unknown tapping attachment

[dave george 1Participant @davegeorge1]

hi all

ive been given a unknown tapping attachment,there no name on it

does anyone reconise this,if so what size taps will this use

theres also a knurled part with numbers on

it looks it has two holders for taps at the front,and it also goes into reverse

when it reaches the end and its got a mt1

ive never seen this type of tapping attachment,so im clueless on how it works

and setting it up

[dave george 1Participant @davegeorge1]

[Clive FosterParticipant @clivefoster55965]

Don't recognise the make but if it reverses at the end of the hole the numbered ring probably sets the maximum torque. Mounts in a drill or mill. Feed down and the tap cuts into the material so long as the preset maximum torque is not exceeded. When the tap comes to the end of the hole the torque goes beyond the preset maximum which is sensed by the innards flicking the reverse drive setting in. Lift the quill on the drill by turning the handle backwards and reverse drive winds thew tap all the way back until it is spinning free. The grub screw on the side probably locks the torque setting.

The side to side slidy bit is usually in two pieces with a screw arrangement to close the two parts down onto the drive square on the tap. Usually there is a chuck or interchangeable collet arrangement below the sliding parts to centralise the tap by gripping the round shank. That one looks to only have a simple hole so only one size of tap can be accommodated, obviously collets or a chuck can take a range of sizes. Possibly its a production device with interchangeable ends.

Personally I'm not a great lover of these preset torque tapping attachments. Especially without documentation converting the numbers into real torques and appropriate tap sizes. Easy to se too much torque and break taps or too little torque so the hole doesn't tap fully. If tapping fails due to the torque setting being exceeded its safest to wind the tap right out and start over. Some breeds are fine about going back into drive if you move back a bit to clear the swarf and try again but some are not. Wouldn't like to guarantee things on a used one of unknown history. Worst thing is that you have to experiment with good taps to figure out the settings.

I have Pollard tapping heads which are essentially similar with chucks to grip the tap shanks and simple cone clutches for forward and reverse so the drive torque is proportional to how hard you pull on the drill handle. Sensitive tapping. Can still break a tap but then its operator error due to poor feel.

Clive

[dave george 1Participant @davegeorge1]

i forgot to say where the numbers are the knurled ring is stiff it dont move

 

edit 

 

after a quick google ive found this,which is simaler to the tapping attachment that i got

 

https://www.youtube.com/watch?v=r1rZ_M1Qnys

Edited By dave george 1 on 15/05/2016 21:55:28

[John ReeseParticipant @johnreese12848]

I have a couple of tapping heads similar to yours. At the moment I am a few miles away from them so I have to rely on memory. I believe the brand I have is SPV, made in sweden. If your tap head was used in industry it may be gummed up with dried coolant. A long soak in hot water may free it up. I gave mine a workout recently making some mini pallets. I probably tapped 200 1/4-20 holes. Almost forgot: I think the numbers on the knurled ring may represent tap sizes in mm. That is the way mine are marked.

[dave george 1Participant @davegeorge1]

Thanks for your comments john. Everything runs freely except the knurled ring with numbers,will have a closer look later

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