Press Reduction Kit, lower RPM, more torque! - Rogue Fabrication
Probably the easiest setup for tapping is either your hand tapper or pull the plug on the DP and rig up a hand crank to the spindle.
BT Fabrication
Titanium
- Joined
- Nov 3, 2019
- Location
- Ontario Canada
magnetic drill. only kicker is its not a cheap option.
rustyironism
Cast Iron
- Joined
- Aug 31, 2012
- Location
- Lower Thumb, Michigan
Something like an Arboga drill press.
The several different floor models I have used had plenty of torque for tapping and also instant reverse.
I didn't care for the plastic gears in the drive train, but I suppose good as a weak link to protect the rest, but I never knew of a broken tooth on the plastic, either....
https://exactmachinetoolsales.com/assets/pdfs/arboga-a2608b-brochure.pdf
Mike
The several different floor models I have used had plenty of torque for tapping and also instant reverse.
I didn't care for the plastic gears in the drive train, but I suppose good as a weak link to protect the rest, but I never knew of a broken tooth on the plastic, either....
https://exactmachinetoolsales.com/assets/pdfs/arboga-a2608b-brochure.pdf
Mike
When I see "Get a quote" instead of a price I already know it's going to be expensive
NC Rick
Aluminum
- Joined
- Oct 7, 2007
- Location
- Asheville, NC
Damn, I don’t know much but we were doing 5/8” taps in blind holes on big printing presses either balancing on a beam or standing on a ladder. Bought a smaller Magnetic drill dress for drilling cast iron overhead. With the mag drill I needed ratcheting tap handle. I didn’t have a spring loaded tap guide right away, just a short piece of 1/2” drill rod I turned a 90 degree point on and followed the tap driver down.
Don’t overthink this, it’s basic. If you can afford a geared head drill press for this job, awesome, get one. I would love one! Total over kill. I bought a Starrett tap handle which I like and I have a guided tap handle for smaller taps. I can’t find a 5/8 tap in my junk which doesn’t have a center point. A pointy piece of steel in the chuck and an adjustable wrench and your golden. While it isn’t an issue to have it, you don’t need a 75% thread form in the hand wheel for a 5/8 - 11 thread. You are presumably not hanging a car off of it?
Don’t overthink this, it’s basic. If you can afford a geared head drill press for this job, awesome, get one. I would love one! Total over kill. I bought a Starrett tap handle which I like and I have a guided tap handle for smaller taps. I can’t find a 5/8 tap in my junk which doesn’t have a center point. A pointy piece of steel in the chuck and an adjustable wrench and your golden. While it isn’t an issue to have it, you don’t need a 75% thread form in the hand wheel for a 5/8 - 11 thread. You are presumably not hanging a car off of it?
