Finding the correct screw for threaded inserts

[vertexguy]

Can someone help me understand how to find the right sized screw to fit threaded inserts?

I picked up a few 8-32 inserts for under mounting my joysticks on my CP.  Trouble is I have no idea what 8-32 even means and my first guess at a screw to fit it just proved to be incorrect.  I assume Lowe's will have the screws I need somewhere?  Can anyone point me to the right type?

[bperkins01]

its an 8-32 machine screw.

#8 is the screw size, 32 threads per inch..  its really that simple.
https://www.amazon.com/8-32-Knob-Pull-Machine-Screws/dp/B001ENXIC4/ref=sr_1_2?dchild=1&qid=1595204796&refinements=p_n_feature_fourteen_browse-bin%3A11433961011&s=industrial&sr=1-2

as an example

Whats the issue?

[PL1]

The other concern with choosing screws for threaded inserts is the length of the screw.
- The ones linked above are #8-32 x 1-1/2".
- The screws that come with the GGG threaded inserts are 10-32 x 0.6"

If you get screws that are too long, they will either bottom out before they hold the joystick mounting plate securely or, worst case scenario, when you tighten them they will push up/through the top surface of the CP.   



Measure the thickness of the joystick mounting plate plus the depth of pilot hole you'll drill for the threaded inserts to determine the maximum length screw.

For example:
- GGG threaded inserts are 0.4" deep, so the minimum pilot hole depth is slightly over 0.4"

- A Happ joystick mounting plate is 0.25" deep so the 0.6" screws will work perfectly with the minimum pilot hole depth.
(0.6" screw length - 0.25" plate = 0.35" ==> 0.4" pilot hole is good)

- A metal mounting plate is only about 0.065" deep, so the 0.6" screws will need a slightly deeper pilot hole.
(0.6" screw length - 0.065" plate = 0.535" ==> minimum 0.535" pilot hole)


Scott

[vertexguy]

Thanks guys.

I knew the #8 part but since it was near all the metric stuff I wasnt sure if it was M8 or #8. 

 Scott you hit the part of my question that wasnt clearly stated.  I'm using flat 1/16 thick metal faceplates that came with all the joysticks to add to the depth.  I'm nervous about drilling those holes at precise depth and now thanks to your oops pic, I have to worry about overdoing the screw lengths.   I was hoping a 3/8 screw lengrh would be enough.

Heres what throws me though.  The Hillman pack of metal machine screws I picked is #8 x 3/8 in.  However NO WHERE on the package does it say thread count.  When I got home it wouldn't thread proper into the inserts. I also noted these have point ends.  So how do I match the thread count if theres no indicators?

 

[PL1]

I'm using flat 1/16 thick metal faceplates that came with all the joysticks to add to the depth.  I'm nervous about drilling those holes at precise depth and now thanks to your oops pic, I have to worry about overdoing the screw lengths.   I was hoping a 3/8 screw lengrh would be enough.

I used the wrong screw and a slightly too-shallow pilot hole on that thin piece of MDF shelf.   

If you're worried about drilling too deep, get a set of drill bit stop collars like these.

Just a few questions to be clear:

-  How thick is your CP?

-  How deep are your threaded inserts?

-  Are you routing a pocket so the joystick sits higher?
If so, consider using the "Under mount (support blocks)" method here in the wiki.

The Hillman pack of metal machine screws I picked is #8 x 3/8 in.  However NO WHERE on the package does it say thread count.  When I got home it wouldn't thread proper into the inserts. I also noted these have point ends.

Pointed end screws are sheet metal screws or wood screws -- neither will work with threaded inserts for machine screws.

Look for the big signs above where the screw packages are hanging.      

So how do I match the thread count if theres no indicators?

If the thread count isn't shown on the package, it should be marked as either "coarse"/"UNC"/"UNRC" (8-32) or "fine"/"UNF"/"UNRF". (8-36)

National Fine Thread Sizes (UNF/UNRF) - https://www.eaglefastener.net/technical/fine-thread.html

National Coarse Thread Sizes (UNC/UNRC) - https://www.eaglefastener.net/technical/couse-thread.html


Scott

[vertexguy]

If you're worried about drilling too deep, get a set of drill bit stop collars like these.

Yep, good thinking.  I only recently learned about these handy things.  I'm conjuring up a poor mans way of using 2 with some card board in between for a cheap but hopefully effective forstner bit stop.

Just a few questions to be clear:

-  How thick is your CP?

-  How deep are your threaded inserts?

-  Are you routing a pocket so the joystick sits higher?
If so, consider using the "Under mount (support blocks)" method here in the wiki.

3/4 inch ply and mdf for test panels.

