How many thread starts in your lead screw?

[widgitmaster]

How many thread starts in your lead screw?

One start.
Two start.
Three start.
Four start.
Other.
Start what, I don't understand!

[jackson]

i guess idont either

[erase42]

i usually get about 4 starts before I need to charge the batteries

[ajl6549]

We're cutting up to a 17 start, 9.782" lead, worm gear (I know not exactly a "thread" but made like a thrd.). Must are 3 - 10 starts and 1.5" - 5" lead. They're very much the same as a std. acme thrd.

[jackson]

17 start i bet thats fun i do some three leads and they are pretty easy i know some machines have a setting for that mine do not so i have to make three different starts i would hate to have to do 17

[ajl6549]

Originally Posted by jackson 17 start i bet thats fun i do some three leads and they are pretty easy i know some machines have a setting for that mine do not so i have to make three different starts i would hate to have to do 17

We use MasterCAM and let it write it out long hand as opposed to a canned cycle. Also we have custom made tooling for the steep lead angles made for us by Iscar. Up till now we have been having this done out of house and it is very expensive and the company who seems to be the only place to get this done is very...undependable, i.e. they give a 4 week lead time and then after the four weeks they say "maybe it'll be another 4 who knows". Totaly unexceptable! But they had us over a barrel so to speek.

[jackson]

Originally Posted by ajl6549 We use MasterCAM and let it write it out long hand as opposed to a canned cycle. Also we have custom made tooling for the steep lead angles made for us by Iscar. Up till now we have been having this done out of house and it is very expensive and the company who seems to be the only place to get this done is very...undependable, i.e. they give a 4 week lead time and then after the four weeks they say "maybe it'll be another 4 who knows". Totaly unexceptable! But they had us over a barrel so to speek.

yeah thats always the way it goes if they think they got you, i have my inserts made here localy and they do a good job, do you have any idea what iscar charges, and i do wright mine in a canned cycle but like i said i only have to do a 3 start so it only took a min.

[ajl6549]

They'er about $50.00 ea. and we use a special holder to place the tool on the correct angle to match the lead angle.

[jackson]

Originally Posted by ajl6549 They'er about $50.00 ea. and we use a special holder to place the tool on the correct angle to match the lead angle.

Oh ok see all i do is have the insersts ground for the angle $110. for 10 inserts but you having 17 lead not sure if that would work for you.

[ajl6549]

Well it's not so much the number of starts as it is the helix angle(lead angle). The helix angle is greater with higher pitch rates. The helix angle for the 17 start one I described above is 45 deg. but most are between 6 and 20.6 deg. Small helix angles may be made with "standard like" acme thread inserts provided the thread angle, tooth thickness and whole depth can be achieved.

[jackson]

right that is what i have them ground for, and the ones i do are no bigger than 3/8, and i would just have to se what your running to fully grasp it probably

[ajl6549]

On most of the inserts the whole tool holder is turned/tilted. Think of your holder in a 4 -way lathe tool post except its milled on an angle so it leans to the left for a right hand thread, the same way the threads "lean".