problem making threads

[rajsumanth9]

Hello Everyone,

I am currently working on creating a thread for a screw with a diameter of 0.15 inches. Could you advise on the optimal hole diameter for this screw size? Additionally, what would be the appropriate thread diameter to ensure a proper fit?

Thank you in advance for your assistance.

The following is the thread endmill that I am using.

Maximum Threads Per Inch 64
Minimum Threads Per Inch 40
Material Solid Carbide
Thread Type Internal; External
Thread Size #4-40 - #4-64
Shank Diameter (Inch) 3/16
Cutting Diameter (Decimal Inch) 0.0800
Overall Length (Decimal Inch) 2.0000

this is the thread mill link https://www.mscdirect.com/product/details/57568750?rItem=57568750

[a.laasW8M6T]

So do you already have a Screw that is .15" diameter and you want to thread mill a hole to suit?

Diameter alone is not enough info we would also need to know TPI as that dictates the minor diameter and pitch diameter offset values.

The question is why are you using a non standard thread?

.15" doesnt match any standard UN thread, if you are measuring with calipers on an existing bolt this seems closer to an M4 metric thread.

6-32 is 0.138"

8-32 is 0.164"

[damianvox]

Hi a.laasW8M6T,

I am collaborating with Raj, the original commenter, on the threading issue we previously discussed.

We did what you suggested and attempted using an 8-32 size, which corresponds to a diameter of 0.164 inches, and it appeared to be a step in the right direction – the screw seems to fit. However, we're encountering a new challenge: the threads are not engaging properly, preventing the screw from being fully inserted and secured.

We are utilizing M4 x 10mm Cup Point Set Screws. Considering the ongoing issue, we are beginning to suspect that the type of endmill we're using might be contributing to the problem. Here are the specifications of our current endmill:

• Maximum Threads Per Inch: 64
• Minimum Threads Per Inch: 40
• Material: Solid Carbide
• Thread Type: Internal & External
• Thread Size: #4-40 to #4-64
• Shank Diameter: 3/16 inch
• Cutting Diameter: 0.0800 inch
• Overall Length: 2.0000 inch

https://www.mscdirect.com/product/details/57568750?rItem=57568750

https://a360.co/47NXanQ 

I am eager to hear your thoughts on this. Could the endmill type be the root cause of the threading issue, or might there be another factor at play? Any insights or suggestions you could offer would be immensely valuable.

Thank you for your time and help.

Damian

[programming2C78B · Accepted solution]

.7mm/ 32tpi are all outside of the range of that tool. I doubt the flute is wide enough to get a full thread profile with it

[a.laasW8M6T]

Yes indeed, as above both of those threads cannot be cut by that thread mill.

Why not just tap it? taps are waaay cheaper than threadmills

[damianvox]

Thank you. This should fix the problem. 

[damianvox]

We did consider that. I have a CNC machine, and I want to do it with it. I do see your point, though. Thak you very much. 

[damianvox]

This is probably an obvious answer, but I am somewhat new to CNC and, specifically, threading. Would you say that this is the end mill I should have acquired in the first place for the threads in question?

Maximum Threads Per Inch 64
Minimum Threads Per Inch 32
Material Solid Carbide
Thread Type Internal; External
Thread Size #6-32 - #6-64
Shank Diameter (Inch) 3/16
Cutting Diameter (Decimal Inch) 0.0980
Overall Length (Decimal Inch) 2.0000

[a.laasW8M6T · Accepted solution]

Yes that could machine the 6-32 or the M4x0.7

You probably cannot tap in a Pocket NC mill I'm guessing?

[damianvox · Accepted solution]

Thank you for making my day! Unfortunately, I cannot tap it on this machine. You and the other gentleman have been incredibly helpful.

Please let me know if there is anything I can do for you guys.

Thank you so much.

[programming2C78B]

Damian I just got your message and have responded. Check your inbox here on the forums. 

[damianvox]

Hi, I do not see that option ( I am new here). However, I think the original commentator needs to do that. Maybe ? 

[programming2C78B · Accepted solution]