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Power Tapping in the milling machine without a tapping head
This some times unconventional tapping technique that has become mainstream
Watch as I demonstrates a method to tap on a Bridgeport mill
(this video is intended for apprentices and people new to machining)
https://youtu.be/aswbA9FT1vs
Ive taped many holes on mine.
Me too; but not with my drill chucks! Shops with the worst drill chucks are those where wholesale tapping is done with same chucks they drill with.Quote:
Originally Posted by marksbug
Taps are harder Rc then drill shanks; and gall the jaws when they slip, even more so at the top flats [drive square]. The evidence shows when a drill then slips, and upper end is burred more than other areas.
There are all kinds of economical tap drivers; comparable in cost to equal size quality chuck. I use the Hardinge TT; 5/8" shank Ø, less daylight needed to switch out and tap stays mounted. Favorite chuck is also mounted on 5/8" Ø shank.
Though, normal procedure is to locate and drill an entire pattern and return to coordinates that get tapped after chamfering, also dependent on quantities, size and other variables.
Expecting disagreement, but I'm not chipping out broken taps, scrapping parts, or needing to replace chuck jaws. And favorite chuck is a keyed Supreme; still holds many sizes just hand tight...
very well put
I do agree with you
in the in the environment of this shop (not a money thing)
we need to limit the number things in the space example there is only one coolant and only one oil
each piece needs to be painted a color for each machine
Ray
I used to see the guys in the shop thread holes using the floor drill press. They'd get the tap spinning at a pretty good rate, switch off the power to the drill press, and quickly bring the tap into the hole where the inertia would usually carry it on through, and I don't recall seeing broken taps. This all changed though when the shop foreman finally bought a Tapmatic.
I like normal tapping heads for drill presses, as few have reversing spindle, or too much inertia for a 'smooth' deceleration and reverse. The little Hardinge TT [including all the similar de-clutch drivers] don't need a torque arm [tommy bar] and are 1/3 or 1/4 overall length of ETTCO, Tapmatic etc. Can tap blind using depth stop by adding the .100 for the body to disengage pin driven collet holder. Cascao, homeengineer, Paul Jones..., can't recall who, made one DIY. A threaded body compresses a decent valve or die spring, threaded body adjusts the drive torque. [Excellent student project!] Also productive on lathes...engine, chuckers, turrets.
They all disengage while tap is down hole and feed lever is lifted. While body spins, tap is static. Can wait all day to reverse spindle.
Only 'drawback' is when many holes are encountered, via normal tapping head, increase RPM to back out tap. Serious time saving, easier on taps also, with proper coolant in play.
Not really finding much information on how the Hardinge operates, could you elaborate a bit? Does it require a reversing spindle to back the tap out? Is it viable for use in a drill press? I've got a Jarvis head but it's really too big for most of my needs and the Supreme Push/Pull I have is best suited for a hand drill, so I'm looking for a good, affordable solution for my drill press threading holes up to 3/8" or thereabouts. Is the Tapmatic 30x a good choice?
Morning Crusty!Quote:
Originally Posted by Crusty
It does need a reversing spindle, but...
The TT is pin driven...literally engaged or not, by a small [3/32?] pin, but no clutch adjustment. The body is 5/8" shank, would take an awful large daylight eating, centrifugal force generating, drill chuck. A better drive would be a Morse Taper end mill holder in 5/8". Shank's counterbored for SHCS, screwed into the closely fitted collet holder, and compresses the return spring. Had mine before even the Bandit Bridgeport 2 axis [X, Y & quill Z] CNC mills arrived, worked perfectly there too. A full set of collets hold #4 [or #6 ] to 1/2", don't think any tapper has that range or compactness. Conveniently [thank you, gods of standardization] metric taps are same shank sizes. Mine is currently mounted in a quick-change R8 Sandvik C6 holder. Sometimes I want tapping by coordinates, others I drag across on table. It is a semi-floating arrangement, allowing for some X-Y misalignment, with some linear too.
If the machine spindle advance 'falls behind' feed rate of tap, it disengages, just needs fingertip pressure on feed lever to reach depth. It does need a reversing spindle. On a chucker or turret lathe, reverse is a required feature, and feed depth are individual stops for each index, which is what they are built for. But it does fine on a mill too.
