How tight??

[Wheat47]

I have an older Jet Mill/Drill with a #3 Morse taper tool holder set-up.
Works very well for me. Only question I have is:
How tight should I tighten the the drawbar to hold the toolholder in?
I know I need not "reef" on it. but how "loose" can it be?
Thank you .

 

[goldstar31]

Only as tight as to avoid everything slipping whilst drilling or milling

 

[Wizard69]

I have an older Jet Mill/Drill with a #3 Morse taper tool holder set-up.
Works very well for me. Only question I have is:
How tight should I tighten the the drawbar to hold the toolholder in?
I know I need not "reef" on it. but how "loose" can it be?
Thank you .

This is a good question. I look at it this way the worse thing you can do to a spindle is to spin an arbor in the taper. If you buy that then the best thing is to make sure the taper is never "loose". Since I usually work with R8 based mills holding, cutters in collets, not having the cutter spin in the collet is an equally big concern.

The problem is I haven't given a lot of thought as to how tight I'm installing something in a spindle. I'm probably tightening things up tighter than the average user. This is due to being an automation technician that has seen a lot of stuff fall apart on the plant floor due to lazy mechanics. Since I haven't dwelled on what I'm doing the best I can describe is that I snug the collet or tool holder up tight and then give the screw about a 1/4 to 1/2 more. Kinda hard to describe as it is also about feel, you should be able to feel zero slack while turning the draw bar at which point I go a bit further. I might give it a bit extra if running a large diameter tool like a hole saw.

 

[BaronJ]

Hi Guys,

The R8 spindle fitting has a locating pin which sits in the groove just above the taper. That pin is there to guide the fitting and the pin stops it rotating in the bore. Very often you find machines with the pin sheared off. A telltale sign that the tool holder has jammed at some point in its life.

Morse tapers don't have a pin ! They are a self locking taper and are designed to grip over the whole of the taper. I have a wrench for my mill drawbar, actually a Britool one, with a 100 mm long "T" bar handle, the most that I do is to tighten it with one hand over the middle of the bar. The drawbar is self ejecting and I use the same tool to eject the tool holder. I admit that I do use a four inch long piece of 12 mm alloy tube over one half when cracking the taper, but only because a 6 mm bar hurts my fingers. I never use it to tighten up.

If a Morse taper spins then it will often damage both the tool and the taper. The usual reason for spinning is a bit of dirt or swarf picked up somewhere. I always wipe the taper with a clean paper towel. Kitchen roll is good for this.

 

[awake]

The torque applied to an R8 is a very different thing from the torque applied to a morse taper spindle. Even torqued right up, the relatively steep taper on an R8 will release with a firm tap. A morse taper, however, is a very gradual taper, and torquing it more than needed to keep from spinning can lead to having to resort to extreme measures to get the taper to release. DAMHIKT!

 

[ALEX1952]

Some morse tapers have a tang to resist spinning and to assist the drive, morse tapers are just a very accurate way of holding tooling.

 

[rpf]

Some morse tapers have a tang to resist spinning and to assist the drive, morse tapers are just a very accurate way of holding tooling.

The tang is NOT for driving, it is for removing the taper only!!!

 

[goldstar31]

If you are with the Propositions of Euclid, your Mr Morse used the sine of 10" and a quarter of an inch-- and the bright sparks made a Pig's Ear out of it

 

[ALEX1952]

Incorrect terminology I should have said to help stop it spinning if taper is damaged or dirty.

 

[Shopgeezer]

The tailstock in my new lathe did not have a crossbar in it to engage the tang on the end of the drill chuck taper. I had continuous problems getting the drill chuck seated so I took the tail stock to a machine shop and we installed an offset pin in it. Kept the drill chuck from spinning. I am suspicious of the Morse taper in the tailstock, or taper on the drill chuck arbor. The live centre seems to seat ok but not as much torque on that as drilling.

 

[WOB]

Hi Guys,

The R8 spindle fitting has a locating pin which sits in the groove just above the taper. That pin is there to guide the fitting and the pin stops it rotating in the bore. Very often you find machines with the pin sheared off. A telltale sign that the tool holder has jammed at some point in its life.

On a Bridgeport, many users remove the "locating pin" because it is unnecessary and a PIA when inserting an R8 collet. Mine has been out for many years and I have never had a collet spin in the taper because I always tighten the drawbar properly.

WOB

 

[awake]

The above comments reflect what I have always understood, that the tang in a MT and the pin in an R8 are really just locating devices.

