Grub screws

[Pi Curio]

Building a DIY battery made out of EVE LF105 Ah cells and am wondering if anyone has used grub screws for cell terminal posts before.

Got few questions;

Which grub screws did you use, what material?

Are there any concerns about using stainless steel grub screws for an aluminium battery cell terminal?

Does anyone happen to know where I could buy M4 titanium grub screws?


Thanks.

 

[Culchee]

Building a DIY battery made out of EVE LF105 Ah cells and am wondering if anyone has used grub screws for cell terminal posts before.

Got few questions;

Which grub screws did you use, what material?

Are there any concerns about using stainless steel grub screws for an aluminium battery cell terminal?

Does anyone happen to know where I could buy M4 titanium grub screws?


Thanks.

Seems they sell titanium grub screws on eBay... they are popular in the diy model racing world.. I wonder how good at conducting titanium is..?

 

[Culchee]

Building a DIY battery made out of EVE LF105 Ah cells and am wondering if anyone has used grub screws for cell terminal posts before.

Got few questions;

Which grub screws did you use, what material?

Are there any concerns about using stainless steel grub screws for an aluminium battery cell terminal?

Does anyone happen to know where I could buy M4 titanium grub screws?


Thanks.

Here’s some in Europe

Hexagon socket set Titanium screws with cup point DIN 916 - TA6V (grade 5) - Diameter M4 - TITANE SERVICES

www.titane-services.eu

 

[Steve_S]

Grub Screws were pretty common a while back. Most used Stainless, and some used Brass... Stainless is better obviously... Do not use steel or galvanised eh ! Note that the tapped holes are usually 5mm deep, DO NOT BOTTOM the screws, you could punch through and kill the cell. Grub Screws with a small fallen hole to hold it while tightening the nut is best. A Serrated Washer or Lock Washer is strongly suggested between the busbar & nut.

 

[Pi Curio]

Seems they sell titanium grub screws on eBay... they are popular in the diy model racing world.. I wonder how good at conducting titanium is..?

Titanium, although significantly more compatible with aluminium alloys than stainless steel, is a poor conductor but that shouldn't matter in this case.

The actual electrical connection would be made between the cell terminal and the tin plated copper busbar via compression.

Probably a silly question about Ebay. I hadn't made purchases there for many years, now it seems PayPal isn't the method there anymore. Tried to make an order via PayPal recently but it didn't go through.

My question is, how safe is it to make purchases on ebay with card, any recommendations on that front?

Appreciated.

Here’s some in Europe

Hexagon socket set Titanium screws with cup point DIN 916 - TA6V (grade 5) - Diameter M4 - TITANE SERVICES

www.titane-services.eu

Yeah, that one looks to be the most legit one I've found too. IIRC, I'll have to wait till the holidays are over and contact them about MOQ etc.

 

[Culchee]

Titanium, although significantly more compatible with aluminium alloys than stainless steel, is a poor conductor but that shouldn't matter in this case.

The actual electrical connection would be made between the cell terminal and the tinned copper busbar via compression.

Probably a silly question about Ebay. I hadn't made purchases there for many years, now it seems PayPal isn't the method there anymore. Tried to make an order via PayPal recently but it didn't go through.

My question is, how safe is it to make purchases on ebay with card, any recommendations on that front?

Appreciated.

Should be ok with credit card.. log in to your PayPal account ... maybe something needs updating... I think most eBay purchases have some sort of protection.. whether a seller is able to see all your credit card details when you make a purchase, I doubt it..unless you end up phoning in the order for some reason... if you’re worried... use a debit card with limited access to funds... or a disposable card that some online banks offer..

 

[Pi Curio]

Should be ok with credit card.. log in to your PayPal account ... maybe something needs updating... I think most eBay purchases have some sort of protection.. whether a seller is able to see all your credit card details when you make a purchase, I doubt it..unless you end up phoning in the order for some reason... if you’re worried... use a debit card with limited access to funds... or a disposable card that some online banks offer..

Makes sense, Thanks.

 

[Steve_S]

When it comes to very specific things like grub screws etc, you are Far better off going with a proper electronics supply house like DIGI-Key or similar... With Ebay/Amazon the vendors can be problematic, especially for such... Many have BTDT and regretted it.
IE Brass Tin Plated busbars are CRAP but super cheap but they don't tell you other than it's a "BusBar". Plated Copper is more $ but the proper solution.

Also... the screw is NOT to be considered for conducting power... the Pad & Busbar are the conducting surfaces.
Make sure there are No Ridges or burrs on the busbars either, they need to be perfectly smooth.

