I am going to buy a mill….Decisions, Decisions !!

[Jon LawesParticipant @jonlawes51698]

I chose R8 when I bought my mill and I'm glad I did; Primarily due to the extra headroom you get above the table.

[Howard LewisParticipant @howardlewis46836]

When I bought a Mill/Drill, a long time ago, I opted for 3MT, but buying now, I would opt for R8, since it is an easier taper to "break" when the time comes to remove the tools, or ER chucks.

Howard

[old martParticipant @oldmart]

I did say "if you have a choice", and Ketan has given a pretty comprehensive explanation.

[JasonBModerator @jasonb]

Dave, Ketan forgot to mention that certain red painted hobby mills have a beefier end to the spindle so the R8 hole does not weaken things.

15years ago when I bought the X3 and did not know any better I went for MT3 thinking it would be handy to swap tooling to the lathe but have done it so little it would now not be a deal breaker. Talking of breaking my balls bearings are still fine after 15yrs of hitting the drawbar with a copper hammer.

having now used R8 on the SX2.7 and KX3 with their self ejecting drawbars I would most likely go down that route even if it does mean a bit more head raising to swap tooling as you can't tilt R8 shanks like you can MT. Though I would not say no to a CNC equipped with INT20, 25 or 30

[old martParticipant @oldmart]

The Tom Senior light vertical that the museum inherited had a MT2 spindle which I was not going to tolerate. The R8 spindle lower half was bought from ARC, a spare part for one of the Sieg mills that they sell. It was a relatively simple upgrade and the two part spindle runs very well indeed.

[Kelvin JouharParticipant @kelvinjouhar72006]

Just to update this thread, I decided to order a WM16B mill from Warco and they are going to fit a 3-axis DRO for me. I already have a 3MT collet chuck and collets for my lathe, so I can make use of those, and buying a mill with the DRO already fitted means that I can get straight into learning how to use it – Thanks for all the input.

[Kelvin JouharParticipant @kelvinjouhar72006]

My milling machine has arrived from Warco and it’s ready to be lifted onto the stand. I want to buy some adjustable feet for the stand first. The tray is loose so I plan to hold it in position with some magnetic right-angle welding clamps, before I place the mill on there, I have an engine hoist to lift it. Then I can start to make some swarf !

[HopperParticipant @hopper]

Posted by SillyOldDuffer on 27/06/2022 16:36:44:

Tapping the drawbar to release the MT tooling doesn't worry me because I couldn't find any solid evidence it actually damages the bearings. There are plenty of folk convinced it must, but opinion isn't evidence!

Those folk would include all the bearing manufacturers whose installation literature says not to bang on bearings with hammers because it causes brinelling and early bearing failure. EG, from Barden Bearings:

Any static overload or severe
impact can cause brinelling.
Examples include: using hammers
to remove or install bearings,
dropping or striking assembled
equipment, and a bearing
onto a shaft by applying force to
the outer ring.
Install bearings by applying
force only to the ring being pressfitted,
i.e., do not push the outer ring
to force the inner ring onto a shaft.

But most hobby machines do so few hours of runtime it seems most get away with it for many years without trouble showing up. Probably a different situation than say a large building HVAC fan bearing that runs 24/7 for years on end between bearing changes.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Hopper on 20/08/2022 15:27:50:

Posted by SillyOldDuffer on 27/06/2022 16:36:44:

Tapping the drawbar to release the MT tooling doesn't worry me because I couldn't find any solid evidence it actually damages the bearings. There are plenty of folk convinced it must, but opinion isn't evidence!

Those folk would include all the bearing manufacturers whose installation literature says not to bang on bearings with hammers because it causes brinelling and early bearing failure. EG, from Barden Bearings:

Any static overload or severe
impact can cause brinelling.
Examples include:…

But most hobby machines do so few hours of runtime it seems most get away with it for many years without trouble showing up. Probably a different situation than say a large building HVAC fan bearing that runs 24/7 for years on end between bearing changes.

Bearing manufacturers do give that "don't hit" advice and their reasons are convincing. Against that Morse Tapers have been ejected on a large scale by tapping the drawbar for about 150 years and I've never seen mention of a failed bearing.