As you know, a Supreme works like machine tappers with built in reverse, after and during retraction. It's not a good idea to pump or peck a tap through like acceptable for drilling, due to chip evacuation. If tap does not reach intended depth; it is dull, ill-prepared hole, or inadequately sized tapping head.
Tapmatic 30 sized [lots of copies] will pull 1/4-20 in steel, maybe 5/16-18 in aluminum. Also, most tappers have clutch adjustment for driving torque. I start at lowest setting that will drive successfully; which becomes a monitor for tap getting dull.
Awhile back, debated finding a Supreme tapper for 240 tapped 1/4-20's in 10 foot lengths of 3/8" hot roll, borrowed a Tapmatic 30 instead. TT would've hindered that job, one hand needed to manipulate stock, another on the quill, can't reach reverse switch with my non-Pinocchio'n nose...Used mill and three outboard roller supports, a guide rail clamped over 1 Tee slot, holes positioned over the next slot to accumulate chips. Not counting set-ups, drilling and chamfering each side first, did 60 holes per bar in 9-odd minutes, with a single fresh R&N TiN tap and drip fluid.
I just went out and looked at my DP motor and it's a capacitor motor, so rewiring it for fwd/rev is a no go. Looks like I'll have to find a reversing tapping head to use it for threading. I'd like a tapper as short as possible because it's a bench DP and I want to give up as little headroom as possible. I'm open to suggestions of tappers you might know of that might fit my bill. I have used that Supreme Push/Pull successfully in my DP but it's a three handed PITA procedure.
I actually have a South Bend drill chuck on that DP which will hold 5/8" tools. Unfortunately the spindle end is a JT3 with no way to change it (hey it cost me $20 and it drills fine) so that limits how I can drive a tapper.
Yes, a couple road blocks vs cap start motor and J spindle...eventually I'll post reversible DP next to turret mill Bridgeport clone [mine is 5hp Comet], with a counterweight table to add out-feed perch.
Well waddya know. I just got into that motor and found that both leads from the starting winding are brought outside so I can wire in a reversing switch and that will allow many more choices for a tapping head.
I have what we used to call studder chucks... there gear reduction units we used in hand drills for reaming out valve guides for installing new guide liners, I ferget the name on them but I do remember one of them saying taping head....witch got me to:headscratch: I suppose it could be used for that....that may be the original application for them. Ill have to try it some day .they free wheel till you stop one portion.Im not sure but I reckon if you stop the other portion and let the first one spin it reverses. there is no internal clutch, just gears. I dont know if the one that says tapping head works the same or not, but they all look the same about 2.250" dia aluminum about 3"" long. Ill have to find them someday and see.I do think the "taping head one does operate a little different...or it could just be wore out more. I dont remember the make of them...or where there at. for our application they had a aluminum handle attached to them with piviot points so they were just a gear reduction unit fro driving reamers.
That's similar to the way that my Supreme Push/Pull tapper works - you hold one end to advance and the other end to retract but the quill handle has to have downward force on it or the tapper goes into center position neutral. It works good in a hand drill but in a drill press not so much. Now that I have a reverse on my drill press I don't have to look for a reversing tapping head so many more choices are available but most are too long overall so I may just stick to searching for drill press tappers which hopefully are shorter in length. That Hardinge which TM mentioned would also work now but I'd like to have gear reduction for tapping and maybe even torque limiting because broken taps have ruined a number of my days.
yes broken taps can make a nice day stink all to hell sometimes.
I'm not 100 successful with the 'Search' function, summoning up tags words is iffy too...
But these tap driving posts by homeengineer, JJRs and others address main issues. Tuomas's [1st one] is that spring modded clutch project I referred to earlier.
https://www.homemadetools.net/forum/...er-holes-63745
https://www.homemadetools.net/forum/...ing-head-68040
https://www.homemadetools.net/forum/...ut-close-71605
https://www.homemadetools.net/forum/...tuds-etc-65803
Broken taps? Yes, I do too. No one in my area advertises tap erosion, never saw one in a shop hereabouts either...The DIY versions work, but not 100% dependable, labor intensive, often tying up a machine as well.
