# Tapping - is this just the way it is?



## Maplehead (Jul 14, 2021)

Hi All
So a part I make has 48 holes drilled with a #33 bit. I tap them afterwards with a #6x40 plug tap. The tap has three flutes. The way I tap is I only turn the distance of the threaded section. So from flute to flute. That's 1/6" of the diameter of the tap. It's a very small amount and very slow. Each time I turn forward I turn back about a half to a full turn. (Chip removal? I don't knowas I can't see what's going on in the hole.) Anyways, this takes forever to tap a single hole 5/8" deep, and then I have 47 more to do after that. So... is this just the way it is? I can't break a tap in the piece as they are impossible to get out and so I just scrap the piece and have to start over.
All replies/advice is greatly appreciated.


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## T Bredehoft (Jul 14, 2021)

Find/purchase a "Spiral Flute" tap, the continuous chip comes out the back. no more start/stop/reverse action. Or, if  the hole goes through, get a "Spiral Point" tap, sometimes called a "gun" tap, it shoots the chip ahead of the tap.


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## Weldingrod1 (Jul 14, 2021)

A thread forming or rolling tap would be a good choice if your material is ductile and not sticky. Looks a bit like a woodscrew: no flutes. Wonderful on Aluminum!

Sent from my SM-G892A using Tapatalk


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## Maplehead (Jul 14, 2021)

These are all through holes. Wouldn't a forming tap not work since the holes are so close to each other? I imagine a forming tap pushing into the other hole space.
Never heard of a spiral tap. Will check out.


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## Lo-Fi (Jul 14, 2021)

Starting with a plug tap is going to lead to some pretty high cutting forces. On threads that small I'd go taper, or at least second tap, then back with the plug tap if you're doing blind holes? EDIT: just seen you're doing through holes, so ignore about running the plug tap through. 
As mentioned, throw some money at a spiral flute tap, they're so nice to use! They're all I buy now. Lower cutting forces again than the straight flute taper tap.


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## Winegrower (Jul 14, 2021)

I am going to switch to thread forming taps for smaller than 1/4”.    They seem way less likely to break.   And the forming taps I have do include a sort of meager flute-like groove.  They just work terrifically, with no reversing, no chip buildup, and so far no breakage.

The normal tap drill sizes don’t apply, so look around for a forming tap drill chart.


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## mattthemuppet2 (Jul 14, 2021)

I'm always a bit leery of using form taps in steel, but there's no reason why you can't. Precise hole size is pretty important though.

For your piece though I'd get a spiral point tap with a neck length (before the shank) that's a bit longer than the thickness of your work piece, then power tap on the mill or drill press if you have reverse. If not, get a tapping head 

I'm making some QCTP holders, each has 4 1/4-20 holes for set screws. Drill all 4 holes, then countersink, then tap each one, takes probably 20min at most including tool changes.


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## jwmay (Jul 14, 2021)

No help here, but tapping holes is another of my many completely disheartening failures. Today I drilled and tapped one M6 threaded hole. My tap drill was broken so I resharpened it by hand and eye. The tap was new and went in so smoothly that I nearly reached into my other set to throw away the other tap that I've battled for so long. THIS was confirmation that that other tap was pure crapola! Then when I put a screw in it I found that my hole was oversized, and the screw just wobbled around inside the hole. So whatever effort was involved was pretty well wasted effort.  Like I said... no help here... but you're not alone. I'll try this special tap too, but in my case, I think it's just me.
Whatever that thing is you're making is pretty. Looks nice!


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## Maplehead (Jul 14, 2021)

I ordered four spiral taps. Like I said, I don't think form taps will work for me as I think the holes are too close to each other and the form tap will just push the grooves into the adjacent hole. jwmay, you're not alone. Tapping is a PITA. I have the feel now so I can go for a while without breaking taps but doing so creates a very slow process. The part you're looking at is a tool-less electric guitar bridge.


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## Eddyde (Jul 14, 2021)

If you are planning on making many of those guitar bridges it would pay to purchase a tapping head for your drill press or mill. With a spiral point tap mounted on it you'll be able to tap all those holes in minutes.


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## Karl_T (Jul 14, 2021)

You might want to look at power tapping. Actually breaks less taps. This offer can be found used for a fraction of new price



			https://www.mscdirect.com/product/details/09470055
		



I also power tap with a collet right in the knee mill. Bit of a learning curve here and you need an easy instant reverse - I use a VFD with resistor brake.

several offers on ebay:








						procunier tapping head for sale | eBay
					

Get the best deals for procunier tapping head at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!



					www.ebay.com


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## SLK001 (Jul 14, 2021)

Tapping really isn't hard - you're just making it so.  A plug tap is NOT the way to start a tapped hole.  A TAPER tap is used to start a tapped hole and can be used for the entirety of a thru hole.  Are you supporting your tap, or is it all just freehand?

