Tapping

[John KinnaneParticipant @johnkinnane64270]

 

G'day every one and greetings from Tasmania. I am about to tap the 6B bolts into the sides of the stretchers on the Super Simplex, being so small a tap I was wondering if there is some "trick" to tapping the drilled holes. I have a follower and drill press and a mill if you could help me in how to do this accurately and how would be the best way to set the frames up so they are square while putting the stretchers between the frames thank you John

 

Edited By John Kinnane on 16/02/2017 11:41:57

[John KinnaneParticipant @johnkinnane64270]

Tapping small 6b bolts into the stretchers of the Super Simplex

[Peter SansomParticipant @petersansom44767]

Just make sure you use a thread cutting compound such as Trefolex. The tapped hole will be cleaner and less chance of breaking the tap.

Peter

[mechman48Participant @mechman48]

Make yourself a 'tapping block' to keep your tap straight… piece of squared up ally / brass / with hole just big enough to allow the tap to slide in, will start your tap off square. You could use your drill to same effect, providing you can guarantee the spindle is square to the table / vice.

George.

[John RuddParticipant @johnrudd16576]

George, his spindle would need to be square to the table to drill the hole thru' the block of brass/ally whatever….

But I know what you mean, just teasing….

I find tapping very small holes are a royal pain in the bottom, especially something like 10/12 ba…..I resorted to using the old spindle and chuck from a mini drill held in a collet in the mill, loose enough to enable it to be turned by hand……

Anyone else got a suggestion?

[mechman48Participant @mechman48]

As the question of drilling & tapping keep cropping up in MEW & as I have been browsing through my collection of tables I thought that I might include a couple of tables that can be copied & laminated for use in members workshops… I realise that most members will have handy access to their own ref tables, but for sticking on the wall next to drill / mill / lathe for quick ref… … especially for new members…

​George.

[John KinnaneParticipant @johnkinnane64270]

Thank you for your advice, it is much appreciated John

[JasonBModerator @jasonb]

As I tend to do most of my drilling in the mill I like to tap the holes at the same setting that they were drilled at which ensures the hole is directly under the mill spindle which can be used to guide the top of the tap.

I have a short length of 1/4" dia steel with a 60degree point on one end and ctr drilled the other so can support taps with or without a ctr hole. Just apply light pressure with the quill handle as you turn the tap wrench and ease off the pressure when backing off the tap to break the chips.

On small dia taps I tend to put the wrench on the round shank, that way hopefully the wrench will slip if things get tight long before the tap will snap.

[EmgeeParticipant @emgee]

plus 1 for Mechman's method but I usually face a piece of ally rod in the lathe and drill through to suit the tap diameter, put a few grooves in before parting off to suit the length of tap. After use put it in the tap drawer for future use. I suppose you could mill a flat on the side and stamp or engrave the tap size on, I use a permanent marker but without a flat !!!!

Emgee

[Neil WyattModerator @neilwyatt]

Posted by mechman48 on 16/02/2017 15:49:08:

Sorry George, I can't help smiling when I see you have scanned Presto's publication and then put your own watermark on it, presumably to deter scoundrels from copying it!

Neil

[mechman48Participant @mechman48]

Oops! mea culpa, totally unintentional please correct or delete, probably 'cos  as I resize jpegs FSResizer  auto watermarks everything, must remember in future, appreciate the heads up .

George

 

Edited By mechman48 on 16/02/2017 18:15:17

[mechman48Participant @mechman48]

…Duly amended…

Geo.

[Neil WyattModerator @neilwyatt]

Bang to rights, Guv!

[John Billard 1Participant @johnbillard1]

Just to add that with very small taps eg 10 or 12 BA I usually use a larger tapping hole than shown in the tables. Its worth experimenting with. Depends on the application as well. These small taps are not cheap and broken ends are the devil to remove. And remember to back off the tap as soon as it tightens.

Best wishes

John B

[John HaineParticipant @johnhaine32865]

Now I have a vfd on my mill I usually set the frequency to 10 hz, put the tap in the drill chuck, use the quill rack feed to just locate the tap in the hole, switch on the mill to thread the hole and reverse it when I've reached a reasonable depth, then finish with the tap in a normal wrench. No drama so far. When building an Ali box for my mill CNC electronics I tapped 20 or so M4 holes with the tap in my Bosch cordless drill with no problem.

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