What is your favorite end mill and usage

[Susquatch]

Its kind of like driving a car where your steering wheel has a full turn of free play until it engages the steering mechanism on either end. Yes, driving is possible but generally not a great way to operate with any accuracy. Mill table locks (and their lathe equivalent dovetail slide locks) have a secondary purpose IMO. They also prevent wear & tear on the leadscrew/nut which will see these cutting forces. The table is heavy but its on a film of oil. With leadscrew removed its not difficult to slide table back & forth by hand. The cutting forces have to be resolved somewhere & that somewhere is a tiny area called thread leadscrew contact. So its good practice to lock the 2 non-moving axis. I often don't worry about the knee as much.

Now that there was a funny analogy! I've never seen a vehicle steering system with a full 360° turn of backlash. But they all have some. Most of it is taken care of by the alignment (toe-in, caster, and camber) adjustments which make the vehicle "want" to keep going straight and also take road crown into account. Sorry, I digress.....

I see your point about table locks saving wear and tear on the lead screw & nut. But as I said, locking the Y axis didn't change anything. But @YYCHM may be on to something......

 

[PeterT]

Oh I thought your gibs were adjusted. Ya that's worth checking too. But unless its horribly loose to the extend of rocking laterally, gib/dovetail fit is more about the table resistance feel. Your 0.1" float is an issue.

 

[RobinHood]

It’s probably the gib on the axis you are moving on, as Craig is suggesting. Why? The lock engages the gib and pushes it into the dovetail. So even if the gib were loose, the lock would make the locked axis tight. But since, in your example, you are moving in X with a possible badly adjusted gib, the table can “float” in the dovetails, causing what you are seeing. What Tom was saying is to apply the moving axis’s lock a tiny bit to take up the last bit of play in the dovetail - kind of like driving with a dragging brake. It helps until you have time to investigate and adjust as necessary.

Fasted way to test is to put a DI mounted to the mill base that is indicating on the rear of the table. Lock the knee, and Y. Pull in the Y +/- direction on a table end. Observe the DI. It should not move substantially with a properly adjusted X gib. You can run the same test with X locked off and Y unlocked. Again DI should not move if Y gib is adjusted properly.

 

[YYCHM]

Yup, I did. But I bought one carbide and a few hss bits to replace it from KBC - free next day delivery....... A bit more $ than Ali Express, but faster than smell.

How did you manage to get free next day delivery from KBC?

 

[Dabbler]

BUT, parting off is my nemesis. I absolutely HATE parting off

I was there for nearly 20 years. I finally tamed the beast... There are a bunch of things that work for better parting, and I'd be hesitant to try to 'remote control' any solution path. 'Winky' in the video below had a wonderful set of ideas to get the thinking juices rolling:

 

[Susquatch]

That is REALLY COOL. Now that I have a mill, I'll be making myself one of those! It won't be exactly the same because my aloris holder is different. But I totally get the principal of the thing. And I agree with him too. Rigidity, rigidity, rigidity. Those are the three main secrets to successful parting off. But it's not always possible for me. I especially hate those parting tool holder adapters that get held like a 1/2" tool bit. They never work on anything but aluminium.

I've tried every trick in the book or at least looked at them with a very earnest sincere eye. I can part off aluminum or brass with zero problems. Regular steel works great too as long as the depth is less than about 1/4 inch. For parts or stock bigger than 1/2" OD, things go to hell in a handbaslet. I believe your friend is right though, and that may very well work for me too. I'll need to get or borrow a bandsaw though. Or maybe design something that doesn't need one.

There is one trick that works every single time, but I don't like to use it unless I have to. That is to turn the parting tool upside down and run the lathe in reverse. I feel like that is not good for my saddle, but there is no doubt that it works.

The other thing that also works sometimes is to make side by side cuts. I can often get down a half inch that way. But it's really slow going and the bit inevitably starts to bend and the cuts join. That's about when I give up and get the hacksaw or flip the tool.

 

[Susquatch]

How did you manage to get free next day delivery from KBC?

I was hoping someone would ask that question! Thanks for not disappointing me! It's really very simple.

Their shop in OldCastle (where they first started their business) is just 40 minutes away. My son drives right past there everyday on his way to work and then again on his way home. He picks stuff up for me and then swings by here on the other leg....... 8)

Same day delivery is also possible if they have stock and I'm desperate.

