What is your favorite end mill and usage

[Susquatch]

IMO that is a lot & needs to be dealt with. Pulling side to side like that is a good way to get a feel for slack especially if you have an indicator mounted to quantify what you are suggesting is 0.100" on both X & Y axis. Having float on both axis is double the fun because it is free to roam in an area as opposed to just a line as if only one axis had wear & the other locked. However its those temporary unlock transition moments when you set up for another traverse (just like you described) where the surprise can bite you.

Most people phrase this effect it in terms of dial backlash, its really the same thing. Its nice if you have DRO for following test but can do as easily with DTI in spindle against a reference block edge.
- dial in-feed direction only, say 3 turns so leadscrew backlash is fully taken up, don't reverse dial direction during process
- stop dial on handy dial reference like zero
- zero the DRO/DTI at this exact same spot
- slowly reverse handwheel until DRO/DTI moves off its null position, make note of how much handwheel dial movement has occurred (yours might be close to 0.100")

Video shows the ballpark shortcut without a DTI/DRO but I like the reference method more because its more repeatable & precise for what I also recommend: Repeat this at different spots on your leadscrew like 1/3, 1/2, 2/3 table displacement positions. You may find the wear is in concentrated in the middle most used area. Good to know but doesn't usually change the strategy or remedy if excessive wear is the issue. Next you need to know if you can dial this out acceptable with leadscrew nut anti-backlash adjustment as per video, so try that first.

If the available anti-backlash has been bottomed out by years of increased adjustment, then you need to pull LS assembly to examine. If you are lucky the majority wear will be confined to the brass/bronze nut (=sacrificial wear material). But if its also the LS threads, not at all unheard of, its new leadscrew time & usually do the nut as well so they are a happy low tolerance couple. I should have mentioned the dovetail gib adjustment also factors in this, but not really. Its more a tightness of fit to dovetails & angular table float. Some people crank up the dovetail tightness so it feels stiffer & floats less, but you are not fooling the leadscrew wear if that's the issue. Worse yet table can get sticky when too tight & the cutting action can easily kick the table through its float range & nasty surprise time. Wrecked part, broke tool etc. But you If you have that adjusted the gibs OK, suspect the focus is on lead screw / nut.

I have not exhaustively checked this out. I'm still qualifying the mill before deciding which one to keep. But yes, if I keep it, the Bridgeport may need new nuts and screws. The screws themselves are both visibly worn more in the center than the ends and the backlash is correspondingly worse in the middle. (see my thread "New to me Bridgeport Mill").

I have not tried adjusting them to get some out. I had planned to do a little milling first to test the mills bones out before doing anything like that. Not big jobs - just little ones like making a mill stop and vice clamps. If I decide to keep it, that will be among the first major repair jobs I do. In fact I may even install new lead screws and nuts.

I didn't really expect to break an end mill on my first job though so maybe I should rethink that......

 

[Susquatch]

A worn leadscrew / nut on a lathe manifests itself into problems similar to a mill actually. Float on a lathe means the cross slide / compound / travel can be drawn in & out of the work if allowed to roam. At minimum usually results in variable finish, variable dimensions, tool chatter.... In more tolerance specific operations like threading or especially parting off, same potential for similar WTF surprise moments.

The roughing EM is something I'd encourage to try but not a magic solution to a more fundamental machine issue. Roughers make more efficient chips for the same feed / power so generally less stress on everything. The core is thicker so more rigid, less deflection. They are reasonably priced (I only have clones). If I don't care about a parts aesthetics or fit I leave it with the little stripes resultant from side milling. Or actually liftthe table a smidge & finish pass removes a good portion of stripes. Otherwise yes, you rough with this & pop in a regular EM for finishing. So an economical strategy is if say 1/2" is your go-to EM size, nice to have the same in rougher so all the setup should be the same. just a 30 sec tool change & back in business. Finishing means measuring the part directly & adjusting the settings anyways. All EMs have tolerance +/- nominal spec. If the whole job will only take 10 minutes just use your your go to 'good' tool. But of course you will wear it faster. Its kind of an axe > saw > plane type principle to use woodworking analogy.

My lathe is in almost mint condition with very little backlash. But I understand your point.

FWIW, I thoroughly enjoy threading and often make my own fasteners and threaded joints both sae and metric.

BUT, parting off is my nemesis. I absolutely HATE parting off. I usually get the first 1/4 inch or so cut fairly easily, but things grind to a halt a little further in. I hate it so much that I have been known to use a hacksaw on a slowly spinning part.....or side-by-side passes with a parting blade and a bigger cut than necessary. My favorite trick of late is the run the lathe in reverse and flip the parting blade upside down.

