Set screw is both metric and SAE... What?

[67carl]

I finished assembling my bandsaw, even though most of the hardware is metric (but not all, so that is kinda screwy). I only have metric sockets, so for nuts/bolts I used crescent wrenches and vice grip locking pliers. But there are set screws that hold in the blade guard blocks. Those are hex head and I didn't have those wrenches in metric, so I used an SAE one that was close enough .

It worked getting them in, but now when I needed to adjust the screw the wrench is a bit loose. I didn't want to strip the hex opening on the screw so I stopped and went to HF to got some metric wrenches. But what I really want to do is replace those screws with a knurled set screw so I won't need a wrench. So I knew it took a 3mm hex wrench to remove it, but I needed to know what OD size of the screw. I found that number is either 5.91 mm, or 25/64 inch. Or would the screw size be determined by the size wrench I used to remove it (3mm). That seems unlikely. I'm going to take it to the hardware store and I'm sure will get it straight, but just thought I'd post here and see what you all think.

These are the screws







What I want to get

 

[CallumRD1]

That'll be M6x1mm.

 

[seber]

That'll be M6x1mm.

Or 1/4-20.

 

[RTM]

And they won't thread into the other's hole. So take it to the hardware store, and see where it fits. Or get a thread size checker, and do it at home.

 

[haveissues]

Sounds like it took a metric wrench to remove it so it should be a 6mm.

 

[CallumRD1]

Or 1/4-20.

A 1/4-20 wouldn't measure 5.9mm in diameter, it would be around 6.25mm. And you can measure the thread pitch to be sure. M6x1mm will have a 1mm thread pitch while 1/4-20 has a 20 TPI or 1.27mm thread pitch.

 

[JradM]

Hold the threads up against the replacement screw. If they are the same the threads will interlock.

 

[67carl]

I was able to verify it's M6 1mm. I want one that's threads are 8mm in length. Checking Amazon and wow, are they expensive. Average about $15 for one. I'll look at local hardware stores, but I don't need them that much!

 

[paulsomlo]

https://www.mcmaster.com/screws/head-type~thumb/

 

[RTM]

I was able to verify it's M6 1mm. I want one that's threads are 8mm in length. Checking Amazon and wow, are they expensive. Average about $15 for one. I'll look at local hardware stores, but I don't need them that much!

I will check my local hardware store for them tomorrow, typically $2 or so. $1 for postage to you. Might have to pick a different length tho, not sure they sell 8mm length.

 

[67carl]

I will check my local hardware store for them tomorrow, typically $2 or so. $1 for postage to you. Might have to pick a different length tho, not sure they sell 8mm length.

We have a pretty good neighborhood hardware store with several isles of hardware (nuts/bolts/screws/etc). Going to check there, but if do pick up a couple I'd be grateful!

 

[The Bean]

I rely on an aluminum thread checker. Available in both inch and metric.

 

[seber]

A 1/4-20 wouldn't measure 5.9mm in diameter, it would be around 6.25mm. And you can measure the thread pitch to be sure. M6x1mm will have a 1mm thread pitch while 1/4-20 has a 20 TPI or 1.27mm thread pitch.

Screws always measure less than the nominal dimension. Most 1/4-20 screws will measure around .239" or 6.0 mm.

 

[Blt2Lst]

Buy a set of metric allen wrenches and get on with life.

 

[jayemm]

Or if you really want to add to the confusion, go to Harbor Freight. A few years ago I got their assorted allen head SAE capscrew selection. Wondered why my SAE allen wrenches wouldn't fit on some sizes. Looking closer showed heads stamped 8.8. Yep, metric head and SAE threads. That **** went back.
Or maybe my experience with their roll pin assortment. Dimensions way out of spec. The 3/8" would actually fall through a 3/8" hole. They went back also. That's what I get for being cheap. Although more expensive, my local family owned hardware store who I've patronized for years has an amazing assortment of fasteners. No brainer. Sometimes we have to relearn our lessons.

 

[67carl]

I went to our local hardware and they had what I needed. Something like $0.65 each. Got the 8mm long ones because the old ones were that. Didn't realize that the old ones, without heads, screwed in below the surface of the guard. The knurled head on these, of course, stop them from doing that. No problem, I'll exchange them for longer ones. Makes it easier to adjust.

 

[cherrybomb]

Everyone should invest in thread checkers and a kit of thread chasers,your life and wrenching would be so much more enjoyable.Just my 0.06 cents

 

[67carl]

Everyone should invest in thread checkers and a kit of thread chasers,your life and wrenching would be so much more enjoyable.Just my 0.06 cents

The interesting thing is I do have a set (the one in the pic), but when I tried the hardware that is on the saw it only went in approx 2 threads then stopped. That's when I used the digital calipers. I'm going to look a little closer to see if the threads on the M6 checker are fouled.