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View Full Version : Need turret tapping advice...???



torker
03-01-2008, 11:07 AM
Hey guys! I may have stumbled on a way to make this lil' lathe make some serious $$$.
Trying to figure how to do it...I need to drill and tap metric blind holes about 1 1/4" deep in the ends of 6061 round stock. No big deal to do it manually.
But to do it on the turret machine?
A stickler.. I need to do right hand thread on one end...left on the other.
I can find the right hand metric taps ok...but which ones will work the best on a turret machine? There's a lot of different taps for alu...what would you recommend?
The left handers may be a bit harder to find. I can find regular style lefthand taps but, as with the right handers...I'm not sure what style to use for power tapping that deep in alu.
I'm thinking of making a couple of releasing tap holders like JT showed us.
Thanks!
Russ

Duffy
03-01-2008, 11:15 AM
Just a suggestion, but why not e-mail Alcan, (some tech support or other,) and ask them. My guess would be some type of gun tap as long as the hole is deep enough to accept the chips at the bottom.

mochinist
03-01-2008, 11:20 AM
I can't help with the turret lathe portion, but a roll form tap would work nice for this and you wouldnt have to deal with cleaning out any chips in all those holes.

torker
03-01-2008, 11:33 AM
Duffy... have you looked in a catalog like KBC for aluminum taps? There are so many...hi-helix this and spiral that...high chip evac etc. I have no idea which to pick. Then there is the left hand aspect...that'll be sure to cut down on the choices.

torker
03-01-2008, 11:35 AM
Thanks Mo..I'll go look at the catalog and see what you are talking about :D
That's what I'm after..something that'll eject the chips.

Duffy
03-01-2008, 11:56 AM
Torker, I just checked a little handbook by Dormer and it recommends Cold Forming taps for aluminum "wherever possible." It further states that a 60% thread will have essentially the same strength because the threads are produced with unbroken metal grain fibres. They also state that different drill sizes are used than those for cut threads. Dormer has a western warehouse in Vancouver, (it says on the back cover.) A bonus is that chips are not an issue.

mochinist
03-01-2008, 11:56 AM
Thanks Mo..I'll go look at the catalog and see what you are talking about :D
That's what I'm after..something that'll eject the chips.There is no chip with a rollform tap, it literally forms the thread instead of cutting it, just pay attention to the drill charts for them they dont use a standard sized drill that would be used for a cutting tap.

tattoomike68
03-01-2008, 11:58 AM
Roll form taps do such a good job im supprized more people dont use them. They are alot sronger than a cutting tap.

torker
03-01-2008, 01:15 PM
OK...Thanks guys!
I looked at them in the catalog. Didn't recognize the name as they call them Cold Forming taps.
I got you!
A question though...you do have to different drill sizes obviously and as Duffy says..60% but the thread is as strong???.
Ok...these are for steering components with metric threads. Am I seeing any problems here when compared to a full depth cut thread?
Thanks!

Oldbrock
03-01-2008, 01:26 PM
Take a look at this Russ http://www.bilzusa.com/Products/Tapping/TA.aspx
Looks like this would fill the bill with a straight 3/4 shank. Peter

torker
03-01-2008, 01:40 PM
Peter...I have one of those on my drillpress. This smallish Weiler turret doesn't have a lot of room for that...plus I'd need a left hand one also...lol!
The rods I'll be tapping are anywhere from 12" to 18" long.

moldmonkey
03-01-2008, 02:19 PM
Here is a compression-type tap holder I made for my second-op lathe. It requires plug-reversing which wouldn't work as well when tapping to a certain blind depth as the self releasing type but works well for through holes and starting threads and finishing by hand. Spiral flute taps work well for blind holes.

http://img.photobucket.com/albums/v476/moldmonkey/P1010134.jpg


http://img.photobucket.com/albums/v476/moldmonkey/2008-01-01SD091.jpg

Edit: On the % of thread, form vs cut threads for steering components. Don't ask us, ask the customer. You are talking serious liability issues there. If it's made to the customers specs, you should be fine.

DR
03-01-2008, 02:57 PM
The tap drill size for forming taps is much more critical than for a cutting tap. Sometimes we have to ream the hole to size if there isn't a standard drill of the correct size or if the drill is tending to run oversize.

