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Left Hand Thread on HLV-H

Not done it myself but the stops would still work unlike running with the spindle in reverse. You would need a groove to start in, I bet other members have done it and will have more practical advice.
 
Left hand thread is as easy to cut as rht on an hlv-h , cut many myself.

Do not reverse spindle . just cut in forward away from the chuck . The threading stops work on the other side on the carriage and are just as accurate as the rht stops.

Use the left side stop to limit return position, so you don't reverse into the chuck.
 
Got a bunch of shafts to cut a 9 tpi left hand thread on... big shafts for a HLV, but I was thinking I’d give it a try just to see how it went. I’ve done a fair bit of RH threading on the machine now, and it’s a joy... Anyway, so my specific question is, are you doing a straight plunge on the LH thread on the HLV? The compound won’t swing over to get the
equivalent of the 29-1/2 degrees...

I’ve threaded a bazillion of these shafts on the Whacheon, and starting at the shoulder and cutting toward the live center is easy peasy..... but I still want to try the HLV. :)

(Actually it’s a English/Metric Feeler FWIW)
 
A bar for a right-hand thread can be cut easily going from right to left.

The same bar for a left-hand thread can be easily cut. The cutting bit is turned upside down and the speed selector is in reverse.
The only physical thing that is altered is the tool holder height. The direction lever is used in reverse fashion.

Sounds easy because it is. For other situations you have to think in reverse.:scratchchin:
 
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You may thread left to right in forward rotation. If you use reverse, **you cannot use the threading stops**.

I just tried it and you are right. In reverse nothing stops the carriage. My error. :bowdown:

If the left stop is secure and the carriage runs into it, the carriage keeps moving and the left-right lever does not move.
The only way to stop the carriage is stop is by the speed lever. Quite dangerous as the motor spins down and the carriage keeps moving.

I did do left-hand threading as I described. I thought the job involved threading up to a shoulder as is usual for right-hand stuff.
I only did this once but it must have been without a critical stop point.

How does one stop the carriage in the when a shoulder on the work piece is there?
I witnessed a friend doing a right-hand thread up to a shoulder and he broke the tool bit by trying to plunge out by just watching. It was my tool bit.
 
I think the conclusion of this topic is:

1. Compound at 90 degrees and move left to right. Forward rotation.
2. Compound at 90 or 60 degrees and move right left with bit upside down. Reverse rotation.

Each choice depends on whether there are no close shoulders, etc.
 
Use the left side stop to limit return position, so you don't reverse into the chuck.

The experiment I did was use the left-hand stop. In reverse the carriage does not stop but keeps driving left towards the chuck.
The left-right lever jams at this point and you cannot disengage the carriage from moving. Even make an emergency stop and the motor
spins down and the carriage is still moving left, slowing down but still moving. I see a potential bad situation.
(Hope this doesn't give any ideas to someone out for a revenge mission on a work associate....)
 
I once needed 8 TPI and the best I could get was 11 TPI. So I asked a friend and went over to his place and he did 10 TPI on his
Taiwanese VFD powered lathe. But first he destroyed my threading bit. Luckily for me it was a cheap cemented carbide import.
What an embarrassing moment for a Hardinge owner. :o

It sure was a lot easier to go from English to Metric on his machine than mine. I think the Hardinge design has a built in safety
factor. It's as pain in the ass to change over and that give you plenty of time to triple think what you are doing ...:scratchchin:
 
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My Feeler is an English/Metric machine; it’s super easy to switch. My Webb/Whacheon needs a gear change for metric, but I’ve got it down to an art. :)

Got rolling on threading the shafts @ 9 TPI LH on the Webb today; working great. Honestly, with 35 shafts to thread, and 45 more to be made after these, it’s better to do them in the bigger machine anyway. The forces unleashed cutting a 9 tpi thread are not trivial; the bigger machine is made for it.

However I am bummed I can’t use the Feeler to cut the smaller number of shafts that get a 9 tpi RH thread. Would’ve been slick, threading up to that shoulder.

OT digression because dang, these HLV type machines are nice... grin....

I did get to use the Feeler to cut the two bearing seats on the shafts. That rocked. I have my hoodoo voodoo way of hitting tenth’s on the Webb, but it’s committing, and therefore spooky. I can sneak up on it with the Feeler, if I want to do it that way. I built a slow, conservative recipe for cutting the bearing pads (they were roughed-in .006” oversize on the Webb) and it was easy and low-stress, and they all came out gorgeous. A near-mirror finish and right where I wanted them. I’ll speed up the recipe (process) next time through.
 
Yep. I can see my MT5 center (on the Webb) un-flex at the end of a threading pass. It’s a lot of force. Kinda glad I can’t do it on the Feeler. :)

Just put my big boy pants on, and set up to thread towards the shoulder and did a first article. In the past, doing these, I’ve flipped over my Warn HSS-insert threading tool (my Iscar won’t flip) so that I could run in reverse and thread away from the shoulder. That puts lifting stresses on the carriage/compound and again, a 9 tpi thread makes some forces. If you don’t just nail the tool height and have a sharp new insert, it’ll lift “things”. BTDT.

The Warn (Warner? Warne? Now I forget) HSS insert threader is nice. I got it for threading rifle barrels where you want to run very slowly and carefully. And, it’s got two insert pockets, so you can flip it over and run it away from a shoulder... However, I’m out of sharp tips on my HSS inserts which I didn’t realize until I grabbed it. So, threading to the shoulder is the recipe this time.
 








 
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