Yes sir, I am...here’s another look.
First threading attempt
- Thread starter Butch Bradshaw
- Start date
I just square up the tool with face of the work...
You might have your compound set to the wrong angle. The tool should feed down the face of the backside of the thread. As an alternative, feed straight in with the cross slide. With these fine threads that will work fine.
It's a Grizzly G4003 so the compound is set to 60* I believe that correct for these machines...I also feed from the compound.
I use sulphur based for some materials and speeds. I also use WD40 for others. And for some stuff I do not use any lubricant.
dirtworks5
Gold $$ Contributor
Make sure you are engaging your thread on the same number on your dial each time. You have to pay close attention to this until you learn your lathe.
Dusty Stevens
Shiner
Does a grizzly engage on a line or number for even thread pitch? Something aint right with the shape of those threads
I have the same trouble with mine, damn halfnut just won't release sometimes, run it upsidedown and backwards 400 rpm and a lefty shim with a laydown carbide tool and it works great no crash and looks a thousand times better.
Took apart the crosslide assy to get to the halfnut mechanism to try to figure out why it would hang and can't find any reason, nothing wrong it just won't release under cutting load consistently, said screwit and started going bass-ackwards and haven't looked back.
If you only cut 16 tpi or 20 tpi and don't do a wide variety of thread pitches you can get carbide bits that cut the full thread profile for that tpi, works even better. Nothing wrong with a HSS or M42 cobalt 60 deg standard square bit, but the carbide laydown setups are slicker than reindeer slobber.
What kind of stainless? 300 series stainless and a HSS bit its going to look bad regardless. Barrel steel is 400 series (high chrome) usually 416R and machines MUCH MUCH easier than 300 series.
Dusty Stevens
Shiner
Dont thread backwards if your chuck threads onto the spindle- lil public service announcement.
These were cut with the half nut engaged on #1, at 70 rpm feeding from the compound at 60* with a full form carbide bit. It may just be the photo as the threads look good to me. The receiver screws on tight by hand.
I'm thinking this is 316 stainless, but am not positive.
It is a cam lock, so no worries. thanks
linebaugh
Silver $$ Contributor
Either the camera angle is messing up the picture or there is something wrong with the threads. Not a big deal because you will get it figured out and this is learning the ropes. It appears on the shoulder end that the tops of the threads are fuggered up and it almost looks like the threads were cut in reverse as they appear to lean back toward the chamber end.
No worries if it's just a picture thing. No worries if it's not either. Nobody is perfect and we all learn and continue to learn as we go.
My guess, as others have stated, is that you are engaging your half nut out of position or you are cutting too deep per pass. Pick a number on the half nut and stick with it. Here are a few tips from another non professional.
Use a good dark cutting fluid.
I use carbide now.
I also square up off the face and check with a simple stamped thread set up tool.
The higher the RPM you can get comfortable with, probably better results.
Don't stop the machine with the cutter engaged. Learn to pull out of your work piece under power. This will save you a lot of tooling.
My machine does it's best work at 59 degrees. It's probably simply marked a little wrong.
I run light passes and only advance my compound cross feed .0025-.003 typically. Takes more time but I get smoother cuts and longer tool life. We are cutting threads not ripping them. Look on youtube if you wanna see some thread ripping by "gunsmiths". Some of those guys I think would cut in one pass if the tooling would hold up. Also if you make a pass and can go back over it at the same setting and remove metal you are probably going to deep per pass.
On barrel tennons I never disengage the half nut, in fact I don't even bother to engage the dial. I lock in the half nut and use the bump button to advance with my left hand and I pull out of my work piece with my right. I then reverse back to the beginning of the tennon and start over all still engaged. I started doing that early on and it stuck.
At some point you need a barrel nut or an action to start checking and getting a feel for your work.
I typically hit my threads with scotch brite when finished to burnish any small sharp edges off. I don't spend much time at this, just a quick couple passes is all it takes.
The camera on your cell phone zoomed in a bit can be a real help with squaring up your tool on your breech face. It's also extremely helpful when picking up threads if you need to do this. Found this out about a month ago.
Hope that helps. Keep up the good work and thanks for posting.
No worries if it's just a picture thing. No worries if it's not either. Nobody is perfect and we all learn and continue to learn as we go.