1-1/4" deep?? What size tap are we talking about? I've had occasions where the tap won't go that deep (on small sizes). In that case we grind the tap down in diameter behind the flutes to allow deeper penetration.

torker
03-01-2008, 06:31 PM
Jon, I like that tapper you made.
Ask the customer...Ummm...ok, I'll ask a bunch of redneck sledders who don't know a tap from a Budweiser. That's why I asked here.

Steering components... They make these things so flimsy nowadays you can't believe it. THESE ARE NOT FOR YOUR GRANNIES CAR Btw..
They've cut unbelievable amounts of weight out of these new snow machines(have a good look at a modern mountain sled). Now it's starting to show. I have a steady stream of guys coming in here looking to replace broken/bent parts for brand new $15000 sleds.
The new factory parts are incredibly expensive and fragile.
The things I'm making will be beefier...like the older sleds and half the price.
I'm not worried about liabilities... I just want to make sure proper machining is followed.
DR.. I can't tell you yet what size the holes are. Reason.. my metric thread guage hasn't got here yet. The rod ends that thread in are about the same size as 3/8" Imperial.

John Stevenson
03-01-2008, 06:38 PM
Russ,
Whilst you are waiting for your metric thread gauges here's the nearest to 3/8" which is 10mm, is this close ?

▲▲▲▲▲▲▲▲▲▲▲▲▲▲

▼▼▼▼▼▼▼▼▼▼▼▼▼▼

.

mochinist
03-01-2008, 06:41 PM
Jon, I like that tapper you made.
Ask the customer...Ummm...ok, I'll ask a bunch of redneck sledders who don't know a tap from a Budweiser. That's why I asked here.

Steering components... They make these things so flimsy nowadays you can't believe it. THESE ARE NOT FOR YOUR GRANNIES CAR Btw..
They've cut unbelievable amounts of weight out of these new snow machines(have a good look at a modern mountain sled). Now it's starting to show. I have a steady stream of guys coming in here looking to replace broken/bent parts for brand new $15000 sleds.
The new factory parts are incredibly expensive and fragile.
The things I'm making will be beefier...like the older sleds and half the price.
I'm not worried about liabilities... I just want to make sure proper machining is followed.
DR.. I can't tell you yet what size the holes are. Reason.. my metric thread guage hasn't got here yet. The rod ends that thread in are about the same size as 3/8" Imperial.Good article on them Torker

http://www.sme.org/cgi-bin/find-articles.pl?&04apm002&ME&20040401&&SME&

Duffy
03-01-2008, 07:18 PM
Torker: It would appear that John is right and it is a 10x1.5. Normal drill size is 8.5 mm or Q. For form tapping, Dormer says 9.3mm and the nearest imperial is U (9.35mm.) To quote the handbook "Cold forming as opposed to cutting, produces threads with unbroken metal grain fibres. The threads are therefore stronger, and the normally accepted 75% thread produced with cutting taps can be reduced to 60% without loss of strength." If this prooves to be the way to go, then you would want one LH and one RH would you not? I understood that any more thread depth than about 1.5 diameters was a waste of time and effort.

mochinist
03-01-2008, 07:31 PM
I understood that any more thread depth than about 1.5 diameters was a waste of time and effort.Was taught the same thing, but maybe the thread depth is for adjustment if this a steering application.

torker
03-01-2008, 07:37 PM
John...yes they are 10 mil. I just have no clue as to the pitch.(read metric dummass).
You know we still have two machine shops here...if you mention metric to them they ask you to leave the shop :D
I have to get with the program on this end. All the sleds and bikes I have..I need all this stuff. A metric helicoil kit will be a bonus in this business.
Mo..Thanks! That was a good read.

torker
03-01-2008, 07:40 PM
Yup..Mo got it. These use two rod ends for toe in/ toe out adjustment.

J Tiers
03-01-2008, 08:44 PM
Don't thread forming taps take more torque to do the work?

While the releasing tapper works either way, LH or RH, it is dependent on the way you hold the tap for the torque transmission to do the cutting/forming.

A 10mm tap could take serious torque to turn for EITHER cutting or forming, but I'd guess forming takes a bit more. Especially when you get that deep.

I did 5mm to a depth of 3/4"(18mm) in aluminum, but 75%, and there was a decent amount of torque to do that, cutting.

The depth seems to be the issue, and with a forming tap I'd expect problems with it that deep. All that length rubbing. Could be a problem. I'm more familiar with forming for more shallow holes, but that was as a specifier/purchaser, not doing the work.