i would think 1 thou runout on the tip of a 4 ” cutter is perfectly acceptable

I’m with the others , it’s fine !

But I do worry about the preoccupation with precision on here, when there has been no observed fault or error measured in the parts made. In industry if the part was right that was what mattered. As an apprentice My lathe was a worn Harrison 10 on which I had to work to .00025″ for a job for RR, 400 of them. On the basis of some opinions on here the machine was only fit for scrap ? When the factory closed I would have been proud to have had it.  Many a fine tune played on an old fiddle ! Noel.

I agree that 0.001 runout is pretty good.  One thing that might improve matters is to blue up the surface plate and check all the collar end faces for flatness.  Blue will show up dings that visual inspection might miss.

Also keep the cutter toward the drive end of the mandrel if you can.  Mid span looks balanced, but is the worst place for a cutter.

I also agree with Noel that the armchair engineer ratio on here is on the high side.

Martin

I’ve tried grinding them on the machine but it didn’t eliminate runout, possibly because with the spindle not rotating the oil film got squeezed out (plain taper bearings). Since I didn’t have a tool and cutter grinder it had to do, and it did well enough.

I would look into why you can’t use a heavier feed and DOC; if the cutter runout is only 0.001 and you can hear an intermittent cut it suggests a very light feed.

Is the rapid feed one of those lever-operated arrangements?

On 10 November 2024 at 22:05 RobCox Said:

Then theres the grinding wheel. It will wear as you grind each successive tooth, however fine the final grind is (thinking of ally oxide wheels here).

I wonder whether you could grind a cutter like you tighten the wheelnuts on a car – crossing diagonally from tooth-to-tooth rather than going round in a circle.

With a conventional grind, the first tooth is off a freshly-dressed wheel and the last tooth, at maximum wheel wear is exactly adjacent it, amplifying the difference.

There must surely be a clearance tolerance between the arbor and cutter or changing the cutter would be difficult.

Same goes for a vertical miller, there’s a runout on the cutter.

You clearly already know this, perhaps you need to consider than the web is also full of liars who claim they can do all sorts of things that they actually can’t just to wind you up.

You could use a diamond coated wheel (not the rubber ones ) wear is tiny.

My drill bit sharpener doesn’t seem to care.

Just wonder if the “rapid feed” is more for a “rapid return” particularly if it needs to be engaged to use the handwheels

A reduction in cutter diameter (reducing No of teeth) would result in a slower feed rate for the same given tooth load which may allow you to turn the handle at a managable speed.

On 12 November 2024 at 08:23 JasonB Said:

Just looking at the L2/L4 on lathes.co.uk I would say that the lever is indeed a fast feed . […]

Nicely demonstrated here:

https://www.suffolksteam.co.uk/astra-model-l4-horizontal-vertical-milling-machine

… a link which I think I have previously provided.

MichaelG.

.

Edit: __ here in Mick’s earlier topic

https://www.model-engineer.co.uk/forums/topic/arc-versatile-milling-vice-mounting/

On 12 November 2024 at 08:56 Mick Bailey Said:

The only practical use I see for the rapid feed is in setting up long work off the DTI where it saves a lot of handwheel twiddling. …

Indeed, but the existence of rapid feed in conjunction with Jason spotting the machine has a high minimum spindle speed makes me wonder what type of work this horizontal mill is designed for?  In my tiny mind, Vertical Mills are good for general purpose whilst Horizontal mills are better for repetition work.  Verticals trade production speed for versatility, whilst horizontals are less versatile but quick at what they do well.  Both can cut a groove along a beam, but if many beams have to be cut a horizontal mill will do the job faster.  They can also do gang-milling, cutting more than one groove in one operation.

The combination of high spindle speed and fast feed lever suggest a mill optimised for churning several copies of the same non-ferrous parts out quickly.  Maybe the discontinuous cutting reported by Mick is due to over-speeding rather than run-out; is the RPM too high for steel?   If so, spinning too fast will wear the cutter out much faster than it having 0.001″ run-out!

Had a quick look for manufacturing tolerances on cutters and found this:

The numbers suggest milling cutters aren’t precisely made, and could be much worse than Mick’s 0.001″.  I guess because the accuracy of the cut is determined by measuring on the job, not by assuming the cutter and machine are both in perfect condition.   They never are!

Interestingly, the off-the-shelf tolerances met by most CNC shops are quite poor – about ±0.005″.   CNC can do considerably better, but it costs more.  Same is true of traditional methods – accuracy and precision are expensive.  Therefore professional designers put considerable effort into avoiding the need for high accuracy, and maybe Model Engineers should do the same.   Parts should be no better than they need to be!

Dave