How do you keep taps straight?

[Bidgee]

I'm trying to tap a 1/2 20 thread into a reducer fitting I made (pic attached). I'm getting lots of run out. Is there a technique that minimises runout when using taps or is just practice? Some taps have centre holes in them which so a centre can be used to align them but this one doesnt.

I dont have a tool small enough to single point it although I could always make one I guess.

Thanks

Scott

[Stustoys]

Not much help now but you should have started the tap when you drilled the hole. Holding it in the chuck if you have to.(I have to because I haven't made a taping guild yet.)
Is it a taper tap? 1/2 20 should be easy enough to start once you have some practice. Do you have a proper tap spanner?
Stuart

[pipeclay]

Are you Tapping this in the lathe or vice.

what type of Tap Wrench are you using.

If you have a TEE type handle Tap Wrench and are using it in the Lathe there will or should be a Centre in the end of it,you can then locatate your Tailstock centre into this to keep the Tap square.

You could also try if using the Lathe a piece of timber placed against the end of the Tap or Tap Wrench held in place by the Tail Stock.

If you are Tapping this in a vice get your Set Square and place it on your vice to check the Tap for Vertical,check it in to Spots 90 degrees apart,you will have to check it every few turns of the Tap to ensure that it is Straight.

If you have a good eye after your intial check with the Square just Eye it every couple of threads at 2 spots..

If the item is Critical and you have no other means of getting the Tap square,make your self up a Tapping guide,virtually the same as a drill giude to locatate the Tap Vertical.

[pipeclay]

What size MM/or AF is a proper Tap Spanner.

[RayG]

Hi Scott,

Put the part in the lathe and use the tailstock with a center (dead or live doesn't matter) to center the tap, (the back of the tap ** or the T-bar tap wrench ** will have a locating hole) and use the tailstock feed to keep a little pressure on the tap while you turn the chuck or tap wrench by hand.. I usually turn the chuck, and the tap wrench handle will be stopped from turning when it hits the ways. (make sure power is off). Make sure you keep a little pressure on the tailstock feed as you feed it in.

Or, you can use either a mill or drill press to do much the same thing.

Regards
Ray

[Stustoys]

Oh and are you sure you have the right hole size?



What size MM/or AF is a proper Tap Spanner.
Anything with a T handle or two handles(i.e. a tap wrench)

He said his tap doesnt have a center guys

[Dave J]

It their is no centre it the tap, do as Ray said, but put the lathe in neutral with the part in the chuck, then hold the tap wrench while you turn the chuck by hand (using the chuck key for leverage if need be).

Dave

[Sterob]

Its also important to start with a taper tap. Some people try to take a short cut and just use the plug tap. The tapers sort of self-align and makes things alot easier......

[joe greiner]

Are you Tapping this in the lathe or vice.

what type of Tap Wrench are you using.

If you have a TEE type handle Tap Wrench and are using it in the Lathe there will or should be a Centre in the end of it,you can then locatate your Tailstock centre into this to keep the Tap square.

You could also try if using the Lathe a piece of timber placed against the end of the Tap or Tap Wrench held in place by the Tail Stock.

If you are Tapping this in a vice get your Set Square and place it on your vice to check the Tap for Vertical,check it in to Spots 90 degrees apart,you will have to check it every few turns of the Tap to ensure that it is Straight.

If you have a good eye after your intial check with the Square just Eye it every couple of threads at 2 spots..

If the item is Critical and you have no other means of getting the Tap square,make your self up a Tapping guide,virtually the same as a drill giude to locatate the Tap Vertical.

To assist in keeping the tap square in both directions, set up a pedestal-mounted mirror (usually sold as shaving or make-up mirrors) at one side or the other, so that you can glimpse the side view occasionally while also viewing the forward direction. Works for hand drilling, too.

Cheers,
Joe

[Bidgee]

Thanks for all the tips. I'll make the part again and tap it in the lathe before I finish it. The hole is the correct size.

Can anybody fill me in on what a tap guide looks like?

[Dave J]

Just another thought, how old is the tap?
If it is an old one it might be blunt, making you put a lot of pressure on it to get it going, which is making it off centerer.
I agree with Stuart about the taper tap, they are pretty well self aligning.