I appreciate what you are saying about a roughing mill not being a solution to a more fundamental problem. It may well turn out that my Bridgeport has more serious issues than I can stomach and it will be the one I sell. I wish my Hartford was running so I could compare, but it is still waiting on a fix for the timing belt.

I'll be honest, I wish I wasn't asking silly newbie questions about milling when I really shod be fixing the machine first. But I can't really make a decision without doing a little work. And my bride is increasing the pressure to make a decision each and every day that passes.

I like your idea of swapping bits but I think you underestimate how long that will take me. That said, I'm in no rush and swapping bits is a learning experience too. I plan to add a few roughing bits to the order I will make later tonight.

 

[Susquatch]

https://canadianhobbymetalworkers.com/threads/end-mill-sharpening-jig-project.2444/

Looks like another priority project for my list! (Insert big happy smile here!)

 

[Susquatch]

Fly cutters work really well for sweeping large areas give it a go. I can get a better finish with my fly cutter than my 1" and 2" carbide insert facing endmills.

I'm chicken. Will you come over and hold my hand?

Seriously, I am quite nervous about doing that. How deep a cut can you take with one of those? And how fast do you spin it with no fear of a HSS arrow through the heart? Maybe I'll watch a few videos first.......

 

[YYCHM]

I'm chicken. Will you come over and hold my hand?

Seriously, I am quite nervous about doing that. How deep a cut can you take with one of those? And how fast do you spin it with no fear of a HSS arrow through the heart? Maybe I'll watch a few videos first.......

LOL.... Use the same RPM as a normal HSS endmill and for a 2" that's pretty slow 200 RPM. For DOC I usually just feel it out. If the mill isn't complaining you're good. A smaller DOC will leave a better finish. The cool thing about them is that you can re-sharpen them just like a lathe tool. Be forewarned..... those things throw swarf EVERYWHERE. You may want to put a curtain around the mill when using one.

 

[Tom Kitta]

My favorite EM is 12mm carbide. For 55hrc its 16 cad.
80% of work is done with it. Lasts on manual machine about 1 bucket of chips - 20L worth.

For facing I use either 2 or 3in facemills. On aluminium finish is full mirror. Very similar on steel - just touch less. I have larger FM but did not use them in a while and they are - especially 6" best on AL.

 

[Susquatch]

LOL.... Use the same RPM as a normal HSS endmill and for a 2" that's pretty slow 200 RPM. For DOC I usually just feel it out. If the mill isn't complaining you're good. A smaller DOC will leave a better finish. The cool thing about them is that you can re-sharpen them just like a lathe tool. Be forewarned..... those things throw swarf EVERYWHERE. You may want to put a curtain around the mill when using one.

OK! I'll try it.

A curtain eh! I would not have thought of that. Thanks for the heads up. They say that experience is the best teacher because she gives the test first and then the lesson. I prefer to learn from others who learned from experience. But every once in a while I plow ahead without asking and then I break something like a carbide end mill.......

 

[Susquatch]

My favorite EM is 12mm carbide. For 55hrc its 16 cad.
80% of work is done with it. Lasts on manual machine about 1 bucket of chips - 20L worth.

For facing I use either 2 or 3in facemills. On aluminium finish is full mirror. Very similar on steel - just touch less. I have larger FM but did not use them in a while and they are - especially 6" best on AL.

Wow. That's a great price! Where do you get yours? And does the 12mm require a metric collet? Or does a 1/2" SAE collet fit reasonably well?

 

[Janger]

OK! I'll try it.

A curtain eh! I would not have thought of that. Thanks for the heads up. They say that experience is the best teacher because she gives the test first and then the lesson. I prefer to learn from others who learned from experience. But every once in a while I plow ahead without asking and then I break something like a carbide end mill.......

Grab a welding magnet and a small piece of sheet metal 12" by 6" say and use it as a movable shield.

 

[Janger]

Wow. That's a great price! Where do you get yours? And does the 12mm require a metric collet? Or does a 1/2" SAE collet fit reasonably well?

Aliexpress. Tom always seems to find the cheapest sources. I buy from MZG on aliexpress often enough not as cheap as that though. And you need a metric collet. An imperial 1/2" collet is 12.7mm which is too big to grab the 12mm tool. 1/2" tool holders won't work either. Buy some metric collets as part of your order if you go that way.

 

[Tom Kitta]

Wow. That's a great price! Where do you get yours? And does the 12mm require a metric collet? Or does a 1/2" SAE collet fit reasonably well?

Actually regular coated 45HRC are just 13 CAD or so. The 55 is an upgrade. I use ER32 11-12mm to hold them.

Shipping is uber fast - like 2 weeks, max 3 weeks. They ship bulk and then Canada post priority tracked. Shipping included.

They are LARGE supplier. They have like a catalog of 100s of carbide tools. All EM sizes up to 20mm or maybe even bigger. All hardness as well - I think to 75 or maybe 85. These are expensive through. Also 20mm is expensive even in just 55HRC.

