Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: clonk on October 30, 2009, 10:06:02 AM

Title: tapping and threading
Post by: clonk on October 30, 2009, 10:06:02 AM

"Another option is to drill and tap the shaft so that an extra long set screw can pass through the shaft and out the other end. This is my preferred method."


Do you use regular screws with a nut on the other end? Where do you buy your extra long set screws?
Title: tapping and threading
Post by: Admin on November 01, 2009, 10:31:17 AM
Quote
Do you use regular screws with a nut on the other end? Where do you buy your extra long set screws?
I avoid nuts if at all possible - they come loose over time. I buy my screws from mcmaster.com
Title: tapping and threading
Post by: clonk on November 02, 2009, 01:51:48 PM
I have never tapped a shaft though it seems real useful. I found this: http://en.wikipedia.org/wiki/Tap_and_die (http://en.wikipedia.org/wiki/Tap_and_die)

Do you do the die part as well? thread the set screw? Or do you just buy a set screw and then make a tap for it? Do you think I could tap with a hand drill or dremel? I have access to a drill press but it's like an hour away.

Thanks!
Title: Re: tapping and threading
Post by: Admin on November 02, 2009, 01:57:47 PM
Depends on what you are trying to do.

If I use plastic, I rarely tap before using a screw. Plastic self taps.

For aluminum, I drill a hole, tap it by hand, then simply screw in my screw.

I rarely use set screws.
Title: Re: tapping and threading
Post by: Gertlex on November 16, 2009, 03:53:00 PM
I have never tapped a shaft though it seems real useful. I found this: http://en.wikipedia.org/wiki/Tap_and_die (http://en.wikipedia.org/wiki/Tap_and_die)

Do you do the die part as well? thread the set screw? Or do you just buy a set screw and then make a tap for it? Do you think I could tap with a hand drill or dremel? I have access to a drill press but it's like an hour away.

Thanks!

You always do the tapping by hand power.  You have to relieve the stress on the actual tap as you go, or the tap will break, and then you'll have the fun of getting a broken tap out of whatever you're tapping.  This is done by turning the tap counterclockwise a bit after every half turn or so of clockwise tapping.

In metals harder than aluminum, and for deep holes in aluminum, you have to be concerned about tapping straight.  This can be done by starting the threading by placing the tap in a drill press's chuck, and then turning the chuck by hand.  And for any metal, you should be using some sort of lubricant (e.g. tap magic, but any sort of oil is better than nothing.)

The hole can be drilled in any of the usual ways.  (Though a Dremel generally isn't for drilling... especially holes that are deep enough to be tapped.

You get better with practice, too.
Title: Re: tapping and threading
Post by: SmAsH on November 17, 2009, 12:14:10 AM
You always do the tapping by hand power.  You have to relieve the stress on the actual tap as you go, or the tap will break, and then you'll have the fun of getting a broken tap out of whatever you're tapping.  This is done by turning the tap counterclockwise a bit after every half turn or so of clockwise tapping.
The rule i have always used is one turn forward, half a turn back.. Ive never broken a tap...
Title: Re: tapping and threading
Post by: Gertlex on November 17, 2009, 11:35:44 AM
You always do the tapping by hand power.  You have to relieve the stress on the actual tap as you go, or the tap will break, and then you'll have the fun of getting a broken tap out of whatever you're tapping.  This is done by turning the tap counterclockwise a bit after every half turn or so of clockwise tapping.
The rule i have always used is one turn forward, half a turn back.. Ive never broken a tap...

Ultimately, with a fair bit of experience, you'll get a feel for how fast you can go in a given piece of material :)

The really small taps are the easiest to break.  I've broken one or two of those.

Also, doing external threads on titanium with a Die is hard to do.  I gave up because it felt like I might do damage to the Die.