To Tap or to cut 1.25" x 7TPI internal threads?

[B2]

just weld a nut to the plate

Yes, but there is limited length of the threaded rod due to some other issues. My plan was to have nuts higher up that are used for a different purpose during the installation dealing ... with lifting the entire assembly to its final height. It, plus these others, holds a clamping plate that sticks out on both sides of the post to allowing one to lift the assembly using hydraulic jacks. Otherwise there is no place to push up from. After installation the lift place comes off and the nut could be run down a little to the threaded plate and tightened. So it would represent a lock nut to keep the rod from ever turning. When one has an assembly this long you better count on something being make with tolerances, or the measurement being off a little, or the house shifting positions changing the total distance a bit. So you need to have a little play during assembly of all of the tubes etc.

 

[projectnut]

Yeah, I don't understand equating the price of an Ebay tap to quality.

Are you kidding me? In most cases knowledgeable people selling on eBay know the retail prices of the items they sell and price accordingly

Those who sell no name products at lower prices primarily do so because they either don’t know the quality of the item, where it was made, or they recognize that the item isn't of the highest quality and won't command a premium price.

In this case the taps are made in the USA, but by a little-known manufacturer. That doesn't necessarily mean it's poor quality, but it's not widely recognized in the industry. You're always taking a chance buying on eBay, but there's less of a chance of failure when buying a well-known brand.

 

[RaisedByWolves]

Are you kidding me? In most cases knowledgeable people selling on eBay know the retail prices of the items they sell and price accordingly

Those who sell n

In this case the taps are made in the USA, but by a little-known manufacturer. That doesn't necessarily mean it's poor quality, but it's not widely recognized in the industry. You're always taking a chance buying on eBay, but there's less of a chance of failure when buying a well-known brand.

In what case?

The tap you linked to earlier?

 

[verbotenwhisky]

I would single point a thread this size.

 

[WobblyHand]

I would single point a thread this size.

Me too.

 

[GeneT45]

Me too.

Bin.Go! I do not understand all the sentiment about wasting dollars and time chasing this with a tap. I consider taps ( and dies ) an inferior, but convenient, alternative to single pointing a thread. If I'm going to single point something, I'll do it until it's done. No reason at all to run a tap through and make it a mediocre-at-best thread.

GsT

 

[WobblyHand]

Bin.Go! I do not understand all the sentiment about wasting dollars and time chasing this with a tap. I consider taps ( and dies ) an inferior, but convenient, alternative to single pointing a thread. If I'm going to single point something, I'll do it until it's done. No reason at all to run a tap through and make it a mediocre-at-best thread.

GsT

One is assured that a single pointed thread is cut true, if the part is properly placed in the chuck. (And you go straight in, or your compound is properly set.) Running a tap through, umm, might ruin your work, especially with a poor or hand held tap. A decent sharp tap and held on axis, (mechanically) no problem.

 

[epanzella]

For me...Single point....by a mile. The only way I would use a tap that big would be if I couldn't spin the part.