ME taps and dies

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Having spent hours on two steam chests using ME taps and dies Ive mucked them up.

I have had no problem with metric on sizes up to 8mm, all had good theads using my way of doing it.

The threads on the ME taps are so loose that to over come the problem I have used locktite and seems to overcome one part of the job.

The thread on brass ME 1/4 32. looked rather sharp, but using my die holder on the lathe the die was tight, I could not open the die up .

Measuring the die holder it was 20.5 mm, the die was the same size, checking the inch holder the M E 3/8 40 die was also tight, so I cant adjust the thread.

All my metric dies are loose in the die holder so adjustment can be made, I brought the taps and dies from a known supplier which supplies to the aero space industry so no cheap stuff.

I also had problems with taps all the holes on close inspection look crap, are there die holders that will take these dies, as Ive said I cant adjust them.

Tapping size 1/4 ME 32, 5.5mm    3/8 ME 32   8.6mm, as recommended by supplier.

Thanks, fed-up Bob.

 

 

Edited By BOB BLACKSHAW on 06/11/2018 11:35:59

[BOB BLACKSHAW 1Participant @bobblackshaw1]

[JasonBModerator @jasonb]

Funny enough I had an e-mail exchange with someone over the weekend who could not get a set of 3/8×32 taps to cut, could be some poor ones about. What make are the ones you have and what size (O/D) is on the box the die comes in.

I wonder if you have a metric die holders, it should be a bit looser than the OD of a metric die so about 25.5 for a 25mm OD die which could be why your imperial 1" die is tight and can't be opened up.

Edited By JasonB on 06/11/2018 11:43:48

[JasonBModerator @jasonb]

Just saw your edit, that was the same problem teh other guy had the taps would only go a few turns into a 8.6mm hole and jam, that was tapping steel.

Your smaller die may well be 13/16" which will not open up much in a die holder made for 20mm OD metric dies and it is unusual to find imperial threads in metric OD dies but you can easily buy metric threads with imperial OD.

[Anonymous]

The tapping holes sizes are too small. They represent thread depths of 85-90%. Given that the tap will slightly extrude material, and should be slightly over nominal size, it's not surprising the taps are binding. I'd drill at least 0.1mm bigger, for the 1/4" thread and 0.2mm bigger for the 3/8" thread.

Andrew

[JasonBModerator @jasonb]

Andrew, you know Fred, it was him and he could not even get the taper to go more than a few turns into an 8.8mm hole, though I did think it looked a bit iffy just before it gets to full form.

"I increased the hole to 8.8mm and the taps still will not go in. That is using a No. 1 first. I just don't understand Fred "

Edited By JasonB on 06/11/2018 13:30:03

Edited By JasonB on 06/11/2018 13:32:08

[Neil WyattModerator @neilwyatt]

Tubal Cain recommends 5.7mm for 1/4" 32 and 8.8mm for 3/8" 32.

Neil

[BOB BLACKSHAW 1Participant @bobblackshaw1]

I got the taps and dies from the Tap and Die company, they have a size chart on there web site.
Bob

[Anonymous]

I've got a couple of ME style taps from Tap&Die and they've been fine. I wouldn't pay any attention to the chart on the website. I'd put more trust in the figures in the book by Tubal Cain.

If Fred's taps don't work in a 8.8mm hole then I suspect the taps. Certainly the taper tap grind looks odd; almost as if the leading edge of what should be full depth threads has been ground off.

Andrew

[Howard LewisParticipant @howardlewis46836]

My ME 40 taps and Dies came from The tap and Die Company, and have caused no problems.

It could be that the problem with the male threads is using an Imperial Die in a holder intended for Metric dies. In which case there may be no scope to open up the Die.

With regard to lubrication, I use Rocol RTD for both taps an dies. Hand tapping involves backing the tap every half turn to break the swarf. (I learned the hard and expensive way, by breaking a M10 tap! They always break in the last hole)

Dies are usually used in the lathe, either using the "Jog" facility on the VFD, or a Mandrel handle. Again, if any doubt, back off to break the swarf, before it does some damage.

Howard

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Where can I get die holders to fit ME taps, or do I have to make my own, which I don't particularly want to do.

Bob

[JasonBModerator @jasonb]

Are you looking for a hand die stock or holders for a specific tailstock one?

EDIT if it is one of ARCs tailstock sets then you can buy a separate set of imperial holders to fit the body if you got the metric set with the body.

Edited By JasonB on 06/11/2018 17:43:58

[BOB BLACKSHAW 1Participant @bobblackshaw1]

I didn't realize that their was different types of holders, but the M 4mm die that I got from the company is tight on the the metric tailstock holder, its the same size as ME dies.

Bob

[JasonBModerator @jasonb]

Could still be Imperial OD as I said above

"it is unusual to find imperial threads in metric OD dies but you can easily buy metric threads with imperial OD"

[Mike PooleParticipant @mikepoole82104]

Die holders for 13/16 and 20mm are very close, they are often a bit oversize so a 13/16 die is going to be snug if it goes in a 20mm die holder but a 20mm die will be a bit loose in a 13/16 holder especially if it is a bit oversized, if it is too loose then there may be a risk of breaking the die.

Mike

Edited By Mike Poole on 06/11/2018 20:52:05

[Mark RandParticipant @markrand96270]

Umm, 13/16 and 20mm are 25 thou different. That's a lot if the diestock is metric and the die is imperial. Shouldn't be any risk to the die even in an oversize diestock if the two clamping screws are tight.

Question for Bob:- Is there a reason for not single pointing the threads?

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Mark, I only die max 12mm so no need for point threading.
My ARC tailstock holders only have two screws so no adjustments can be made.
Why only two screws on the ARC tailstock holders.
Bob

[Howard LewisParticipant @howardlewis46836]

If you want to hold taps in the Tailstock, the quick and nasty way is in a Drill chuck, but this is not advisable with ME 40 taps; the threads are likely to strip rather than drag the Tailstock along the lathe bed.

I made a Tap Holder, using ER25 Collets, to slide on the same arbor as my Tailstock Die holder. In this way the load on the tap is mostly that of thread cutting, rather than dragging a weight along as well

The collets needed to be surprisingly tight to grip the tap. But this has the advantage that if it hangs up, it slips rather than breaking. And having once started the tap , the job can be removed from the lathe and the tapping completed by hand, where you have a feel for how much torque is being applied.

Howard

[Neil WyattModerator @neilwyatt]

Posted by BOB BLACKSHAW on 07/11/2018 12:21:53:
Mark, I only die max 12mm so no need for point threading.
My ARC tailstock holders only have two screws so no adjustments can be made.
Why only two screws on the ARC tailstock holders.
Bob

Are they quite old?

These are Arc and have four screws:

Sorry for the picture quality, but the ones for my Arc turret have five:

 

Edited By Neil Wyatt on 07/11/2018 15:46:18

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Neil,
Mine are not so sophisticated as the photos, the ones I have are chuck held and three year’s old.
Bob

[Neil WyattModerator @neilwyatt]

Ah, I see them.

Perhaps they are originally designed to be used with non adjustable dies.

Neil

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Upgrade needed

Bob

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