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One advantage of cross slide is that it is more rigid than compound -some people get rid of their compounds and make solid blocks with tools posts.If you have chatter problems-especially on small weaker hobby lathes that affect the quality of your threads consider locking the compound and use small depth of cut with cross slide. Big heavy duty rough cutting industrial lathes dont even have compound slides and they use block tool posts instead of quick change tool posts.If you have a chinese lathe that may be your source of problems ,cheap quick change tool post +low rigidity of compound slide = chatter and bad thread quality . Sharp tool with proper geometry and right speed +smaller depth of cut and several passes can get the job done even on cheap chinese lathe.

Please Sir, How much do you want for one?

There is another method that is equivalent to using the compound set at 29' Set the compound parallel to the lathe axis and feed the cut with the cross slide but feed the compound one half the cross slide depth of cut. This means the depth of the thread can easily be read from the cross slide but moving the compound one half the depth of cut is equivalent to setting the compound to almost 29'

Good video ,Mark and specially when you question and answer yourself and not just telling the solutiom.Trial and error.Thank you.

In all videos about this machine I have never seen a demo of what the rear knob does and how to do it. Can you show?

You are correct.

Feeding in with the cross slide makes it easy to see the exact cut depth on the dial. To cut on the leading edge and almost exactly simulate a 29 degrees feed in. Advance the compound half the depth of cut per pass with the compound set at zero, parallel to the spindle.

Very interesting, I am generally happy if the thread is just fit for purpose and I don't have to redo it!!!

I've tried both methods and now plunge straight in. I go from left to right at higher speeds and use plenty of cutting oil, HSS tool. 1440 lathe. Decent threads. I've got carbide inserts but they are never as sharp as my HSS. Especially on quite small threaded things the inserts seem to want to push too much before cutting.

Perhaps a contributing factor in the difference of finish between cross-slide with insert and cross-slide with your very clever ½ threading HSS tool might be how carbide cuts your workpiece vs HSS? (assuming your ‘factory tool’ was a carbide insert?. Love your videos and your thinking!

lol hay mark.... how about trying to improve on the cutting tool for threading ? why not give the half-tool a relief so it actually cuts instead of having the chips slam into a flat surface on the tip of the tool.... it has always bothered me that threading kind'a rubs the chips off instead of cutting them off and inserts only slightly improved upon this but the area is so small you still get a flat area on the cutting edge... so why not just cut a relief behind the tip of say 5 degrees so the chip is actually cut ? may not work for hard metals like stainless steel , or that may only work on soft metals, aluminum and copper,etc,etc. but the reality is if it works on mild steel we all would be far better off using a half tool with a relief ! because when I thread i hardly ever get good clean threads so I have to run the corner of the file in the thread groves to clean then up. a half tool might well cure that for me ! thanks Winky !

I think what proved the point that using the compound at 29.5 degrees is better is when you used the "half threading tool" it couldn't cut on both sides because there weren't 2 sides ! yet the threads came out best of the lot ! it also shows that threading inserts are not always as sharp as they could be ! a super sharp threading tool really makes a big difference !

I was afraid you were about to step on the third rail for bringing this up. Other channels have expressed their opinions and then gotten lambasted from all sides. Strap on your thick skin and smile. 🥸👍👀✅

Thank you for sharing this informative video. I enjoy your channel very much. For MANY years I did all of my single point threading with 3/16" square HSS tools held in an Armstrong style tool holder held in a "lantern tool post" on a 6" Atlas/Sears lathe. Side rake was ground into the tool (leading edge only) and back rake is set via the Armstrong holder. The feed was put on with the top slide set at 29.5 dgr. The look and feel of these threads was, IMHO, consistently good. Recently I began using a genuine Aloris (wedge style) tool post with AXA tool holders and 3/8" square HSS tools with a 9" South Bend workshop lathe. The plunge feed is put on with the cross slide as suggested in many internet videos. Threading results are rather poor. I attribute this to no back rake and no side rake. In other words, the tool is basically scraping, not cutting. I have also tried feeding with the compound set at 29.5 dgr. The results are somewhat better on the left thread flank (leading edge of tool) but finish on the right thread flank (trailing edge of tool) is "smeared and flakey" even though there is plenty of side clearance. I plan to try treading with the South Bend lantern tool post, Armstrong tool holder and 1/4" HSS tools with this "new" lathe. I'll let you know how it goes. For what it's worth, F.C.

