Thread Bare

Can anyone tell me if there is an easy fix to the following

I have just drilled and tapped M6 holes with a M6 x 0.75 pitch tap.

I bought M6 studding which will not screw into the new tapped holes. I’m guessing the studding in M6 with 1.00 pitch ?

Is there an easy fix ?. Could I re tap the existing holes with a M6 1.00 pitch tap ( which I will need to buy)

Can you not buy/make some M6 x 0.75 studding?

It's really new studding which you are unlikely to be able to buy in the finer pitch or new holes drilled with a smaller drill that you used for the fine thread and tapped M6 x 1.0

If the job is really lightly loaded you may get away with putting the coarser tap through but even then there is a risk of the studding pulling out particularly if the hole is shallow but given the fact most off the shelf studding is undersize I don't think I would risk it.

Edited By JasonB on 01/07/2019 17:33:15

I think retapping will come close to leaving you with a 6mm hole, helicoiling could sort the problem if you want to go to M6x1 but that is not too cheap unless someone can do it for mates rates. If studding with the right pitch is available then the problem is solved.

Mike

Easy fix >>> **LINK**

https://www.stainlessautomotivefastenings.co.uk/index.php?main_page=product_info&cPath=565_31&products_id=9356&zenid=8clu4v44nph1oci9fopgcee430

MichaelG.

.

But not easy on the wallet 

Edited By Michael Gilligan on 01/07/2019 18:04:40

Studding in metric fine may be hard to obtain, if there is sufficient wall thickness, then helicoils are much easier.

Check out ebay listing 173833058997.

 Michael Gilligan's post shows a source, but it is very expensive for only 25mm lengths.

Edited By old mart on 01/07/2019 18:08:59

M6 x 0.75 studding is available on eBay from China/Hong-Kong for nominal prices if you're willing to wait that long (and if you haven't forgotten why you wanted it when it finally arrives).

If you only need a short length you might be able to cut the head off a screw.

Edited By Bandersnatch on 01/07/2019 18:24:11

To make studding quickly and easily take a look at this:

YouTube video

Edited By Hollowpoint on 01/07/2019 18:43:07

Hi where in the country do you reside I have some helicoil taps if you think it would help. You have to have enough metal round the thread to cut the oversized thread and when done it us just as strong and in alloy stronger.

David

I think I'd rather use grub screws than cap-heads to hold the die though.

Bill

If you really want to make studding rather than making new bits with M6*1 thread, the consider making a diestock which you can clamp in the tool holder. Adjust height and in/out to get it central. Set the change wheels or gearbox for the right pitch and away you go. Doing it as shown in the video will almost certainly result in pitch error, which might not matter of course

Once the die holder leaves the guide it does have a bit of wobble but if that is not a problem then it is certainly quick. I think I would go with Duncan’s plan that does not involve any living clamps.

Mike

I agree far better not to hold the die-holder under power, but in fairness at least the OD of the holder is smooth so less likely to cause injury.

Unlike the tang of the file he uses to put a chamfer on the end of the rod! V. dangerous.

On 2nd thoughts after closer examination there is a handle on the file. I withdraw my complaint

John

Edited By Journeyman on 02/07/2019 10:56:47

If your worried about filing in the lathe(handle or no), hold the file under the work, with the handle pointing to the back of the lathe, if things get caught up for some reason the file will go away from you.

Ian S C

Going back to the original post asking about an easy fix, the answer is dependent on what Garry considers easy, but more importantly, what is the actual purpose of these holes and studding.

If its not essential to have long lengths of stud projecting out of the holes than why not just use screws or bolts with the finer thread, not as much available as in metric coarse but still enough around to chose from.

From the picture the lathe looks to be a woodworking lathe so its unlikely to be ideal to make studding. Is the 6mm diameter a limit, I wonder whether the holes be rethreaded to M8 (or M7) and larger studs used, alternatively it would also be possible to make inserts with M6 internal thread and a larger external thread, say M8.

Ian P

Helicoil kit would be my choice.