A thread about threads

[david brum]

I'm trying to sqeeze a bit more utility out of my Jet JWS 22 shaper. This is a little guy, but fits my need just fine. My major complaint is that the spindle only retracts under the table about 1/2". This means that many cuts require a sub table in order to lift the work enough to match the cutter's profile. That gets old really quickly, although it works.

I had the bright idea of removing the cast iron table and manufacturing some spacers to lift the table up another 1/2" or so. This requires the spindle cartridge housing to be unbolted from underneath the table, a spacer and longer bolt added, and voila' more capacity.

I got the table off, removed the bolts, and headed down to the hardware store for longer ones. I returned to find that the new bolts (1/2") didn't match the thread pattern of the old ones. The diameter is the same, definitely not metric. They were 12tpi instead of 13tpi, which is the US standard (UNC). A bit of research revealed that these are Whitworth (BSW) thead bolts, once a common size in the UK, but now obsolete. Huh? On a 5 year old Taiwanese shaper? Especially strange, since all of the other fittings are standard thread.

A bit more research revealed that many Taiwanese machines use Whitworth thread 1/2" 12 bolts. More research reveals there there is one (1) place on the web in the US to buy Whitworth thread bolts. They are between $3-7 each, not counting shipping from NY. Bolts shipped from the UK start around $7 each, not counting shipping. Ouch.

Anybody else encountered this?

[Phil Thien]

Wow, that is quite surprising.

Hope you don't need too many of the things. I think your mod is still worth doing.

[david brum]

Thanks, Phil. I only need three. It's just surprising that two bucks worth of bolts is now twenty bucks!

[Jay Rasmussen]

I’ve done this before. Not on a shaper but the same situation.

Cut the thread plus a little unthreaded portion if you have it from the current bolt. Get a standard ½ bolt and cut the tread off. Drill/tap for 5/16 or 3/8 in both parts, use set screws or threaded rod to join it together for the correct length. A little work but cheep.

Jay

[Peter Kelly]

I think some of the early shapers by Jet were knock-offs of the Wadkin Tradesman hence the Whitworth thread pitch.

[david brum]

Cut the thread plus a little unthreaded portion if you have it from the current bolt. Get a standard ½ bolt and cut the tread off. Drill/tap for 5/16 or 3/8 in both parts, use set screws or threaded rod to join it together for the correct length. A little work but cheep.

Thanks Jay. That's a pretty good trick. This is a high stress situation, so I would prefer to use full thickness bolts if I can find them. I still might still drill and tap everything for 9/16 or similar if I can't get them.

[david brum]

I think some of the early shapers by Jet were knock-offs of the Wadkin Tradesman hence the Whitworth thread pitch.

Oy Vay. I wonder if a lot of tooling is still that size and it's used where nobody is likely to see it.

[Mark Wooden]

That's the problem with the Chinese knock off's- they reproduce everything, sometimes even the mistakes.
But in your case, it's probably leftover from when Taiwan was being govered by the British.
I'd change them out to 9/16", take less time and dough than trying to find the Whitworth bolts

[Peter Kelly]

You're thinking of Hong Kong. Taiwan was ruled by Japan until the end of WW II.

[Thomas Hotchkin]

David
You might want to go metric, unless you already have the 9/16" tap. I have not checked metric sizes but should be one right between 1/2" and 9/16", and you will save a little metal not having to go 1/16 oversize. Tom

[david brum]

I'd change them out to 9/16", take less time and dough than trying to find the Whitworth bolts


You might want to go metric, unless you already have the 9/16" tap. I have not checked metric sizes but should be one right between 1/2" and 9/16", and you will save a little metal not having to go 1/16 oversize. Tom

Thanks, Mark and Thomas. It looks like I can get the bolts from British Tools and Fasteners (http://www.britishfasteners.com/index.php/categories/steel-bsw-bolts)in NY, although they're 5 bucks each. As long as I can actually get them, that's the easiest, safest route. If I can't, it looks like I'll be drilling and tapping some cast iron.

[Mark Wooden]

You're thinking of Hong Kong. Taiwan was ruled by Japan until the end of WW II.

Oops. You're right ,I am. Never have been good at history beyond trying to not repeat it.
David, glad you were able to find the bolts.

[Carl Beckett]

I had some old British cars for a while. Plenty of Whitworth threads and in/around the engine block were the hardest to deal with.

Just drilling and retapping is my advice. Not worth the hassle of always having to chase them down. Cast iron isnt all that hard to tap.

[Jeff Duncan]

I'd say if you have the tap already then tapping may be the most cost effective solution. Of course if you don't have a 9/16" tap handy, $5 a piece is will get er' done!

good luck,
JeffD

[Rick Potter]

David,

That is a problem I would never anticipate. Great idea on lifting the table though, gonna memory bank that one.

Rick Potter

[david brum]

Thanks for the encouragement, guys. I got an email back from British Fastener. They actually have some allen head bolts in the size I need. That will work fine, although I'm anxious about what size allen wrench is required :eek:. Anyway, the total price with shipping was $10.75, so not as bad as feared (but still a lot for three bolts).

After everything is hooked up, I'll do a little review of how it worked.

[Dick Brown]

If you don't want to drill and tap, and you have an arc welder or a torch setup, cut the head off your bolt, cut a 1/2" bolt the length you need to make up what you want, point both cut ends so you can get a good weld, lay them in an angle iron with the head over the end so they are lined up, clamp, weld, grind off any lumps and you are good to go.