cutting metric fine thread

[garrygunParticipant @garrygun]

Hi guys,i normaly use cobalt for cutting threads, this time i decided to buy a holder with tct, never used one before.

forgive my ignorance.

how do you align the thread with this holder?

also what depth would a 0.75 metric pitch be?

its not in zeus also looked at another guide but no depth shown.

Thanks Garry

[garrygunParticipant @garrygun]

[Harold Hall 1Participant @haroldhall1]

You will find the info re thread depth in the Metalworkers Data Book. number 42 in the worshop practice series. It has 215 pages which contain a wide range of data.

Regarding metric fine it covers from M1 x 0.20 to M24 x 2.0. It gives amongst tapping drill sizes, etc. outside diameter and core diameter, depth of thread with be half the difference

Harold

[garrygunParticipant @garrygun]

Posted by Harold Hall 1 on 16/09/2012 20:39:07:

You will find the info re thread depth in the Metalworkers Data Book. number 42 in the worshop practice series. It has 215 pages which contain a wide range of data.

Regarding metric fine it covers from M1 x 0.20 to M24 x 2.0. It gives amongst tapping drill sizes, etc. outside diameter and core diameter, depth of thread with be half the difference

Harold

Thank you harold, i will be ordering one, but the delivery time is slow, so by the time i receive it, it will be about 21st. next friday if im lucky. so i will have to put it off till then…

[Clive FosterParticipant @clivefoster55965]

Garry

Thread depth for a given pitch is constant regardless of the diameter. So simply look up 4.5 x 0.75 mm in the Zeus book and read off the depth there. 0.4601.

Of course the actual cut depth depends on whether the insert is full or partial profile. Full profile just go to the book depth, partial needs to go a little deeper depending on the thread range covered. Partial profile specifications should be in the insert data book or you can figure it out from scratch starting with the thread range. A drawing helps.

Sometimes you can use a normal threading set-up gauge, usually only the smallest notch will go. Insert and holder data book should help you with alignment issues. Many are made so the thread form on the insert is parallel to the shank of the holder so its easy to align the holder. Aligning the holder is normal practice with the Johannson / SKF chasers I prefer. Unfortunately they are getting very hard to find.

Clive

[garrygunParticipant @garrygun]

Thank you clive for your knowledge, that has helped very much.

i aligned the cutting tip up to a guage it was bit fidly but i got there in the end, i didnt check to see if the holder runs parallel with the cutting tip, i will check this later ,if it does i will remember this for future, it will be so much quicker, i did have a dummy run,looks good so far 2 more passes should do it, then for the real thing…

Thanks Garry

[Ian S CParticipant @iansc]

To line up the tool, I use one of those little fishtail gauges, I'v got one for 55deg, and 60deg, these make setting up simple. Ian S C

[garrygunParticipant @garrygun]

Posted by Ian S C on 18/09/2012 11:49:21:

To line up the tool, I use one of those little fishtail gauges, I'v got one for 55deg, and 60deg, these make setting up simple. Ian S C

i tried with the gauge you say but it wasnt possible, the cutting tip is too small for any of the cut aways, i took a chance and aligned it with a thread guage, wouldnt recomend it but it worked, i have just squared the tool holder with the workpiece and checked the cutting tip with the thread guage it aligns perfectly, lesson leaned.

Garry

[Author]

Posts