And, what is that thing you're making?


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## Maplehead (Jul 14, 2021)

I have no issues with the plug tap, starting and free hand and all. My threads come out very nice. My issue is just the time it takes to do. It's like twenty minutes a hole. I need to look into these tapping heads some of you mentioned.


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## Eddyde (Jul 14, 2021)

You'd be able to tap all 48 holes in less than 20 minutes!


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## Maplehead (Jul 14, 2021)

Eddyde said:


> You'd be able to tap all 48 holes in less than 20 minutes!


I would love that.


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## Eddyde (Jul 14, 2021)

Maplehead said:


> I would love that.


Watch the video I posted on the previous page.


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## vtcnc (Jul 14, 2021)

Tapmatic. You won’t look back.


Sent from my iPhone using Tapatalk


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## matthewsx (Jul 14, 2021)

At one of my first jobs working for the Crain Carpet Cutter Company of all places I ran a drill press with a tapping head. Yes, that's what you want if you're building more than one of these. 

Guitar bridges? Cool, I've built a few bass guitars, one neck but never a bridge....

John


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## Ulma Doctor (Jul 14, 2021)

looks like you need a tapping head


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## Brento (Jul 14, 2021)

What are you making there?


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## jwmay (Jul 14, 2021)

Could have sworn I left a comment here. Weird. Well I must have replied to someone else's thread on accident. I bet they think I'm off my rocker. Anyways, that's a neat looking part. I don't have any advice though.


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## brino (Jul 14, 2021)

jwmay said:


> Could have sworn I left a comment here.



It appears that there are two copies of this thread......this one and that one:
https://www.hobby-machinist.com/threads/tapping-is-this-just-the-way-it-is.93956/

-brino


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## jmkasunich (Jul 14, 2021)

Maplehead said:


> I ordered four spiral taps.


Be careful with the nomenclature here.  There are spiral flute taps and spiral point taps - very different things.  See pics below (shamelessly stolen from McMaster Carr's website).

Spiral flute have spiral flutes just like a drill bit.  They are for blind holes, they bring the chips up out of the hole so you don't have to stop and reverse to break chips as you do with a hand tap.  However, they are more fragile than hand taps and need to be used with care.


Spiral point taps have a short spiral section ground at the very tip.  This pushes the chips forward.  They can't be used in a blind hole (unless the hole is very deep and you don't mind leaving it full of chips).  But they work great in thru-holes.  Don't reverse to break chips - just keep turning and a continuous chip will be ejected out the bottom of the hole.  Spiral point taps have a little more beef to them than a hand tap (flutes are shallower) and are a bit less likely to break.  That combined with no need to reverse and break chips mean they are the bees knees for thru-holes.


I use spiral point wherever possible.  I haven't bought a hand tap in years, spiral points are only little more expensive and so much nicer to use.

McMaster Carr sells a plain HSS spiral point #6-40 for $7.41, or a TiCN coated one for $10.91.  If your part is steel I'd spring for the TiCN.

As others have mentioned, a tapping head would really work great for this project.  Of course you need a spiral point tap if you are using a tapping head - using a hand tap in a tapping head is pointless, the chips won't break and the tap will.  A tapping head will set you back a few hundred bucks but if you are making lots of these it will pay you back pretty quickly.

Also very important - make sure you are using a suitable lubricant or tapping fluid!

One final thought - the tap drill chart is a recommendation, not a gospel.  For a #6-40, the chart says #33 drill, and says you'll get about 75% thread depth.  Do you really need 75% thread depth in your application?  Maybe going one size larger with the drill will make it tap easier, and still be plenty strong for your parts.  Try it out on a piece of scrap and see.


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## mattthemuppet2 (Jul 15, 2021)

I go for 50% thread in steel, especially stainless, makes tapping so much easier and I've never had a thread fail (touch wood)


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## Maplehead (Jul 15, 2021)

It appears that a new Tapmatic tapping head is around $700. Are the used ones on eBay considerable? I usually shy away from used as you never know how much the wear effects operations/results. However, used is $350 down to $75. Your thoughts?


