Help identify and locate suitable parts?

jw11432 · Aug 17, 2020

I'm no fabricator or machinist, this is just something I find myself needing to create for a project I must complete. Please reference picture below. The metal rod in the picture has what I can only describe as very largely gapped machine threads. That black plastic piece threads into a tubular housing (with the finer threads at the top) but the large threads from that rod are what go inside that black plastic piece to move it up and down.

What I need help with is identifying (if even but roughly) what "thread" this is and where I might locate a metal "nut" that I can use as a basis for some fabrication I'm planning on undertaking. Many thanks in advance!

EDIT: I should have mentioned, I have already ordered a thread/pitch gauge to accurately measure what size threads this thing is to be sure I am able to order what I need. I just don't even know where to start searching for this, I'm assuming there are some industry specific terms I'm unaware of that would greatly help my search.

dalmatiangirl61 · Aug 17, 2020

That is either a Brown & Sharpe thread or a modified Acme thread, I think, hard to tell with a pic.

What is this piece from? If its standard consumer grade, it might/probably will be cheaper to replace than repair. Wild guess, gate opener?

jw11432 · Aug 17, 2020

So when you say modified, do you mean a modified thread? Or the rod itself is a simple ACME threaded rod that has been modified with the addition of the smooth shank on top? If you think it may be a modified thread, I'm curious as to how you could possibly discern that as well as what that means exactly? Strictly a curiosity, I don't want that question to come across as a challenge lol

It is from a generic linear actuator. I have incorporated it to be used with a driveway swing gate setup I designed, but the weak point is its use of a thin walled aluminum tube housing which breaks fairly easily, so I'm "upgrading" it to a steel tube and I need to accommodate for this critical component in the actuators design.

dalmatiangirl61 · Aug 17, 2020

An Acme thread is square, in your pics it appears the threads have a taper, so it is either a "modified Acme thread" this is a specific profile, or it is a Browne & Sharpe thread. Specs can be found in Machinery Handbook. McMaster Carr has Acme nuts, not sure if they have the modified or Browne & Sharp. Quite honestly, unless you have a machine shop, the odds of fixing that cost effectively are slim.

jw11432 · Aug 17, 2020

Ah I see, thank you, that is helpful. Yes, they do appear to have a slight taper. I was thinking of taking this piece to a huge fastener outlet and see if I can't find a matching nut for it. If it is modified to the point of being unable to find an off-the-shelf nut, then I think my next course of action would be to replace this rod with an off-the-shelf, but as close as possible to same size, ACME threaded rod and accompanying nut. With enough length, I think I can grind down one end to achieve my smooth shank, but I would of course need to rig a lathe setup and I've since ordered a digital caliper for getting this measurement right. Thank you for your input, it saved me much time I'm sure.

awander · Aug 17, 2020

dalmatiangirl61 said:
An Acme thread is square...

Since when?

dalmatiangirl61 · Aug 17, 2020

awander said:
Since when?

Its been 40 years since I cut an Acme, so if I got any of that info wrong feel free to correct. Maybe its square thread, Acme, B&S? I would need to go dig out my Machinery Handbook.

jw11432 · Aug 18, 2020

Thanks for your input awander, I just googled it and found that acme threads appear to in fact not be square. There are apparently some differentations, such as trapezoidal. This form has a 30° angle, whereas acme has a 29° angle. Minute but likely important difference for longevity. I hope my pitch gauge is capable of identifying, but I'm thinking it won't. I'm sure the right store will be able to help identify my specific item.
Acme vs. Trapezoidal Threads - What's the Difference? - North American Tool | A GWS Tool Group Company

dalmatiangirl61 · Aug 18, 2020

Yeah, that is why I referred you to machinery handbook, because I was not going to quote angles. I'll dig mine out for a refresher, the good news is that I now know what day I started losing my marbles and jumbling information

1953chevB · Aug 18, 2020

jw11432 said:
I'm no fabricator or machinist, this is just something I find myself needing to create for a project I must complete. Please reference picture below. The metal rod in the picture has what I can only describe as very largely gapped machine threads. That black plastic piece threads into a tubular housing (with the finer threads at the top) but the large threads from that rod are what go inside that black plastic piece to move it up and down.

What I need help with is identifying (if even but roughly) what "thread" this is and where I might locate a metal "nut" that I can use as a basis for some fabrication I'm planning on undertaking. Many thanks in advance!

EDIT: I should have mentioned, I have already ordered a thread/pitch gauge to accurately measure what size threads this thing is to be sure I am able to order what I need. I just don't even know where to start searching for this, I'm assuming there are some industry specific terms I'm unaware of that would greatly help my search.