I can think of a few reasons why the failure rate might appear to be low:

1. MT was used for about 80 years before ball-bearings became common. Maybe most bearing beating was done to plain bearings that don't brinell.
2. Ball bearings in milling machines are designed to take vertical thrust, and maybe that reduces brinelling compared with bearings designed to take horizontal thrust, which I think are more common type.
3. The bearings are damaged by tapping, but it doesn't significantly reduce bearing life on machines that only run intermittently. No one notices!

I like possibility number 3, but as you say, it's a different scenario to a HVAC fan and many other installations.

Let's agree Hopper's Law: "Thou shalt not fit new bearings to machines with a hammer just because a Silly Old Duffer on the internet said its OK to tap MT drawbars ."

Dave

[HopperParticipant @hopper]

Posted by SillyOldDuffer on 20/08/2022 16:12:35:

Posted by Hopper on 20/08/2022 15:27:50:

Posted by SillyOldDuffer on 27/06/2022 16:36:44:

Tapping the drawbar to release the MT tooling doesn't worry me because I couldn't find any solid evidence it actually damages the bearings. There are plenty of folk convinced it must, but opinion isn't evidence!

Those folk would include all the bearing manufacturers whose installation literature says not to bang on bearings with hammers because it causes brinelling and early bearing failure. EG, from Barden Bearings:

Any static overload or severe
impact can cause brinelling.
Examples include:…

But most hobby machines do so few hours of runtime it seems most get away with it for many years without trouble showing up. Probably a different situation than say a large building HVAC fan bearing that runs 24/7 for years on end between bearing changes.

Bearing manufacturers do give that "don't hit" advice and their reasons are convincing. Against that Morse Tapers have been ejected on a large scale by tapping the drawbar for about 150 years and I've never seen mention of a failed bearing.

I can think of a few reasons why the failure rate might appear to be low:

1. MT was used for about 80 years before ball-bearings became common. Maybe most bearing beating was done to plain bearings that don't brinell.
2. Ball bearings in milling machines are designed to take vertical thrust, and maybe that reduces brinelling compared with bearings designed to take horizontal thrust, which I think are more common type.
3. The bearings are damaged by tapping, but it doesn't significantly reduce bearing life on machines that only run intermittently. No one notices!

I like possibility number 3, but as you say, it's a different scenario to a HVAC fan and many other installations.

Let's agree Hopper's Law: "Thou shalt not fit new bearings to machines with a hammer just because a Silly Old Duffer on the internet said its OK to tap MT drawbars ."

Dave

Let's not get too carried away.

As I said, hobby machines run so few hours compared with other bearing applications. So even if you reduce a bearing's running life from 100,000 hours to 10,000 hours by beating on it, that would still keep most hobby mills running for 20 years or more.

ISTR the big old Cincinnati mills I worked on for a while as a spotty faced yoof had captive draw bars that you unscrewed with a spanner, putting the stress exclusively on the spindle and the toolholder without involving the bearings at all. Those would have been some expensive bearings on an 8 ton machine so maybe they were cautious about them. But IIRC the little Bridgeports had a drawbar you whacked with a hammer ( or the spanner in your hand already if the leading hand was not looking) but they were an R8 or similar self-releasing taper that did not require the kind of whack a self-locking Morse taper would require. That is possibly one reason Bridgey changed from Morse to R8 in the first place.

Edited By Hopper on 21/08/2022 00:21:34

[SillyOldDufferModerator @sillyoldduffer]

Posted by Hopper on 21/08/2022 00:11:17:

Posted by SillyOldDuffer on 20/08/2022 16:12:35:

Posted by Hopper on 20/08/2022 15:27:50:

Posted by SillyOldDuffer on 27/06/2022 16:36:44:

Tapping the drawbar to release the MT tooling doesn't worry me because I couldn't find any solid evidence it actually damages the bearings…

Those folk would include all the bearing manufacturers whose installation literature says not to bang on bearings with hammers because it causes brinelling and early bearing failure. …

Bearing manufacturers do give that "don't hit" advice and their reasons are convincing. Against that Morse Tapers have been ejected on a large scale by tapping the drawbar for about 150 years and I've never seen mention of a failed bearing.

I can think of a few reasons why the failure rate might appear to be low…

Let's agree Hopper's Law: "Thou shalt not fit new bearings to machines with a hammer just because a Silly Old Duffer on the internet said its OK to tap MT drawbars ."

Dave

Let's not get too carried away.