 

[kevin.decelles]

I do parting occasionally and based on my first experiences, I have one foot on the brake and wear a full face shield. Over the past year I've only had success, and I attribute it to alignment and speed. I recently parted some 4340 using a carbide insert. It HOWLED like crazy until I turned it on the slowest possible speed (~80 rpm). Once I got the right speed, it quieted down and cut decently. sometimes 'more' speed is better. I've learned to try different speeds in progression up/down until I hit the sweet spot.

 

[Susquatch]

Gibs loose? Not adjusted properly?

The power went out today so I haven't been able to do much of anything until it came back on a bit ago.

I think you nailed it. Using @RobinHood's suggested method it looks like I have around 45 thou sideways float on the X axis and more if I put some muscle into it. I can easy see how that would explain my shattered endmill and my later observations. I'll have to get in there and fix that asap!

Thank you!

 

[Susquatch]

I was there for nearly 20 years. I finally tamed the beast... There are a bunch of things that work for better parting, and I'd be hesitant to try to 'remote control' any solution path. 'Winky' in the video below had a wonderful set of ideas to get the thinking juices rolling:

I practically dove at my lathe first chance I got today. The distance from the top of the compound slide to the spindle center line is only one and a quarter (1.25) inches. So it ought to be easy to make something similar to the one in your video.

I had hoped to be able to use the T-slot Aloris Tool post that I bought ages ago for my old belt drive lathe and then abandoned the idea. The Aloris would make perfect parts for the job, but it looks like too much work and too much butchery. It will gather dust for another day and another job.

Unless I come up with a better idea, I might have to buy a couple of blocks of steel for the job and make something custom.

Seems to me that a left over chunk of that 1/2" plate from the Hartford Motor Adapter plate could be machined to make a bottom plate, a block of 1.5x3x3 steel could be machined to make the top block with a separate piece to hold the cutoff blade at various heights for different blades, and two 1/2" Bolts to hold the base and block together on the compound would not be too difficult and would be more rigid than my lathe can ssupport. If that doesn't work, I'll just have to invest in a 115 KVolt Lathe mounted plasma cutter....... 8).
Given how much parting off I do, it might even become a priority!

Thanks again @Dabbler!

 

[Susquatch]

I spent as much time as is reasonable reducing the backlash and gibs on my Bridgeport. For details, see the thread: https://canadianhobbymetalworkers.com/threads/new-to-me-bridgeport-mill.3491/

In summary, I got the backlash down on both axis to 75 thou at the ends and 85 in the middle and then I believe the adjustment screws bottomed out.

I also tightened the X Y and Z Gibbs as much as possible and again ran out of adjustment.

I also discovered that the y axis lock was out of sync with the table and although it felt like it was working, in reality it wasn't locking anything. It now locks the Y Axis solid as a rock. That probably explains the y axis drift even with the y-axis lock on.

Even though I don't like the answer, I can at least take comfort in the fact that there is a satisfactory explanation for the broken end mill.

Thanks to everyone for helping me understand what happened and for all the other cool lessons along the way.

 

[Susquatch]

The company I use for past two years or so is Azzkor For example https://www.aliexpress.com/item/32896890158.html?spm=a2g0s.9042311.0.0.5b284c4dr37Xu3

Remember you can do imperial stuff with metric EM and metric stuff with imperial EM - its just touch more work. 12mm is touch smaller then 1/2 but you can treat it as "re sharpened" 1/2".

Prices are so good on this carbide it is hard not to go with it.

The Azzkor carbide end mills I ordered on Aug 17th, on Ali on came yesterday Sept 1st. Two weeks. Not really that bad.

VERY CONFUSING order process, but I did get timely order processing, shipping, and tracking notifications.

The 4 carbide bits also SEEM to be very good quality on visual inspection.

Now that they have my coordinates, they are practically drowning me in offers of various types. I've always wanted to try a threading insert and a parting insert, but never had the courage to order something I might only use once and then never touch again because it's horrible compared to HSS. I have a blade and insert bits in my shopping cart with Accusize right now that I was going to get to go with a custom tool holder I am planning to make with @Dabbler's input. Perhaps I'll try to get them from Ali instead.

Also, at Ali's prices, I can see some R8 tooling in my future to replace a lot of my MT3 stuff.

I also admit that I find it quite ironic that customs takes over a week to process stuff coming from the USA, while stuff from China gets processed in less than a day....... Pisses me off in a way....