Cordless Drill Guns for tapping

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beedlo said:
I am quite intrigued :bigeyes: after reading Peter Daniel's posts on tapping with a cordless drill gun with a clutch.
...
My question is: How can I pick a cordless drill gun that is suitable for tapping (among other things)? Is maximum torque a concern here?


Beedlo,

I guess you could begin with Home Depot and the likes.

I do it at the shop without any problems. Just chose a model that you can adjust the tork. Like Peter mentionned, I also use a Bosch model that has 24 levels of adjustments. The trick is to go slowly, so slow speed is an important feature. You go 2 or 3 turns and then back 1 turn and so on.

I only tap in aluminum so I don't know for other metals...

My .02$ (Canadian) :cool:
 
No... anything that needs a lot of torque you wouldn't be able to hold on to anyway, al least until you broke the tap.

Get a drill with two speeds. Drill on high and tap on the low range. Learn how to hold the drill straight so you can use a two flute tap... four flute taps (hand taps) are p00h ~ too weak because of the flutes and the flutes are too small for chips.

Torque limiting is kind of nice but ostensibly the torque is limited by the chuck's grip on the tap. I tapped about forty holes on a machine yesterday 1/4-20, 4, 5 and 6mm. Never used the tap handle once.

Tap breakage si a real pain. To avoid breaking taps, use a decent lubricant. For aluminum and steel a good product is Trim "Edge". It comes in a tooth paste tube. For plastics, use a houshold cleaner like Fantastik or Windex. If the workpiece is very critical (tapping is often the last operation!) move to a tap drill size that produces 65% thread as oposed to the standard 70%+. Fine threads are much easier to tap than coarse threads.
 
Any variable speed drill will work. I have used lots of different ones. Tap lubricant .... best I have used is bacon grease. Sure you can find expensive ones and they will work. About anything will do. Keep it straight and keep it moving. Backing up is ok for a hand tap operation. I don't back up unless it stalls. I have done thousands of holes in aluminum without breaking a tap and steel is easier yet.
 
value for the money??

Ya... when they decide they want to sell some drills, they have very good prices. Is there a better drill made, absolutely. Is there a better drill at the same price when Craftsman go on sale? That's a much harder question.

The same holds true with routers. Clearly the standard of the industry is the Porter Cable. But Sears invented the router business... i.e., every average Joe could afford the Sears router.

Favorite drill? Milwaukee 1/2" Holeshooter, two speed, hammer drill. Brace yourself! You can run it so hard that it gets too hot to hold on to.

Favorite sander? Porter cable 5" DA with hook & loop.

Bacon grease? You bet. A standard practice. 4% lard in kerosene. Great for aluminum but there are better things for steel.
 
You need to do the chuck up as tight as possible. If the tap slips, then after a few turns, enough heat usually generates to expand the tap enough for the chuck to grip it. If you are trying to tap 8mm, or 5/16"AF or larger, you may need to grind three flats (triangle) on the end of the tap. Unfortunately most of us have to do this by hand, (bench grinder) and damage can result to the chuck due to uneven loading. But a trades quality chuck can handle this.


Here is what I have learnt in 5 years of tapping with a pistol drill... up to 16mm in 4mm plate stainless steel... and frequently tapping diameter 4mm to 8mm in 10mm thick 316 stainless steel flat bar, and from 3mm to 8mm in aluminium

You have already bought a budget drill so your tap size is limited.

You need a sharp, high quality 'gun' tap for through holes, or a spiral flute machine tap.

For 'blind' holes, you need a spiral machine tap, so the chip comes out, like when you drill a hole.

Don't back up the drill, do the tapping in one operation, in and out. (Or you run the risk of breaking the tap if you accidently jerk it sideways from the torque-twist)

Use the speed that gives you a comprimise between good cut and good torque. (or the drill will stall) It is a feel thing. Hopefully you have a two speed gearbox, use the slow speed.

Let the drill and battery cool down if they get more than warm. Or you will shorten the life of both.

Use a good cutting oil. (not paste, as it blocks the flow of the chip)

try to square up the tap before you pull the trigger.

a good drill has at least 49Nm of torque.

This is just my advice, and it is different to what others have already written, so it is up to you to consider how you want to do it, and for you to learn from your own experience... but you probably already have before I even wrote this! :D
 
loonatron is correct on the tap slipage... after 1/4 it depends on the chuck and the material. A keyed chuck will be tighter. Otherwise, you really have to crank on a keyless chuck.

Make sure you are spending real money on real taps... the price is directly proportional to the quality and ease of cutting. You are not using four flute "hand" taps are you? You can't buy a decent tap in a hardware story or a grocery. Stop at you local industrial supply store.

Spiral taps are covered in the advanced class!
 
beedlo said:
I am quite intrigued :bigeyes: after reading Peter Daniel's posts on tapping with a cordless drill gun with a clutch.

A cheap (under $75) Chinese benchtop drill-press might also be an option for you. I use the drill-press as a tapping frame. The tap is chucked in & held 90-degrees to the work, you drop the quill w/ tap into the hole to be tapped, & manually turn the chuck by hand. For 1/4" or less aluminum, you can generate enough torque to easily go through it. If I need to tap something thicker & need more leverage (so far I haven't), I'd get a pin spanner to go into one of the chuck-key holes. The nice thing about doing it this way is that you can clamp your work to the table or make a jig to hold it.

Note, you do not turn the drill press on to do this operation!

speaker
 
I have followed some of the advices in this post, and I have been tapping quite successfully. Althought I was unable to find a spiral fluted tap until it was too late (*after* I got a normal hand tap); The hand tap was still sufficient however.

I have tried two methods to help myself tap square. One was to use a drill guide I made with two thin sheets of aluminum. It worked well. But I find that every hole I tapped with the guide, the guide would enlarge quite a bit. Perhaps a guide made with thicker, harder sheets, and some better fit bits would perform better.

The second method I used was with this:
Wolfcraft Drill guide (without the angle adjustments)

Tapping flat surfaces was very easy with this gadget. I am still thinking if it would be possible to use this drill guide to tap the end of a bar however...


There are two sizes that I am tapping with, M3 and M6. Tapping M3 holes was quite easy with the cordless drill; all my M3 tapping went through in one run. Tapping M6 proved to be a little more challenging. Occasionally, the tap would jam and I would have to back the tap up entirely and clean it. I use a nasty but effective solvent, Toyota Brake Cleaner, to quickly clean my taps. I strongly believe that brake cleaner should be added to the 'build the world' items like duct tape and zip tie. :bigeyes:

I understand that thread damage may occur when attempting to back out. What are some says to limit thread damage? How do I knwo the thread is damaged?

Again, thank you for all the help! ;)
 

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beedlo said:
I understand that thread damage may occur when attempting to back out. What are some says to limit thread damage? How do I knwo the thread is damaged?

Actually, if you use lubricant, you shouldn't damage thread when backing out. I'm backing out whenever I feel resistance, and all my threads seem to be fine. When the thread is damaged, at certain torque value, the screw will not hold and will go loose. There are still ways to fix it up though.
 
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