 

[Janger]

Actually regular coated 45HRC are just 13 CAD or so. The 55 is an upgrade. I use ER32 11-12mm to hold them.

Shipping is uber fast - like 2 weeks, max 3 weeks. They ship bulk and then Canada post priority tracked. Shipping included.

They are LARGE supplier. They have like a catalog of 100s of carbide tools. All EM sizes up to 20mm or maybe even bigger. All hardness as well - I think to 75 or maybe 85. These are expensive through. Also 20mm is expensive even in just 55HRC.

who's that Tom?

 

[Susquatch]

Aliexpress. Tom always seems to find the cheapest sources. I buy from MZG on aliexpress often enough not as cheap as that though. And you need a metric collet. An imperial 1/2" collet is 12.7mm which is too big to grab the 12mm tool. 1/2" tool holders won't work either. Buy some metric collets as part of your order if you go that way.

And @Tom Kitta (I couldn't quote you for some reason this time....)

I put together a kbc order that if placed tomorrow am will arrive on Tuesday. That's more like what I call UBER FAST!

But before I press go, I will put together an AliExpress Order to compare them. I've never used AliExpress so this will be another adventure. I'll prolly do that in the morning as my old eyes are getting heavy.......

If I go with KBC, they sell 12mm bits with 1/2" shanks. But I suspect the reason for 12mm is price not function. In that case, a regular 1/2" bit at KBC is cheaper than the 12mm so why bother. That said, a single 12mm collet is no big deal breaker. I can't see the sense in a metric set just yet though.

 

[PeterT]

There is nothing magic about 12mm as an EM OD so don't do cartwheels trying to get a 12mm OD x 1/2" shank sized metric cutter from KBC. Just get a 0.500" OD & you will have many more to choose from. Metric OD & Imperial shank EMs are available of course because many R8 NAm toolholders are nominal IMP. So when you really need a metric cutter you can buy one & adapt to your NAm tooling.

But that's not this discussion objective. Unlike Imperial, metric EM's are generally the same size metric shank as the cutter body. Tom is just saying he favors that nominal size & vendor. I do the same, lots of metric tooling to choose from from abroad because that is their primary unit. But metric EM means metric collet, be it R8, ER, dedicated EM holder.... etc

 

[Tom Kitta]

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.

 

[Susquatch]

There is nothing magic about 12mm as an EM OD so don't do cartwheels trying to get a 12mm OD x 1/2" shank sized metric cutter from KBC. Just get a 0.500" OD & you will have many more to choose from. Metric OD & Imperial shank EMs are available of course because many R8 NAm toolholders are nominal IMP. So when you really need a metric cutter you can buy one & adapt to your NAm tooling.

But that's not this discussion objective. Unlike Imperial, metric EM's are generally the same size metric shank as the cutter body. Tom is just saying he favors that nominal size & vendor. I do the same, lots of metric tooling to choose from from abroad because that is their primary unit. But metric EM means metric collet, be it R8, ER, dedicated EM holder.... etc

PERFECT answer. My suspicion was that the global availability of metric might reduce prices VS SAE a bit.

For now, I'll get a few metric collets in common sizes say 6 & 12 to take advantage of spot deals. Just bought four 6mm carbide bits for $20 ($5 each) on Amazon.

 

[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.

Agreed, and thanks for the link.

I just need to make sure I don't keep breaking them! LOL!

 

[Proxule]

He's an interactive "feed and speed" chart from Little Machine Shop
https://littlemachineshop.com/mobile/speeds_feeds.php

I use this too

 

[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.

I opened an AliExpress account and tried to purchase some Azzkor bits from your link. I'll be honest, I can't figure out what I'm getting, what size, or even how many. Scrolling right and left on the product images doesn't help clear things up. Maybe I am trying to hard,.... Or maybe not hard enough. Right now I'm frustrated. I plan to try again in the morning.

I also looked for some HSS bits and failed at that too. I'd like to give AliExpress a decent try, but they are not making it easy.

 

[YYCHM]

I opened an AliExpress account and tried to purchase some Azzkor bits from your link. I'll be honest, I can't figure out what I'm getting, what size, or even how many. Scrolling right and left on the product images doesn't help clear things up. Maybe I am trying to hard,.... Or maybe not hard enough. Right now I'm frustrated. I plan to try again in the morning.

I also looked for some HSS bits and failed at that too. I'd like to give AliExpress a decent try, but they are not making it easy.

It's not you. AliExpress is strange and a bit deceiving actually. I had a hard time getting my head around the presentation initially. When I ordered my first DRO I really wasn't sure what I had purchased until it arrived.

Can you provide a link to the page you're looking at.