I was taught to thread with the compound @ 29.5 degrees almost 60 years ago. I have tried to cut threads with just the cross slide and it wasn't pretty. It seems the Aussies (Kurtis of CEE and Max of Swab valley) thread using the cross slide to cut the thread depth. Max explained that he sets the compound parallel to the work piece. When he advances the cross slide X amount he then advances the compound X/2 amount. Then proceeds to cut the thread. The video showed good results! Maybe you could try this method out and give us the results. KOKO!

I hope you get the viewing hours you deserve! I've found it difficult to create a video that holds people's attention! I'm just a boring old guy!

Big difference between cutting gummy stock at slow speed with carbide insert, and cutting same gummy stock at same slow speed with a high speed tool bit! Carbide insert will produce much better chip and profile cutting faster than you showed. As for which method is better ? I always like to keep it simple using Cross Slide instead of Compound, especially if thread pitch dia has to be within given tolerance measuring with wires or Thread Mike. You can always take several finish "air passes" for full profile carbide insert finish with Cross Slide if required. And/or even at that point, micro adjust produced thread profile with your Compound if necessary on last pass.

Going to make a Acme compound replacement rod for my old lathe. After this video, considering changing how I planned to cut it. Need to make a 52t gear first. Know what I will be doing in the next few days. Thank you for showing 'how to'.

I use the compound set at 29 degrees for two reasons not mentioned. Cutting with the cross slide means you have to remember the depth of the last pass. I can't have any distractions of any kind while cutting threads using this method. Total concentration is required... at least for me. Secondly, by bringing the cutting tool up close to the work and turning the cross slide handle to about the 10;30 position and setting zero, you can then bring the tool to the work using the compound slide and setting it to zero also. The advantage of doing this is that you can now run the work at 150/200 rpm and then snap the tool out of the work without having to bother making an under cut for the thread. Do it several times and you will see it is pretty easy to do... and you can impress your friends. As an aside, look in your reference book and notice that the major diameter for a thread is not the nominal diameter of the material. So, with metric or imperial the very first thing you do is turn the work to the correct diameter. Failure to do this may explain why the mating thread goes from won't go to will go with a sloppy fit and undersized pitch diameter in one pass. Correctly cut, the flat crest of a 60 deg. metric or imperial thread is 1/8th the pitch. You can cut a class 1 thread to size by just looking at it. Cheers from NC/USA

I always use the compound. Why? Because I use HSS for threading and if I feed straight in the tip of the tool always chips off halfway though! Might just be chinesium HSS though.

Your printed illustration was far better than any other shown before on CZcams. Great demonstration. Thanks for the video!

Little threads, cross slide, big threads, compound. Works for me.

BTW I suggest you add a "Super Thanks button"

Mark since You Tube does not rank creativity I will give you my own ranking. I am ranking you as a "Master Creator". This is an excellent demonstration and narration of one method verses the other. I always like the way you think the process all the way through.(easier on the spindle bearings) Unlike me I just turn the camera on and what you see is what you get and non-edited. But mine is only for documentation purposes only. I love the detail of how the chips looked. Cross slide seams to tear the chip where the compound shears the chip. i always say "Anyone can make chips but knowing how the chip is made separates the men from the boys." thanks as always for bringing us along.

Something that hasn't been mentioned is the chip flow. When feeding with the carriage, it produces two chips which must compete for the same space. It was pretty obvious watching when feeding straight in.

Me not knowing ANYTHING about cutting threads, doesn't it make a difference with the type and sharpness of the particular tool you are using?

Loved your half thread tool👍

thank you so much, have a wonderful Independence Day my Friend, Paul in Orlando

I did the same test many years ago cutting a 12x1.5 thread in 303 stainless using a 1,5 pitch full form insert, even under a microscope you couldn't tell which was which.

Great little discussion Mark, I agree with you. The professional machinists at the steell mill typically cut very nice threads with the insert tool and the cross slide on heavy lathes, while at home I preferred the 29 degree solution for my lighter lathe. Enjoyed very much, cheers!

For the mainly small threads that I make, I do it as follows: - 1st pass straight in with the cross slide, depth about 1/3 of the thread height (there is little material to remove). - 2nd pass usually 0.2 mm deeper and the compound 0.1 mm forward. - 3rd and subsequent passes usually 0.1 mm deeper and the compound 0.1 mm alternating back and forth - last passes 0.05 mm feed and +/- 0.05 mm flank shift - A few spring passes without cros slide feed and +/- 0.01 with the compound Always nice smooth flanks and no hassle with compound angle adjustment. Lubricate well!