View attachment 296953

do you have any calipers which you can measure the O.D.?
use a ruler and measure the number of threads in one inch (TPI)

from the previous post try to match up to acme thread.
do you have a machinist hand book? if not post up what you measured.

kustomizer · Aug 18, 2020

dalmatiangirl61 said:
Yeah, that is why I referred you to machinery handbook, because I was not going to quote angles. I'll dig mine out for a refresher, the good news is that I now know what day I started losing my marbles and jumbling information

Marbles are not always lost but absorb alcohol, become kinda squishy then don't roll around as they should. The one you want to roll up this afternoon will likely surface about 2am when no one wants to hear about it.

kustomizer · Aug 18, 2020

dalmatiangirl61 said:
Yeah, that is why I referred you to machinery handbook, because I was not going to quote angles. I'll dig mine out for a refresher, the good news is that I now know what day I started losing my marbles and jumbling information

Marbles are not always lost but absorb alcohol, become kinda squishy then don't roll around as they should. The one you want to roll up this afternoon will likely surface about 2am when no one wants to hear about it.

As an example, I have no idea how I got 2 of this post.

jw11432 · Aug 18, 2020

1953chevB said:
do you have any calipers which you can measure the O.D.?
use a ruler and measure the number of threads in one inch (TPI)

from the previous post try to match up to acme thread.
do you have a machinist hand book? if not post up what you measured.

Just got it in the mail today, actually!

So if I did this correctly (pic for reference) I'm seeing 1/2" OD (color me shocked, I was expecting metric since it's chinese made) and 8 TPI.

dalmatiangirl61 · Aug 18, 2020

McMaster Carr item# 94815A107 , that is a hex nut 1/2" 8tpi, seems most of what they have in 1/2" is 10tpi

jw11432 · Aug 18, 2020

Looks like you grabbed the one just below that lol

McMaster-Carr is the 8tpi

But thanks for getting me to the page!

1953chevB · Aug 18, 2020

jw11432 said:
Looks like you grabbed the one just below that lol

McMaster-Carr is the 8tpi

But thanks for getting me to the page!

good ol McMaster Carr they have every thing , 1/2-10 ACME is the common one, 1/2-8 is listed ANSI ASME B1.5
Good luck with your project
Stay Safe

jw11432 · Aug 18, 2020

I suppose my next question is how to determine the size and thread of the finer-threaded piece on that plastic end. My new thread gauge shows the threads to be "1.5" and the diameter is .70" or 17.8mm (measuring crest of threads, not in valleys)...because if I can find a left-hand tap, then that would be much easier to do than fabricating a whole new piece lol

1953chevB · Aug 18, 2020

jw11432 said:
I suppose my next question is how to determine the size and thread of the finer-threaded piece on that plastic end. My new thread gauge shows the threads to be "1.5" and the diameter is .70" or 17.8mm (measuring crest of threads, not in valleys)...because if I can find a left-hand tap, then that would be much easier to do than fabricating a whole new piece lol

closes to that is MF18 1.5 metric

jw11432 · Aug 18, 2020

The measurement just seems off though. Should I be measuring in the valleys (or gaps between threads)? I want to say I recall reading that's the nominal diameter, which is often used for referencing the diameter. When I measure that way, I do get a pretty clean 17mm measurement. What are your thoughts on this? My thinking is that the most "normal" measurement would be the one that I ought to be using. I did manage to find a M17-1.5 reverse thread tap on amazon. However, now I'm wondering what the "F" is for in your suggestion, I've never seen metric sizes use an "F" before?

awander · Aug 18, 2020

The nominal diameter of a thread is the outside diameter (or very close to it).

You should be measuring the OD, not "in the valleys"

You might be thinking of the Pitch Diameter, which is about midway between the crests and the valleys, but that measurement is used when you are making or testing a thread to see if it is in tolerance.

The black plastic thread looks to be a standard metric or Unified thread; that is, it doesn't appear to be an Acme thread. it looks like the the threads are standard 60 degree "triangles". Can't really tell from the photo...

For deciding what size a thread is, the OD is the measurement that will be closest to the nominal diameter.

Help identify and locate suitable parts?

Plastic

Diamond

Plastic

Diamond

Plastic

Stainless

Diamond

Plastic

Diamond

Cast Iron

Diamond

Diamond

Plastic

Diamond

Plastic

Cast Iron

Plastic

Cast Iron

Plastic

Stainless

Similar threads