Anyway, hauling a good sized Electro Arc back to be 1st call in that niche. I may offer burning to supporting HMTer's for cost; shipping, electrode portion, and electrolytic solution.
yes the tapmatic taping head you list is what I have ,I think probably 2 diferent versions. they are quite wonkey when worn.but like everything else a little work and back to good condition.
That "tapmatic" in the article is interesting but it is no where near a real Tapmatic (and they're priced accordingly).
yes I know Ive used real tapmatic's.
I just made a low ball offer to a guy on Ebay for a Greenfield tapping head and he accepted. Looks like I'm set up for smaller power threading now.
I dont send low ball offers, I send offer that I can/am willing to pay. if they call it a low ball offer then they have their stuff priced to high and want it more than I do. there will always be more. bidding wars are great for the seller but usualy not so good for the buyer, sometimes they are a good deal. I buy most of my stuff off flebay at great deals. it seems most of the high priced make offer sellers have the high price just incase they have a moron with tomuch $$ in his/her pocket wanting it...witch runs off real buyers that need it. and as a result they sit on many items too long. but a low priced right offer usually will buy it.
By low ball I meant at the bottom end of a fair price. When you're on a fixed income dollar bills matter and I almost never pay asking price because it's usually inflated for negotiating room. Sketchy, non-informative descriptions in the ad make me devalue an item too because I have to gamble that the item will work for me.
it seems a lot of people put extreamly vauge discriptions on stuff as well as some creatave photos' like putting a tape messure next to something at a angle and not even with an y part of the item to make you think it's bigger than it is. I really dont understand why they try to do that kind of crap.almost like bordering on scamming. I recently got some risor blocks that were done that way.when they arived they were close to 6" shorter than figured by the angles they took pic at&the angle of the tape messure.. it's was still a good deal but sure wooda been nice if they were "honest" with their pics. along with the cosmoline on the bottom that was rust...not bad but....oh well it is what it is.like the 5c er32 that came in today...cant use it as it isant like the one in the pic witch is like a std 5c collet with the interand extrenal threads. this one is almost solid. totaly useless. and the discription states..as pictured.. so..they owe me $$ or the correct one. and the fight starts now. most places will do the right thing but some dont.you never know.
I think sellers who deliver an item not matching the advertised description should pay a penalty to the buyer for wasting the buyer's time. Even if I'm fully refunded I'm still at a deficit for the wasted time and effort.
I've stopped buying things which don't clearly detail what's for sale. I've been searching for tips for an old oxy torch and of the sellers with some of these perhaps 1 in 25 shows a picture of the end of the torch tip (the most important aspect) so that I can see how many holes of what size are in it. Those don't make the cut for me. I think there's a lot of mook sellers on Ebay who are just selling stuff about which they have no knowledge, but a common dodge is to claim no special knowledge in the ad to put the onus on the buyer to determine from a few bad pictures if it's acceptable. Caveat emptor is still a good approach.
Identical to my fleabay modus operandi. Fun to undermine so many clueless bidders with fat pockets. Took some incredible auctions that way.
Such as that green ornament gracing the skyline shown in avatar.
PS to Crusty and crew; the sellers without decent knowledge loose a lot of money when us smart cats pounce on items. Once I decide/ calculate value to me, that's the limit. I'd bet that's not been jumped in my 700 something transactions. There are good clues telling wise bidder when it's time, or not.
Know what you mean - I got a set of resharpened Latrobe number drills in a General upright index for $22 plus shipping and it's improved my throughput quite a bit because it lives at the drill press. Seriously - $22 for a Latrobe number set - that's a sweet deal and the index was a bonus. No one else even bid on them.
Sure, there are between 2 and 5 generations who have NO idea what the stuff is for.Quote:
Originally Posted by Crusty
I use OfferUp also. Seems regional, but certain tools wind up on there. A tiny percentage compared to nonsense like designer sneakers, RC cars, drones, action hero movie paraphernalia, custom print coffee house thermal cups...