Thread Cutting on the Grizzly G4003 Lathe

[@douglasthompson2740]

Did you do a video (I don't see it in your library) of installing the DRO on the G4003? I have a G4003G (gunsmithing version) which I am getting ready (finally)to install a DRO on.

[@maslyata]

Big help man … thank you

[@andyc8454]

Thanks for the great video!

[@simpleman283]

3:49 pronounced ( pie- zen-ski ) 10:54 chart 16 thread per inch = single depth of cut 0,0406 On a 30,60,90 triangle I get 0.054126588 We need more teaching about the clearance involved between nut & bolt or more info about what the handbook means. I understand if you are teaching people that don't understand the special triangles, but let's go. No one wants to take a deep dive into the real math/geometry. I may seem bitter, but that comes from my high school failing me. I took it upon myself to learn some math on youtube. People are paying big money in taxes & the schools don't care..

[@simpleman283]

Oh @hit 12:54 you said 54 thousandths. I'm lost. It doesn't really matter because I don't even have a lathe yet. I'm just trying to learn while I wait.

[@makerspace533]

@@simpleman283 A correct National Form thread does not have a sharp point, instead it has a truncated shape. So using a National Form tool, the thead is not cut nearly as deep. Because National Form cutters are made for a specific thread pitch, hobbyists generally use sharp point tools which do not have to be used for a specific thread pitch. These tools do produce a sharp point so they go to full depth, the depth you had calculated.

[@jesseblack0713]

what do you do if your lathe does not have a compound crossfeed?

[@georgespangler1517]

Good idea with the boring bar holder to square up,will be my new hands free method

[@makerspace533]

One thing I did find interesting was the fact that the G4003 does not use a 127:120 gear set for cutting metric threads. All of the lathes I have worked with use the 120:120 because 127 is a prime root of the 254:1 ratio between millimeters and inches. The G4003 uses 91:86. This comes out so close that it would not make a difference in normal short threads. But if you were making a leadscrew, the error would be in the order of 0.001" in 6". Something to keep in mind. I have never measured the actual accuracy of the leadscrew installed on the Grizzly, so I can't make any guesses on the accuracy of inch threads.

[@georgespangler1517]

I'm confused about turning both cross feed and compound,,,why is it nessary?

[@makerspace533]

The compound is used to set the depth of cut, the crossfeed is used to retract the tool when moving for another pass.

[@johnfurrier7877]

What size scales for your DRO are you using 200mm and 900mm? Great video, I have the same lathe, so this was super helpful.

[@keithnoneya]

Did I miss the part where you talked about the Thread Dial so you'd know when to engage the half nut again? I ask because my machine has 6 positions not 8 like I've seen in some of the videos. I'm trying to cut a 6 mm x 1.0 thread on stainless steel rod. Hum I know I suck at this because I ended up the with the skinniest threads I've ever seen on a screw. LOL, now I have to make that blank all over and start again. I think I'm going to practice on some scrap first. Other than that I really enjoyed the video. Thanks for sharing. Best Wishes & Blessings.

[@billdouglas8278]

So helpful. Question - I'm looking at getting my first lathe, I've been a fabricator but want to get into machine work now - been looking at the grizzly G0602 10 x 22 but thinking maybe I should wait a little longer and upgrade to a bigger unit like this G4003. What's your opinion?

[@makerspace533]

Bigger is almost always better.

[@geckoproductions4128]

I have owned and used a ShopFox M1112 which is the identical lathe in different paint, for about 7 years. I love it, buy it.

[@jjsemperfi]

I was in a similar situation. Wanted a lathe to learn on and eventually perform some general hobby making and some gunsmithing. I put a WTB add in Craigslist and a local machine shop contacted me. They have an ENCO 12x40 Gearhead lathe that they’re looking to get rid of (too small for the work they do now). Got it for an extremely good price (according to the forum I’ve been on). It should serve me well for a long time.

[@blakemilford9128]

Good information but difficult to follow. Too much “and um”.

[@bradbrinegar1419]

hey man just checking out you video. I had the same problem you have with the cross slide handle dropping down changing the angle. if you have the manual it is part number 530a that needs to be tightened. it drove me crazy.

[@georgespangler1517]

And best use a file with handle not to drive pointed end into your hand

[@SquirrelsForAll]

This was a very helpful video, thank you producing.

[@matthewklein9225]

Thread AWAY from the chuck

[@makerspace533]

This is not always a good idea. Recently a member of our makerspace was using the reverse threading technique on the same lathe as was used in this video. Running the lathe in reverse puts lifting forces on the compound and crossfeed. Lathes are not designed to take these forces. As long as the forces remain light, this is not a problem. But if you crash the tool, bad things can happen. He apparently had some sort of crash. The lifting force was so great that the right side of the dovetails on the slide was torn off. Now we wait four months for a new compound slide from Grizzly.

[@matthewklein9225]

@@makerspace533 to each their own

[@geckoproductions4128]

OK video, could have used more camera angles, like thread dial for instance. Don't need more cameras, just more editing. I noticed you mentioned MAGIC MARKER about a dozen times or so. MAGIC MARKER is a trademark. What you were actually using was a SHARPIE. Maybe not important to you, but important to the folks who make em, kind of like calling a FORD a CHEVY. Of course, most machinists us DYKEM as a marking fluid. Overall a nice video, well done.