So I have the cross slide caliper mounted and it's working great! However, either the caliper or the readings on the cross slide handle are off as I'm about 1 thou short on each rotation (.100 inch per rotation, caliper reads .099 inch). No pictures yet, but I'll get them up when I have the compound caliper mounted as well. Drilling through that hardened stainless is a bitch! Ended up buying a carbide concrete bit and it only started to throw chips once the stainless got real hot.
Totally different question now. I'm considering cutting threads for my P60 pill so the reflector can screw on instead of just rest up against it. Using a triangle insert cutting tool (60 degrees), can I just plunge it in 90 degrees to the workpiece? I've read about the whole 29.5 degree angle of the compound and it makes sense, but the precision of these threads are not crucial so I'm wondering if I can get away with 90 degrees.
sounds like things are moving along nicely I’ve used those cheap azz digital tire depth gauges to great effect on my lathe and I have a handful of their equivalent in 6in caliper form ($7 each!) to put on the drill press “mill”. They’re good enough to get close, but if I want real accuracy, I’ll use micrometers. I’ve messed up enough stuff relying on calipers not to trust them when thou’s are important. Check out the igaging DROs and similar from Grizzly, they’re not that expensive.
no idea on threading as I can’t do that on my lathe. Wouldn’t hurt to get some HSS blanks and a thread form gauge to grind your own. I just won an auction for 40 HSS blanks (1/4 to 3/8) for $30, so it’s a relatively inexpensive way to get a bunch of bits with different profiles and for different materials. Now I just need to make a QCTP for my lathe
Yeah, I was looking at those igaging DROs, but it wasn't worth it for me to basically just have a remote display. If I ended up going the Arduino route with bluetooth, I definitely would have picked those up.
I'm about to give up and just use the standard P60 brass pill with copper wrapping. All of this work for a stupid P60 pill that probably has marginally better heatsinking (really, a LT2 head can only dissipate so much heat), but at least it has a better focus and electrical path. I just keep screwing stuff up and don't think I'll be able to create 10 pills all exactly the same with the correct dimensions for the perfect focus (I found that using the plastic centering insulators allow the reflector to sit too low causing a ring around the hotspot).
Things I learned on the lathe tonight...
1) Do NOT engage the half nut for threading without realizing that the carriage lock was tightened down (but not so tight that it prevented movement). Once you reach the end of the threads and go to disengage the half nut, it won't disengage and you'll ruin your part along with a brand new $4 TCGX insert.
2) Do NOT try to thread using a standard TCXX insert. Obviously the radius is way too rounded.
3) Don't try parting a piece ever again, you suck at it Jon.
4) Attempting to hold a P60 reflector in the chuck jaws is not easy, and any machining should be done by taking only a few thou at a time, otherwise it will go flying out of the chuck.
And now for a few pictures so this isn't so boring. Attempting to machine a groove in the reflector to fit a split piece of copper pipe so that it wedges itself in the P60 host for better heatsinking. Of course I got the diameter wrong so it's not very snug. Also you can see the horrible threads that somehow actually hold the reflector in place.
Trade secret on threads for P60 parts. 20mm x 1mm pitch. Dye and tap work terrific and are also Ideal for small lights using 14500 and 16340 batteries.
I never disiengage the half nuts screw cutting until I've finished as I dont know how to work out what numbers to use on the indicator. I wind the tool in or out when I reach a texta mark on the carriage wheel (there is no graduations on my lathe here) and turn the machine of at the same time.
Inserts can come with a radius on the point to suit different pitch threads. I only use hand ground HSS tools for screw cutting. It does the job.
I always tape up reflectors to stop swarf scoring the reflective surface and try and grip the head where the step is in the groove in the jaws and feel carefully how tight I can tighten the jaws and then add a little more. It pays to re check everynow and then as they can work themselves loose.
It sounds like you are well and truly on the right path. in no time at all you will understand what the machine is telling you. All tools talk and can be understood. it just takes practice and the ability to learn.
if you understand any of the above please interpret it for me. Its good to read about your experiences good and bad. Keep it up.
Jonny I know it seems daunting right now. There are many, many things to learn. You just need to do it one bit at a time. I can't overemphasize my recommendation to watch mrpete222 on youtube for each individual skill. He spells it all out in single topic episodes.