Interesting concept

This is one of those things that has passed from knowledge into myth over time. Only the techniques survive and the original reasoning is lost(as has happened to a number of other things). Threading CAN be done either way, in fact there are even more ways than that which are options on CNC lathe programming. For manual work it boils down mainly to these two techniques. Is there one more "proper" than the other? Yes there is and there are reasons for it. Cutting with the compound was used , not to complicate your life needlessly but to overcome real problems in doing the best possible work. The 29.5° compound method has these advantages. 1 The load on the tool is strongly biased against the direction of the feed, keeping the half nut securely and consistently engaged. 2 The chip load is very much reduced by not having two heavy chips colliding from 2 directions right over the weakest part of the tool. 3 The alignment of the tool can never be "perfect" and the 1/2° - 1° skew ensures the right side skims clean if slightly off. 4 The in feed per pass is twice as sensitive and precise relative to the PD because taking off mainly only one side. Ultimately both techniques are usable in different scenarios but the 29° method is better in most cases even if you can get away with the cross slide sometimes it will pay dividends to know and use both. Personally I use the 29° method for all critical threads, most threads in steels and reserve the cross slide method for soft metals and non critical threads. I mix and match the two, using the 29° method for the bulk of the thread then often switch to the cross slide for skimming the final clean up sizing cuts where the load is light and because of the direct 1:1 relationship of cut depth to Pitch diameter.

My Dad taught me to thread with the compound set at 29 degrees almost 60 years ago. He explained the reason as you just did. i never questioned it, and always got good results. Good Video, clear, and concise.

Excellent information winky, great video, keep'um coming.

I always liked cross slide more althou we were taught both ways.Its simplier to get a correct depth of cut -you use marker on a blank and then do the skim pass to check thread pitch,0 the cross slide dial and then you feed to the wanted depth.If geometry of the blade is good (when you grind hss for example)you will get a great fit by just using the dials.With practice over years you dont need thread micrometers or pin gauges or anything like that. Something that i was never able to get with compound method .

Always good to do some experimenting. Ideal way to figure out what works best.

I had a big fight with jo pie about that. He made 1 video claiming it DID cut on the right side and then made a different video claiming it DIDN'T cut on the right side. He got VERY nasty about being called out on it. Even made an insulting video just about our argument. Of course he banned me from commenting on it and I unsubscribed and never watched his channel since.

Rigidity will indeed be a big factor, as will material. I tend to feed with cross slide on my lathes, but they're quite a bit larger than yours. I think this is the first threading demo I've seen where the machinist took a deep initial cut and then decreased progressively as the thread formed. Most people do 0.005" or so all the way in. Big waste of time. Great demo well explained. Thanks.

👍👍

The intro was perfect, the visual aid was spot on, you should have stopped while you were ahead. Carbide vs HSS with completely different geometries. Feeding 5 thou on a thread like that and wondering why the surface finish is terrible? I don't know whats worse, this video or some of the completely clueless goofballs in the comment section.

Mark is dead right about the ridgidity of the lathe. It is the main factor. I don't cut many threads but when I do it's compound driven. 29° for 60° threads and 27° FOR 55° threads (whitworth), close enough. I get much nicer thread on my rubber lathe 😂.

From videos I've seen, the straight-in method works fine for fine, shallow threads. Maybe another experiment with 28tpi?

Great visual with that printout 👍🏻

I found the noise in my South Band 10L. It all came from a loose set screw on my electric motor pulley. Once it was tightend, it now sounds like a sewing maching.

I noticed the run-out changed during the processes! But I vote COMPOUND. Or single Point.

Thanks for the interesting demonstration which you covered very well. I like feeding with the compound with a very small positive rake on the tool. Go straight in on the last couple of spring passes for a perfect thread.

A good topic to start a fight in a Machinist bar. LOL I also prefer using the compound. When I need to make threads for my wood lathe, 1 1/4in x 8 tpi, even with using the compound I have to take light cuts due to the amount of metal being removed. As you said, the sharp "half" threading tool made some really nice looking threads. Well done. Dave.

Great video. Have completed any drawings yet?

I mostly use Geometric auto die heads whenever I can. But it’s difficult to get all the chasers these days. Also my biggest head goes to 1”, so anything g larger needs to be single point cut. No matter how many decades I’ve been doing that, I’ve always thought of it a real pain. I’ve been thinking of making one of these things, but there are a number of people making them, some better than others. This one looks nice. I think he has a couple of videos up. The 1” retract is the latest model. If he’s selling these, I might get one.