My guess, as others have stated, is that you are engaging your half nut out of position or you are cutting too deep per pass. Pick a number on the half nut and stick with it. Here are a few tips from another non professional.
Use a good dark cutting fluid.
I use carbide now.
I also square up off the face and check with a simple stamped thread set up tool.
The higher the RPM you can get comfortable with, probably better results.
Don't stop the machine with the cutter engaged. Learn to pull out of your work piece under power. This will save you a lot of tooling.
My machine does it's best work at 59 degrees. It's probably simply marked a little wrong.
I run light passes and only advance my compound cross feed .0025-.003 typically. Takes more time but I get smoother cuts and longer tool life. We are cutting threads not ripping them. Look on youtube if you wanna see some thread ripping by "gunsmiths". Some of those guys I think would cut in one pass if the tooling would hold up. Also if you make a pass and can go back over it at the same setting and remove metal you are probably going to deep per pass.
On barrel tennons I never disengage the half nut, in fact I don't even bother to engage the dial. I lock in the half nut and use the bump button to advance with my left hand and I pull out of my work piece with my right. I then reverse back to the beginning of the tennon and start over all still engaged. I started doing that early on and it stuck.
At some point you need a barrel nut or an action to start checking and getting a feel for your work.
I typically hit my threads with scotch brite when finished to burnish any small sharp edges off. I don't spend much time at this, just a quick couple passes is all it takes.
The camera on your cell phone zoomed in a bit can be a real help with squaring up your tool on your breech face. It's also extremely helpful when picking up threads if you need to do this. Found this out about a month ago.
Hope that helps. Keep up the good work and thanks for posting.
carlsbad
Lions don't lose sleep over the opinions of sheep.
cut one feeding with the cross slide. Lock the compound. If you're threading in reverse away from the chuck, use 200 to 350 rpm if you're comfortable with it and see what it looks like.
Looking at the photo, unless it's an optical illusion (which can happen in photos) you have an angle problem. I don't know if your compound should be set at 30 or 60 because you never know where the zero is from lathe to lathe. You should be 30 degrees from the cross slide or 60 degrees from the spindle. the threads should be an equilateral triangle. if you feed with the cross slide, you can't mess it up. Every beginner should start feeding with the cross slide.
Looking at the photo, unless it's an optical illusion (which can happen in photos) you have an angle problem. I don't know if your compound should be set at 30 or 60 because you never know where the zero is from lathe to lathe. You should be 30 degrees from the cross slide or 60 degrees from the spindle. the threads should be an equilateral triangle. if you feed with the cross slide, you can't mess it up. Every beginner should start feeding with the cross slide.
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stick an insert or your thread tool into the threads you cut I think you will see the issues the left side looks like compound is set wrong as if its feeding away from side of thread instead of parallel to it or threading tool is set wrong like tip is off to right. I also see what looks like a double cut on crest of thread...
General rule of thumb is if your thread TPI is evenly divisible by the lead screw TPI you can engage on any numbered or intermediate notch. So 16 and 20 TPI on a 4 TPI lead screw don't have to worry. Odd TPI like 11 1/2 or 13 the numbers have significance. If you have a manual for the lathe this subject should be covered. Testing on scrap will reveal whether this is fact.
Butch Bradshaw, looking at your picture I know what's causing your thread to look like it does because I had the same issue when first learning. When feeding in with the compound, the compound angle needs to be shallower...I don't know how the grizzly compound is marked, 30 degrees vs. 60 degrees from what reference...I'm having a difficult time coming up with the proper description, as do many people (this is why, at least to me, verbal or written directions on this topic are often difficult to understand). But a picture is worth a thousand words so here's two pics I stole from the interwebs. You want your compound angle to look like the second picture. The first will result in what you are getting. Set like the second picture, the shallower angle, your degree markings will read either 30 or 60, depending. but basically you have been feeding in too steep. Been there, done that. Let me know if any of this makes sense!
edit to add; I just re-read what I wrote here earlier and it confuses even me! The steep vs. shallow, maybe ignore that. but the pictures are good.
edit to add; I just re-read what I wrote here earlier and it confuses even me! The steep vs. shallow, maybe ignore that. but the pictures are good.
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