By the way, I think your TCGX bit is 120 degrees instead of 60.
I thought they were 120 at first as well (360/3 = 120, right?), but set three equilateral triangles next to each other to form a pie and they are only 180 degrees. Maybe I'll just try buying a more pointed insert.
Oh and whoops, I was thinking the "C" in "TCMT" was the radius, but it's the relief angle. I forgot about the 21.51 designation. Looks like I should just go the HSS route though.
If I ever get my ducks in a row enough to finally pick up one of those cheap(ish) HF lathes, I think I'll just be using a port-a-band for parting off. They're not that expensive and are handy for lots of other stuff as well. You can even buy bench stands to convert them into a vertical bandsaw, pre-made or in kit form (or of course make one from scratch).
Jonny, I’ve got a bit pile of HSS blanks coming from eBay, I can stick a few in an envelope and send them your way if you want to experiment? I can’t grind a threading bit as I don’t have a gauge.
Personally, and don’t take this as a criticism, but I think you’re trying to run before you can walk. I understand that you want to get cracking on with cool stuff, but these skills take time to learn and it’s much less frustrating when you screw up a piece of scrap instead of an important part. Also try and learn one skill at a time - turning to an accurate diameter (not a trivial task, just on its own), facing, boring, grooving, parting and threading, in that order of difficulty. Each requires its own tricks and “ear” for problems, eg. I realised that my hss boring bar needed a regrind because it started singing in the cut, which it usually only does when it bottoms in a bore. Turns out that the side rake is now too small after a lot of use and it’s rubbing instead of cutting. It’s taken me a couple of years of doing projects of increasing complexity to get where I’m fairly confident that a part will come out looking more or less how I envisioned it and I still have a veeeerrrry long way to go. And that’s just with the lathe, I’m starting all over again with my “mill”!
you’re welcome, just drop me a line if you want anything. Ebay is a surprisingly good place to buy blanks too - there are basic M2 1/4 (prob too small for your lathe, 3/8 would be better) on there for 5 for $10, and fancy M35 cobalt ones for around $3-4 each in small multiples. Used there’s a huge smorgasborg, just be patient and you’ll end up with more than you’ll ever need (or have holders for)
If I can resist heatstroke in my garage for more than a few minutes, I’ll line up the few cutters I have and take a pic of them tonight. Next on my list is a shear/ finishing tool, which looks really cool.
No dice on Harbor Freight. Best they have is a 1/4 square HSS in a package with other things I don't need. I just ordered 7 HSS tool blanks and a center gage (or gauge) from Enco for $25 shipped.
Yay, I finally parted something successfully! Seemed like the key was to toss the cutoff blade on the sanding wheel for a nice sharp edge, use WD40, and have the cutoff right next to the jaws.
I drilled for the first time too. Used a center drill and then a standard gold oxide drill bit. Worked great. I broke my carbide bit on my drill press trying to drill into the last leg of the caliper, so I just cut a notch in it instead. The compound caliper will be mounted up tomorrow when I get the right length bolt.
I also took apart the compound and cleaned out all of the old sticky white lithium, replaced the brass lead screw insert, and adjust the gib. There is history behind this lathe because it came with a whole bunch of duplicated parts, like two cross-slide lead screws, extensions, and wheels. It has another compound base too where the pivot post is busted off. The sad thing is that none of the plates with angle marks on them match up with either base so that they read 0 when parallel with the cross-slide. Oh well.
Abom79 on youtube has some interesting video’s too…not really as “educational” at tubalcain (mrpete222) but seeing how he does things makes it look alot easier
I have a habit of making up excuses for not continuing a project (like actually modifying flashlights), and tonight the excuse was building a simple storage rack for QCTP tool holders and tailstock stuff. Horribly inaccurate drilling, but it works.
I’ve used those cheap azz digital tire depth gauges to great effect on my lathe and I have a handful of their equivalent in 6in caliper form ($7 each!) to put on the drill press “mill”. They’re good enough to get close, but if I want real accuracy, I’ll use micrometers. I’ve messed up enough stuff relying on calipers not to trust them when thou’s are important. Check out the igaging DROs and similar from Grizzly, they’re not that expensive.
Well done.