…

But IIRC the little Bridgeports had a drawbar you whacked with a hammer ( or the spanner in your hand already if the leading hand was not looking) but they were an R8 or similar self-releasing taper that did not require the kind of whack a self-locking Morse taper would require. That is possibly one reason Bridgey changed from Morse to R8 in the first place.

…

We appear to be enjoying a violent agreement!

Your comment 'they were an R8 or similar self-releasing taper that did not require the kind of whack a self-locking Morse taper would require', reminded me of another reason Morse Tapers aren't the best system ever invented. It is that the drawbar can be overtightened by the operator and if he does this to a cold tool inserted into a hot machine the resulting grip is hard to break. Worse if the assembly is left for a long time and the oil gums or the metal corrodes slightly.

Clean MT tapers in good condition don't seem to need the drawbar to be tightened much, and in my workshop MT tapers release with tap or three.

• Drawbar, finger tight plus about 3/4 of a turn with a spanner: certainly not spannered down hard.
• With the drawbar undone 3 or 4 turns, the taper is released by a medium sized hammer driven by a flick of the wrist into an Aluminium pad that protects the drawbar nut.

I've not experimented properly, but small hammers swung hard don't seem to break the taper efficiently, and neither do big hammers. I suspect the timing of the impact is as important as the amount of energy in the blow. Small hammers move fast, but have insufficient weight in the head, whilst big hammers have plenty of energy, but move too slowly. There's a sweet spot.

The sharp tap I give the drawbar is far from bang bang ferocious and I don't worry about it. Would be interesting though to spend a day inserting and removing MT taper tools before stripping the machine down and inspecting the bearings with a microscope.

I have a notion that most of the energy in a successful taper release is dissipated as heat because work (physics definition) is done against friction. The amount of energy reaching the bearing might be quite low. Not so if the blow doesn't break the taper; then the energy must end up in the bearing and might damage it.

Dave

[derek hall 1Participant @derekhall1]

On my Emco FB2 mt2, I finger tight the drawbar and only a fraction of a turn ( less than an 1/8) with thumb and fore finger on the Allen key is enough to hold it in place.

The special small nut at the top of the spindle and the drawbar is used to release the mt grip

But never over tighten!

Derek

[Bo’sunParticipant @bosun58570]

My Warco WM16B has a No.3 MT, and while the manual says to tap the drawbar, it doesn't work. A call to Warco revealed my WM16B to have a threaded nut that pushes the taper free. Takes a bit longer to release the taper, but works OK. Just don't over tighten the drawbar.

[Kelvin JouharParticipant @kelvinjouhar72006]

I now have my mill set up and I am starting to learn how to use it. I am very glad that I had the DRO’s fitted – I am now thinking about a Powerfeed. I have seen threads where people have fitted DIY power feeds to this mill, but I wonder whether anyone has fitted the Warco Powerfeed to this mill.

[not done it yetParticipant @notdoneityet]

I’ve not because I don’t have either. I made one by roughly following the video by Phil Vandelay

**LINK**

[Bill PhinnParticipant @billphinn90025]

Posted by Kelvin Jouhar on 02/10/2022 15:12:43:

but I wonder whether anyone has fitted the Warco Powerfeed to this mill.

 

I fitted a Warco powerfeed to my WM18. I'm not sure whether the kit for the WM16B will be the same; the belt driven WM16B didn't exist at the time I bought my WM18.

There were a few niggles with the fitting. Firstly, the mount for the cut-out switch needs to be adapted or the front of the mill drilled and tapped. Warco claimed at the time it could be fitted straight out of the box, but it couldn't. I see they've changed the wording now.

There's also a LH threaded retaining screw you have to insert inside the lead-screw-mounted gear, I seem to remember. Again, nothing in the manual even mentioning the existence of this screw. I just had to work out what it's for.

Lastly, make sure you optimize the meshing between the gears to give good engagement without drag.

About six months after I'd fitted mine I found a video on Quinn Dunki's blog site showing the issues she encountered fitting hers. It would have helped me to see it sooner.

I fitted it nearly three years ago, and it's worked fine since then. Hopefully not a case of famous last words.

This is the link to Quinn Dunki's article:

Vertical Mill – Power Feed

Edited By Bill Phinn on 02/10/2022 21:39:31

[Kelvin JouharParticipant @kelvinjouhar72006]

Thanks very much Bill.

[Author]

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