Here is a picture of a tap guide. If you search Goggle you will find all sorts of them. They are mainly for things as big as or bigger than the tap guide, I don't think they would be much good for your job.
http://www.woodworkforums.com/attachment.php?attachmentid=155095&stc=1&d=1291723159


Dave

[Stustoys]

With a 1/2" 20 if you leave the tail stock loose it will put it in.
There are heaps of different ones but here is one for starters.

Lathe Tapping Device (http://www.homemetalshopclub.org/projects/lathetap/lathetap.html)

Stuart

[azzrock]

um a taper or starting tap helps.right size hole helps hold the job in the chuck. the tap should be in a tap wrench. pointy end facing towards job and blunt end supported buy a centre in the tail stock. position the the compound slide under the tap wrench handle. rotate the chuck to wards your self with chuck key.the compound slide should be stopping the tap from turning via the tap wrench handle. remembering a suitable lubricant. carefully advancing the tail stock spindle as you turn the chuck. if you feel the chuck tightening up. reverse the direction you are turning the chuck 1 half a turn to break the chips. remembering to release the pressure of the tap with the tail stock but making shore the tap is still square.then rotate the chuck back towards your self. a ratio of 1 turn forward i half turn backwards is good till you get a feel for it. .this is a basic but sound way of tapping a hole im not shore of how standard or widely used it is.if this still doesn't work i would start to consider something is wrong. ie material to hard. wrong size pilot hole. tap us. ect ect. i hope i haven't repeated to much from above posts. and would be happy to help with any follow up quest.

[electrosteam]

Scott,
A couple of years ago I purchased a small 13 mm bench-top drilling machine from Aldi - $49 on special.
A classic Chindian heap of rubbish (Eg: quill splines loose beyond belief).

I drilled a few holes with it, then converted it to a tapping stand.
Removed the belts.
Made a handle out of 13 mm square tubing that mounts to a steel block sitting on the top of the spindle end clamped with a capscrew.

Chuck the taper tap, put job on table, adjust height with quill down somewhat (weight on handle) with tap engaged in hole to position the job, clamp job to table, then go at it.

The quill handle is applied downward to apply the necessary weight on the tap, and applied upwards to unload the tap when clearing chips.

For some materials and tap size combinations , the chuck cannot hold the tap tight enough.
When this occurs, release the chuck and transfer job, with tap now embedded vertically, to the bench vise for completion with the standard wrench.

Works a treat, best $49 I have spent.

On the "To Do" list is a chuck with a square engagement so that taps won't slip, but it has not been a problem to date.

John.

[Bidgee]

Thanks for all the tips and ideas. I re did the part tonight and clamped the tap in the tailstock with collet. As suggested I left the tailstock loose and turned the chuck by hand. Worked a treat and I now have thread with very little runout.

Appreciate the help.

Scott

[kwijibo99]

Tubal Cain (mrpete222) on youtube has recently posted a series of videos on using taps and dies. Worth a watch as he covers all the basics and several different techniques.
If you have a few spare hours it is worth watching all of his videos, he is an old school machine shop teacher and has clips on use of the lathe, mill, basic pattern making and casting just to name a few.
Cheers,
Greg.

[Woodlee]

For the drill press I made this set up.
The extension on the tap wrench slides n the socket on the morse taper

Kev

[azzrock]

hi im not shore if any one has mentioned this. with practice you can tap straight by hand.its easer with softer materials. you can adjust the angle the tap is to the work by putting extra pressure downwahds. on one handle of the tap wrench to correct and angle that may of developed. it works better with a longer handle tap wrench .. s/s and harder materials can still be difficult.

[Dave J]

I think he started out doing it by hand, but was after a more accurate way of doing it not having much experience.
I agree with you that with a bit of practice it can be done by hand just as accurate, it's just practice.

Dave

[glock40sw]

I use my taps in a battery drill with spirit levels on it.
Little bit of tap magic and away I go....woohoo.:2tsup:

[Bryan]

If I'm tapping in the bench vise I sit a square block of steel on the job. I can then sight it from two angles, 90* apart. Not both at once, I have to move my position repeatedly while I'm getting it started.

I used to think I had a good eye but I don't trust it any more.

[R W]

Have found that a taper tap will follow the hole, if the drill hole is straight you don't usually have to
much trouble, a good tap & tap wrench are also essential.