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Black Forest
03-13-2011, 12:59 PM
I need to buy some threading tools.

My tool supplier handles Walter tool holders and inserts.

The book only shows the holders and inserts that lay horizontal. I have only seen the vertical type of insert and holders.

Do you all have a preference? This would be single point type inserts. I am not sure if I will make a retractable holder or a swing holder.

Toolguy
03-13-2011, 02:03 PM
I prefer the laydown kind myself. You have a lot more choices. For example, you can get just single point or full thread form, acme, round crest and root, etc. They all fit the same holder for a given size.

Forrest Addy
03-13-2011, 02:16 PM
Hand grind your htreading tools from HSS. Once you've ground a few tools your get practiced so they go qiuckly. HSS threading tools give better finishes at the very slow threading speeds most people seem to feel obligated to use and they generally ;ast longer than carbide under slow conditions. It's only on CNC machine where threading takes place at carbide speeds that carbide threading tools work better than HSS.

But you wanted to know about vertical threading tools. I prefer Kennametal's offerings. They are a little more expensive but they hold the inserts better. I also like the double end insert style with the top clamp.

shadtree
03-13-2011, 04:55 PM
I agree. The carbide doesn't seem to like the slower turning speeds. Cuts a ragged thread. Use HSS. The satisfaction from grinding a turning tool and cutting nice threads is hard to beat. Good Luck.

Black_Moons
03-13-2011, 05:33 PM
Carbide also has this nasty habbit where if you ever stop the lathe with a carbide tool engaged in a cut, It will often snap the tip. Ie, if you stop the lathe just before the runout groove.. hss will often survive.

PixMan
03-13-2011, 06:50 PM
I prefer the laydown kind myself. You have a lot more choices. For example, you can get just single point or full thread form, acme, round crest and root, etc. They all fit the same holder for a given size.

Same for me. I have a growing collection of full-form (a.k.a. cresting) inserts for inch threads and ISO metric threads, plus a variety of holders. While I also have some of the "Top Notch" style threading tools, I prefer the smooth, burr-free threads that I get using those lay-down threading insert tools.

Sorry for the somewhat fuzzy mobile phone photo.

http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/2011-02-08_21-20-20_655.jpg

Another considerations include that of how close one can get to a shoulder on the workpiece. When using "generic" threading tools, you often need a wider relief groove than you would with a pitch-specific cresting insert. More, the full-form inserts (especially when making metric or UNJ threads) give you the required controlled root radii.

I find it especially nice to use them for another reason: If you make the pre-threaded diameter close to the nominal (but not below for an external, above for an internal), the insert takes the last couple of "thousandths" or fractions of a millimeter and give a nice, proper profile.

Lastly, let's not forget that the grades of carbide for threading are engineered for slower speeds and are tougher (less prone to chipping) than most other types of turning inserts. I believe that's because of the fine profiles of the insert mold. The inserts would be too fragile if made from the high-speed, wear-resistant grades.

http://img.photobucket.com/albums/v466/kenm10759/wheel-adapter/IMG_0398-r.jpg

That's 316 stainless steel, threaded (if I recall correctly) at 210 RPM. The relief "radius" groove is not smaller than the root of the thread, so the tool was pulled out manually as it reached the groove. It's not rough as it may appear, as there's some debris from the Norton Beartex deburring wheel I used to touch up the burrs around the cross hole. The thread is really quite smooth.

Black_Moons
03-13-2011, 06:57 PM
Yea Iv had my thread crest form actualy bind inside another thread.
the OD was correct on my external thread, but because the threadform had square crests and the mating internal thread had rounded crests, the crests binded.. And threading deeper would of ended up in a very loose thread before it made the crests skinny enough. (Would of had to turn down OD to correct for it, or have a proper toping insert)

Thankfuly, I was close enough that apon insertion with a strap wrench, the internal thread rounded the crests off for me. :P