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## stupoty (Jul 15, 2021)

Maplehead said:


> It appears that a new Tapmatic tapping head is around $700. Are the used ones on eBay considerable? I usually shy away from used as you never know how much the wear effects operations/results. However, used is $350 down to $75. Your thoughts?


There is a uk brand (old second hand only) that is even cheeper , I think the tapmatics have a reduction gearbox which the type I have doesnt.  Uses some sort of fiber (aparently card not asbestos  ) for a friction clutch.

Payed about £35 some times worth a punt on s/h if it's a massive saving.






Stu


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## machPete99 (Jul 15, 2021)

If that is a guitar bridge I think you would be much happier with a linear adjuster for intonation.
This design looks like it would make intonation adjustment rather difficult.
There you go; no more hole tapping problem!


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## Papa Charlie (Jul 15, 2021)

Maplehead said:


> It appears that a new Tapmatic tapping head is around $700. Are the used ones on eBay considerable? I usually shy away from used as you never know how much the wear effects operations/results. However, used is $350 down to $75. Your thoughts?


 Like most tools, the used, provided they have been taken care of, are just as reliable and robust as the new ones. Often, used may also mean made in USA or Japan or the like instead of China or India.


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## Maplehead (Jul 15, 2021)

My earlier designs had linear adjustment but they were a PITA. The whole idea of this bridge is that it's tool-less for adjusting action and intonation. It works and sounds really good.


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## Eddyde (Jul 15, 2021)

Good deals can be found on eBay, You have to read the description carefully and ask questions if necessary. Also be sure the seller offers a refund. Many years ago I bought a couple of used tapping heads at an auction. They came from a production shop and looked like they had heavy use. I opened them up for a good cleaning expecting to find a horror show, but I was surprised to find the oil clean and the gears showed almost no wear. I still use them without any issues.


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## brino (Jul 15, 2021)

Maplehead said:


> It appears that a new Tapmatic tapping head is around $700. Are the used ones on eBay considerable? I usually shy away from used as you never know how much the wear effects operations/results. However, used is $350 down to $75. Your thoughts?



Be sure to get one that includes all the collets for different sizes of taps. It may be difficult to find those after you buy the tapping head.
-brino


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## extropic (Jul 15, 2021)

I'm concerned about the spacing of the tapped holes.
Do the threads of adjacent holes intersect? In other words, what is the design wall thickness between adjacent tapped holes?

If the threads intersect or if the crest to crest wall thickness can be less than .015", I think I would tap every other hole. Then install a threaded member into each tapped hole, for support. Then finish tapping. If the threads overlap (zero wall thickness) the threaded member should not be harder than the workpiece. If there is a guaranteed wall, I would use socket set screws.

My thinking is that the cutting forces will deform the hole at the thin (or non-existant) wall, resulting in on out-of-round condition and a higher risk of breaking a straight flute tap.

A spirol flute tap should be much less influenced by thin wall.


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## Maplehead (Jul 15, 2021)

I know nothing about how this will react under power threading. However, I have done a few of these via hand tapping. The holes are super close to each other. After I tap them I then take a 1/16" end mill with a 5/8" cutting length and I slot the columns. This is to allow the strings a space to travel through to where they anchor below. After I slot the columns I re-tap the holes to fix any deformities. So far everything has worked out fine. How this will go under power tapping is anybody's guess right now.


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## Papa Charlie (Jul 15, 2021)

It will work fine and you will love a spiral tap and a tapping head.


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## Maplehead (Jul 15, 2021)

I purchased a used Tapmatic 30X. Now I'm looking for the correct tapping bit. #6x40 spiral point I gather, with the super coating.


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## Janderso (Jul 15, 2021)

Eddyde said:


> Watch the video I posted on the previous page.


That is one cool gadget!


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## Maplehead (Aug 3, 2021)

UPDATE:
So I bought a used Tapmatic 30X. This afternoon I tried tapping those 48 holes, #6 x 40 with the recommended taps you all mentioned.
Holy Moly!!! This tool has got to be the coolest ever. What used to take 15 hours by hand and was nerve racking wondering if every turn I was going to break the tap has now become an easy peasy quick deal. I did all 48 holes in under 20 minutes. I say to anybody considering one of these - get it, you will not regret it.
Thanks to all that recommended it.


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## Winegrower (Aug 3, 2021)

Yep, a tapping head is terrific.   I have a Procunier 2E, and as Brino mentioned, it can be a hunt to collect a full set of collets.   However, it’s an amusing project to make your own, with the only tricky part being an internal square hole holding the end of the tap.


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