I don't know the classes. I thread until the action or brake smoothly screws on.
What I have Recently Learned About Chambering
- Thread starter INTJ
- Start date
I don't know the classes. I thread until the action or brake smoothly screws on.
Do you ever have an issue over filling the chip pan on your 1340 GT?
LVLAaron
Gold $$ Contributor
Numbers never lie.
One day I'll figure out how to clock the barrel without having to do the whole tenon, and then set things back to get it clocked correctly.
I feel your pain. I did my own stuff at home on my 1340GT for about three years. I did a dozen or so barrels over that time--one for a CRF M-70 and the rest for my LR BR rifles-- and all of them shot well. I was just painfully slow.
In the last month at work I have done a dozen barrels, and like with everything we do, repetition over a short period of time usually leads the quickest learning curve. I am still too slow but way faster than I was.
(What takes me the most time is dialing in, and on that I won't compromise. So far, my work barrels are shooting very well and I think that is a big reason why they shoot well.)
Concerning timing barrels and brakes I should add:
9. When timing a barrel or brake, do the math but aim to be 10 degrees or so shy of perfect. For the barrel, as long as it is close to either straight up or down it's good to go.
The brake has to be very close to perfect. Our brakes are titanium and have flats at the top and bottom. With the brake, once it's within 5-10 degrees I am done with the lathe. I will then torque it into place and check with levels. I will then sand the shoulder of the brake with 320 grit sandpaper to get it clocked the rest of the way.
WSnyder
Silver $$ Contributor
Divide 1 by TPI. Ex: 1/16=.0625"
.0625/360°=.00017636" per degree of rotation
Degrees it needs to turn. Ex: 25°
25 x .0001736=.00434" IE: remove .00434" from shoulder for 25° of rotation.
You will probably want to experiment and document the amount of thread crush/fit rotation the various tenons take to fully tighten from hand tight and account for that in your calculations. I like to sneak up close then tighten and loosen the joint several times to get the threads seated in before calculating the final cuts. You can't really fully tighten an action or a brake to full torque while setup in the lathe with the various spiders and chucks we use without moving your setup which is why some experience and notes will help on how much to leave for final tightening.
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Whenever I do that math and cut to the exact amount I need, I wind up going to far. So I always take off 2-3 thousands from exact.
LVLAaron
Gold $$ Contributor
I know how to calculate it after I've shouldered it... I just want it to be right the first time. Probably not worth the challenge on a manual machine. I feel better fiddling around with it and making sure everything is perfect anyway
I do keep notes on my various actions how much crush they end up having
xr650rRider
Silver $$ Contributor
I don't have any oil in the chip pan. I used a baking pan and put a drain in it. The plastic bag in the strainer has a couple rare earth magnets in it. Chips don't stick to magnet that way.
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Thanks for all the pics! I have been leery about a flush at home ever since I filled the chip pan on the 1440 GT to overflowing....
xr650rRider
Silver $$ Contributor
I think that would exceed my 3 gallon reservoir. I'm using 2 gallons of Ridgid Extreme stainless cutting oil mixed with 1 gal Type "F" ATF.
BuffaloBill
Silver $$ Contributor
I find a foot pedal on/off switch for the pump to be pretty handy.
spitfire_er
Silver $$ Contributor
I cheat for timing using this table. If you can divide by 2 and 4, and with a little experience, you can get damn close on the first cut.
With the flush system I built, it all goes into a removable tray that drains back into the sump. Rare earth magnets everywhere and a big filter. I like the collinder and cloth idea for chips which I may try. I have a funnel on the back of my lathe that gets covered when not used. My makeshift pan, which I will improve one of these days simply dumps right into the funnel. You need a larger return line than you think. A 90 degree pvc elbow and p trap type fitting allows me to store the pan elsewhere when not needed and I don't have to worry about dripping oil because I turn it up 180 degrees. My fluid shield is a 1.5" drain pipe cover that would go against the wall in your house. Fits almost perfect over my JGS floating holder.
Ball valve in-line can control PSI. Runs about 40 psi till the throat starts cutting then it jumps to about 80-90 psi.
Once you get use to whatever system you are using, you can do it without getting a drop of fluid on your lathe. I run about 3 gallons of fluid in my system.
With the flush system I built, it all goes into a removable tray that drains back into the sump. Rare earth magnets everywhere and a big filter. I like the collinder and cloth idea for chips which I may try. I have a funnel on the back of my lathe that gets covered when not used. My makeshift pan, which I will improve one of these days simply dumps right into the funnel. You need a larger return line than you think. A 90 degree pvc elbow and p trap type fitting allows me to store the pan elsewhere when not needed and I don't have to worry about dripping oil because I turn it up 180 degrees. My fluid shield is a 1.5" drain pipe cover that would go against the wall in your house. Fits almost perfect over my JGS floating holder.
Ball valve in-line can control PSI. Runs about 40 psi till the throat starts cutting then it jumps to about 80-90 psi.
Once you get use to whatever system you are using, you can do it without getting a drop of fluid on your lathe. I run about 3 gallons of fluid in my system.
Mine is not very sophisticated but here it is. I’m at work so pics are subject to what’s in my phone. Switches for bts and flood. They are run on different pumps. The flood pump came with grey mills 10gal. tank. First filter is scotchbright pads. Had a friend bend me up some steel to slope the oil back towards the headstock. Put up some angle aluminum to stop said oil from going past headstock. Cut a hole that you can’t see in chip tray and it has a drain filter. It drains back into grey mills tank that is under tray. I have a good filter that is on the line that mounts to muzzle.
Attachments
DaveTooley
Gold $$ Contributor
UN imperial screw thread calculator
Not possible on a manual lathe. I don't know what additional capabilities a CNC lathe might have- but unless there's some mechanism whereby the contact of the insert to the tenon is precisely timed to the spindle rotation it can't happen there either.
This is above my pay grade, but far as I know the only way to time threads as used in shouldered prefits (or the "clocking the muzzle" application to which you're referring) is by thread milling.
Simple double-spider rig in a 4-jaw is what I use for shorties.
Only thing I can add to the flush system topic is type of filter I use, haven't seen it mentioned before.
AO Smith water filtration setup, with 20 micron filter.
Magnets, of course- but they don't do a thing for stainless chips. Layer of the "universal" type plastic air filter stuff cut to fit in the drain pan
Alex Wheeler
Site $$ Sponsor
Even with cnc you cant get the timing perfect. Pitch diameter will change timing. Actions do have variation in the thread pd. Even if you start the thread in the same place timing will vary because the pd will vary with tool changes.
DaveTooley
Gold $$ Contributor
The stainless steel in the barrels I use is magnetic.
Dusty Stevens
Shiner
How long is that barrel you have in there? Just wondering how short you can go with that lathe
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