Certainly in my old mill drill, with a #2 morse taper spindle, the various chucks and endmill adapters and such had no tang - it would only get in the way of the draw bar. No problems spinning anything as long as you tightened the draw bar "just enough." As noted above, there were occasional problems when I tightened the drawbar too much - it was the devil to get the MT to release, even beating on the top of the draw bar.

What I was told, long ago, is that if you are depending on the tang (MT) or pin (R8) to actually drive the chuck/collet/whatever, you are fixin' to break something.

 

[Shopgeezer]

To me the tang on the Morse taper arbor is there to prevent it from spinning and ruining the taper In the tailstock. Its not supposed to drive anything, just give you a chance to stop the lathe when you see the drill chuck arbor move.

 

[SmithDoor]

I have a mill with #2 Morse
I use a Tang and a draw bar.
It is 1/4” NC tap in the Tang
The holders that have a 3/8” NC just made thread in Tang with a 1/4” tap hole for the new draw bar.

The holder do not turn
If hard to get out I just a drill drift.

I have drawing and photos here in downloads

Dave

I have an older Jet Mill/Drill with a #3 Morse taper tool holder set-up.
Works very well for me. Only question I have is:
How tight should I tighten the the drawbar to hold the toolholder in?
I know I need not "reef" on it. but how "loose" can it be?
Thank you .

 

[SmithDoor]

Here draw I uploaded in pass showing how fix the slip

https://www.homemodelenginemachinis...2mt-and-r8-w-inch-and-metric-dimension.29445/
Dave

 

[goldstar31]

I recall that many years ago, I had to use a Boxford( a South Bend clone) which had been butchered previously by students. The tail stock poppet was 'scored'
I simply used a No2 Morse taper reamer to clean up the 'mess'

When my lathe( then) had a slip in the tailstock, I simply used a piece of cigarette paper.
Seemingly, no one here mentions such a tool. I regularly use cut strips in my hobby

 

[SmithDoor]

I have same with reamer on lathes.
Back 1970's I purchased used set of morse taper 1-4 .
On my South Bend I keep think making a spare quill with Tang.
I think that slip has around since day one.
Try a BS taper less slip but removing is very hard.
Trying to mill with Tang the holder will drop out.
You see how fix this with last post a combo.
Today using combo it works like R8. and milling machine taper.
Great for small mills.

Dave

FYI
I have had larger mills but hard to fit in small shop and hard to find a small mill with R8.

Today I am working a new shop 10x10 in back yard.

I recall that many years ago, I had to use a Boxford( a South Bend clone) which had been butchered previously by students. The tail stock poppet was 'scored'
I simply used a No2 Morse taper reamer to clean up the 'mess'

When my lathe( then) had a slip in the tailstock, I simply used a piece of cigarette paper.
Seemingly, no one here mentions such a tool. I regularly use cut strips in my hobby

 

[JCSteam]

If you are with the Propositions of Euclid, your Mr Morse used the sine of 10" and a quarter of an inch-- and the bright sparks made a Pig's Ear out of it

Thanks for that I was recently trying to recall the angle of dangle for the Morse tapers, strangly when I looked up the angles, all were Listed on charts as slightly different! but I knew there was a simpler way for rough setting of the tapers. Certainly close enough for me.

Jon

 

[goldstar31]

Dave
I have to explain that I have a very small workshop as I live on the outskirts of the city where land is at a premium almost as expensive as Central London. I have never owned a Boxford and because Myfords offer a wide amount of accessories, that is my choice. Again, I only have a mill/drill.
In any case, I live in the grounds of what was a mebtal hospital- and I don't want my good neighbours to get the wrong idea

Jon,
Thanks but always remember that the logarithm of a number to a given base is the index of the power to which the base must be raised in order to produce the number
again, always remember that the sum/son on the hippopotamus hide is equal to the sons/sums on on the opposite two hides

 

[SmithDoor]

Here is a photo of my mill 16" table
https://groups.io/g/Drillmill
Dave

Dave
I have to explain that I have a very small workshop as I live on the outskirts of the city where land is at a premium almost as expensive as Central London. I have never owned a Boxford and because Myfords offer a wide amount of accessories, that is my choice. Again, I only have a mill/drill.
In any case, I live in the grounds of what was a mebtal hospital- and I don't want my good neighbours to get the wrong idea

Jon,
Thanks but always remember that the logarithm of a number to a given base is the index of the power to which the base must be raised in order to produce the number
again, always remember that the sum/son on the hippopotamus hide is equal to the sons/sums on on the opposite two hides

i