 

[Culchee]

When it comes to very specific things like grub screws etc, you are Far better off going with a proper electronics supply house like DIGI-Key or similar... With Ebay/Amazon the vendors can be problematic, especially for such... Many have BTDT and regretted it.
IE Brass Tin Plated busbars are CRAP but super cheap but they don't tell you other than it's a "BusBar". Plated Copper is more $ but the proper solution.

Also... the screw is NOT to be considered for conducting power... the Pad & Busbar are the conducting surfaces.
Make sure there are No Ridges or burrs on the busbars either, they need to be perfectly smooth.

I was wondering about the posts/screws... because they go into the terminal and therefore must also conduct electricity.. but not considered for conducting power...?

 

[Steve_S]

I was wondering about the posts/screws... because they go into the terminal and therefore must also conduct electricity.. but not considered for conducting power...?

No, screws should not be considered as an energy conductor, even though it does. Therefore the proper material is important. The "contact pads" are what are considered for "energy transfer" purposes.

 

[Culchee]

No, screws should not be considered as an energy conductor, even though it does. Therefore the proper material is important. The "contact pads" are what are considered for "energy transfer" purposes.

Thanks Steve..

 

[Pi Curio]

When it comes to very specific things like grub screws etc, you are Far better off going with a proper electronics supply house like DIGI-Key or similar... With Ebay/Amazon the vendors can be problematic, especially for such... Many have BTDT and regretted it.
IE Brass Tin Plated busbars are CRAP but super cheap but they don't tell you other than it's a "BusBar". Plated Copper is more $ but the proper solution.

Also... the screw is NOT to be considered for conducting power... the Pad & Busbar are the conducting surfaces.
Make sure there are No Ridges or burrs on the busbars either, they need to be perfectly smooth.

I've just checked the Digi-Key, there are no grub screws but there's an M4x10mm Cheese Head Hex Drive bolt, roughly good for about 5.85Nm.

Bit expensive, would need to order 50 pieces to get free shipping, in total 130$. However, If I order only 25 pieces then the shipping applies and the total is roughly 106$ hence the reason for 50 minimum.

Though, I agree that this is probably one of the more legit places to get titanium hardware. Will check the site a bit more and see if there are some other options for making the order.

Thanks.

 

[Steve_S]

Digi-key is a bit pricey retail but McMaster Carr and others can be pretty reasonable, you have to shop around a bit. I deal with Canadian Resources for that kind of stuff so I can't offer links to other US suppliers. Surprised your vendor did no supply screws, busbars etc... I though that everyone did these days.

 

[Pi Curio]

Digi-key is a bit pricey retail but McMaster Carr and others can be pretty reasonable, you have to shop around a bit. I deal with Canadian Resources for that kind of stuff so I can't offer links to other US suppliers. Surprised your vendor did no supply screws, busbars etc... I though that everyone did these days.

I did receive the screws, washers, and the busbars with my battery cells order. Just looking into options with grub screws from titanium material.

If I would use supplied stainless steel hardware, no markings, at best most likely A2 one, is there any risk for a reaction between the aluminium pads and the screw down the road?

New to this so it's possible I'm overthinking it. I've seen a lot of builds with supplied stainless steel hardware.

Thanks.

 

[Steve_S]

yes, over thinking it... Those screws & busbars will be perfectly fine.
Just make sure no burrs or ridges on the busbars (holes) and that you clean the surfaces with rubbing alcohol before assembly. Some folks will use a very small dab of No-A-Lox (a very very thin coat only, No Gobs) between the busbar & pad IF they are in a humid environment.

Download this guide I wrote a couple of years ago... a lot of questions are answered in it...
Luyuan Tech Basic Lifepo4 Guide V1.0A
This will also be handy for you and also grab the Update attached to the resource
General LiFePO4 (LFP) Voltage to SOC charts/tables 12/24/48V

 

[Pi Curio]

yes, over thinking it... Those screws & busbars will be perfectly fine.
Just make sure no burrs or ridges on the busbars (holes) and that you clean the surfaces with rubbing alcohol before assembly. Some folks will use a very small dab of No-A-Lox (a very very thin coat only, No Gobs) between the busbar & pad IF they are in a humid environment.

Thanks for the tips, I'll do just that.

Download this guide I wrote a couple of years ago... a lot of questions are answered in it...
Luyuan Tech Basic Lifepo4 Guide V1.0A
This will also be handy for you and also grab the Update attached to the resource
General LiFePO4 (LFP) Voltage to SOC charts/tables 12/24/48V

Awesome! Thanks for taking the time, much obliged.

 

[DougfromdaUP]

Try searching for "socket screw" and "socket set screw."

In my area, a grub screw is a set screw that is short enough to be driven all the way into the hole.

Many set screws give up a couple of threads to make the point that digs into the shaft. This may be a problem if you can't get enough engagement with the aluminum. I wonder why you want that?

I'd be way more concerned with getting the right material than the head style.