Screw thread gauge?

yes, they do make thread gauges, they look like tiny saw blades

There is an app for screw pitch size for your smart phone.

Would it be safe to assume all Chinese made stuff is metric?

I use a gadget called the Screw Check'r. It's an aluminum plate drilled and tapped with various clearance holes, sizes and thread pitches. Test a screw by trying to screw it in; if it goes in easily it's the same as the marked hole; if it resists, it's something else. There are inch and metric versions. A great tool to have; you can get it from Amazon, from Brownell's gunsmith supply, and probably a lot of other places. 

Assume nothing. Most Chinese stuff is metric, but there are exceptions. There was a post the other day about some MTH tender screws that tested as inch, not metric, and I have some K-Line truck mounting screws that are 4-40. It is probably safe to assume that you won't find any BSW in the mix. 

I use one of these.  I have both the SAE and Metric versions.

 

Rich,

Any ACE Hardware store in your area?

They have the gauge in their "screw section".

Micro-Mark #10123. Drill bit and screw gauge. Page 30 in their summer tool a thon sale catalog. Sale $17.80

romiller

I have and use both styles of thread gauges. The "saw blade" type pictured above, and the "screw chek'r" type.

Sometimes there are threaded pieces made up in custom diameters, then you need to use the "saw blade" type.

You found the right source at Micro Fasteners for hobby related items

Mikey

I sent a sample screw to Micro Fasteners for my Lionel 213 tinplate center lift bridge and they matched it perfectly. Just tell them you want one 1/8" longer.

Mike

I can not find my Screw Checker, been looking for it for the past several days, so I could take a picture. Check some prices on line, about $15.00 to $21.00. At the bottom of my bucket list. 

Gary

• Cheers from The Detroit and Mackinac Railway

No, MTH does have a mix and at times some are US such as 4/40 and 6/32 despite having a metric length.  G

What Jim says. If you don't find a gauge just use a nut to verify thread size and pitch. 

 

Pete

MTH uses SAE screws for many locomotive and tender screws, but the trucks and other screws are metric.  I always found that curious.

I use this place quite a bit:

 

http://littlemachineshop.com/p...p?category=935142539

 

Great, fast service.

I have made a few boards with epoxied nuts and studs like the hardware store displays. I left them behind at various places with the folks that needed them more than I did. (I even threw in lefty threads painted red, as a reminder they exist.)

Every thread gauge I've bought has been "borrowed forever without permission"

 

Luckily I have a full line of taps.

 

Thanks of all your helpful input guys. This is one of the many reasons I love the OGR Forum and this great hobby!

 

- RICH

 

Yep, I also use that 'free service' once a week.

 

My local Fastenal is excellent.  

 

As Mikey said, Micro Fastners is one of the best sources.  They have all the really small stuff and I buy the value packs-many different sizes in one package.