Yes I'm raising the sticks underneath a bit (approx 1/4) but can't go too high or I won't have room for the lighting. (see my build thread for more details).  Supporting blocks / metal braces underneath to sandwich it in is a possibility too provided there's room.  I may have to use some sort of solution like this for my custom spinner mount to work with lighting.

Inserts from Lowe's are 7/16 deep.  T Nuts are slightly less with a 5/16 shaft and 1/32 lip as an option too but it didn't seem like they would grab quite as well?

Pointed end screws are sheet metal screws or wood screws -- neither will work with threaded inserts for machine screws.

Look for the big signs above where the screw packages are hanging.      

Yes but as someone new, I would have no way of knowing a threaded insert requires a particular type of screw.  There's a ton of assumed knowledge with all things in a hardware store.   My logic was that I'm going into a metal threaded insert so I need a metal screw. 

If the thread count isn't shown on the package, it should be marked as either "coarse"/"UNC"/"UNRC" (8-32) or "fine"/"UNF"/"UNRF". (8-36)

That would have helped, but no such markings exist.

See the images attached.  The world is full of UX problems...

[JDFan]

Yes but as someone new, I would have no way of knowing a threaded insert requires a particular type of screw.  There's a ton of assumed knowledge with all things in a hardware store.   My logic was that I'm going into a metal threaded insert so I need a metal screw. 

And that is why there are employees working in the area ! If you are not sure what you need just ask one of them and they should be able to tell you what you need. ( or at least find another employee there that does know )

[bperkins01]

I have to admit - this is a bit of a baffling thread.
Why not take the threaded insert to the store with you and test the screws?

I'd recommend going to a local hardware store (Ace for example) vs. Home Depot since they sell screws from open assortments and you can test fit them and they will have a human that can help..

That said - screw types - unlimited number of them.. and even if you JUST used #8 machine screws - there are are a number of screw heads on them (flat, oval, round, hex,.....)

https://www.google.com/search?sxsrf=ALeKk035bk7GIwmysiEcvdC7ulFqo0SNVQ:1595362854943&source=univ&tbm=isch&q=screw+types&sa=X&ved=2ahUKEwjbvIbild_qAhWMVs0KHQ3TBt4QjJkEegQIChAB&biw=1631&bih=808#imgrc=bCj4cI1H3AnEFM

 

[vertexguy]

I'd recommend going to a local hardware store (Ace for example) vs. Home Depot since they sell screws from open assortments and you can test fit them and they will have a human that can help..

Plus one on Ace.  Just wish it was closer to me.  They definitely tend to have more knowledgeable people and I agree I like being able to mess with open stuff to solve problems.  With Covid it's even harder to find help these days.   

[PL1]

I'm conjuring up a poor mans way of using 2 with some card board in between for a cheap but hopefully effective forstner bit stop.

Cardboard is too flimsy, but you could use a hole saw cutout like this.
- You will need to drill out the center of the cutout.
- If you don't have a holesaw, drill the center hole for the cutout and cut the body with a jigsaw.
- Leave a path for the chips to escape.

3/4 inch ply and mdf for test panels.

Yes I'm raising the sticks underneath a bit (approx 1/4) but can't go too high or I won't have room for the lighting. (see my build thread for more details).  Supporting blocks / metal braces underneath to sandwich it in is a possibility too provided there's room.  I may have to use some sort of solution like this for my custom spinner mount to work with lighting.

Inserts from Lowe's are 7/16 deep.

The "Under mount (threaded inserts)" method in a 1/4" pocket is cutting it way too close.   

You'll definitely want to use some variation of the "Under mount (support blocks)" method with the threaded inserts installed in a full-thickness area of the CP outside the pocket area.

T Nuts are slightly less with a 5/16 shaft and 1/32 lip as an option too but it didn't seem like they would grab quite as well?

T-nuts go on the side of the board opposite the screw.
- The T-nuts are on top in the blue recess, screws on the bottom.
- The flange on the T-nut keeps it from pulling through the board when you tighten the screw.
- The prongs or brads keep the T-nut from rotating, not from pulling out.

I would have no way of knowing a threaded insert requires a particular type of screw.  There's a ton of assumed knowledge with all things in a hardware store.

Sorry, thought you would bring the insert to the store to confirm you had the right screws.   

Now you know, and knowing is half the battle.   

If the thread count isn't shown on the package, it should be marked as either "coarse"/"UNC"/"UNRC" (8-32) or "fine"/"UNF"/"UNRF". (8-36)

That would have helped, but no such markings exist.

The "metal" marking on the package is short for "sheet metal."

Markings like "brass", "stainless", or "zinc" refer to the type of metal the screw is made from.


Scott