I have a couple questions

[tominboise]

I got a PM728 back in April and have done some projects on it. I am still learning and getting my feet wet, of course, but so far I still have all my fingers and I haven't broken anything yet. Anyway, a couple questions. First, how often, if ever, do you guys pull your milling vises off to clean the chips out out the table slots? Do you just leave it and don't worry about it?
Second, the motor on the x axis table feed gets pretty hot when I am using it. Is this normal? I realize that I am making it do work when I am running a long piece and chamfering the corner so it might be normal.
Third, I get a lot of vibration and noise when I am taking what I don't think are really heavy cuts. For example, I am chamfering a long piece of A36 angle iron, basically cutting to a .250" width on the angle, using a single insert chamfering bit and it seems like if take heavier cuts than 0.003", it shakes the hell out of everything. I could put more weight in my cabinet, I suppose.

 

[Nutfarmer]

don’t blow chips off the mill. They will end up where they will cause a problem. Some manufacturers will void a warranty if a blow gun is used to clean a machine. A brush works well or a shop vacuum. I made a sheet metal tee slot cleaner that just fits the tee slot to clean out the tee slots. When you mount a vise put a thin coat of oil under it to avoid any corrosion. Before mounting anything like a vice or rotory table lightly stone the table to remove any high spots or dings. Above all have fun making new things

 

[Eddyde]

I never remove the vise unless I have to for a set up.
The Vibration and noise is called chatter It could be the the result of, improper feed rate, depth of cut, spindle speed, or feed direction (Climb milling vs conventional milling). Any or all can cause chatter. Also note, spindle or feed speed, can be too fast or too slow, though usually too fast.

 

[GeneT45]

I leave my vise on the table until I need to remove it to use the rotary table, add the rotating base, or clamp directly to the table. Chips under the vise aren't hurting anything.

My power feed doesn't get hot that I've noticed, but I have a different machine than you.

If you're cutting a long piece (as in longer than your vise is wide) it's going to need some extra support or it will positively make a racket when you're cutting. Those single-insert tools make matters worse as it's hard to feed slow enough to keep the chip-load down. Remove the vise and clamp your work directly to the table, or add supports to the outboard side. Consider turning up the speed on your spindle, or using a multi-flute tool.

HTH,

GsT

 

[ChazzC]

How “long,” wide & thick a piece of A36? And how much are the ends of the stock sticking out of the vise? As noted by @GeneT45 unsupported stock will vibrate.

Is your vise on a swivel base? The vise will be more stable if mounted directly to the table. Most of us who purchased a vise with a swivel base don’t know where the base is; a swivel base sounds like a good idea, but it reduces available Z- height and is rarely if ever needed.

With regard to removing the vise, I haven’t removed my vise for at least 2-1/2 years, probably more; I have it mounted off-center on the table so there is room for the rotary or tilt tables, or to clamps items directly to the table (or a reasonably large fixture plate):


The slots are filled with PVC "wood" to keep them clean (they don't make inserts for Mini-Mill tables), and I can reach both ends of a 6" bar centered on the chuck. Using a machinist jack, I have successfully milled parts that were 220mm long:


Overall part was 300mm, but only needed to cleanup the first 220mm; swapped the ends and milled the steps in the un-milled end as a separate setup (also used a jack to stabilize the legs of the channel, and "Yes," I should have changed to a sorter end mill to clean up the legs and slots, but saved a couple of tool changes and did not get any chatter on the thin sections using the 3/4" x 4" CL end mill):



If you look closely, there is a dimple (stoned flush & smooth to the table) to locate the center of the 4" rotary table so I can reach all points:



Most of my work is held in the vise, so I'm not worried about the table sagging since the weight is normally is fully supported over the Saddle & Base.


Oh, I found the swivel base:




Trying to be helpful, so I'm sorry if this came across harsh – keep asking questions!


Charlie

 

[Weldingrod1]

Mounting off center is an interesting idea! It also moves the main wear point out of the middle. You may want to switch left/right once in a while!

I may have to use that trick!

I love the idea of the centering mark too, though I, um, haven't actually USED my rotary table since I built it...

Sent from my SM-S911U using Tapatalk

 

[tominboise]

I appreciate the feedback thus far. I too, removed the swivel base from my vise before mounting it and stored it in the cabinet. The vise is mounted offset to the right side.

The angle as A36 3X3x1/4", 45" long. I am clamping in my vise and using some quasi machinist jack on each end to support it, although it is not a rigid set up. I have to cut this in three set ups due to the length but the precision required is low, so it's not a big deal to get it located using the vise. I don't mill past the screw jacks on either end.

 

[mmcmdl]

I'm one who loves spending other people's $$$$$$ . Buy a matched set of Kurts !

 

[Weldingrod1]

That's a well thought out setup!

You can quiet it down some by C-clamping a stick of something to the back of it. Even wood

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[RaisedByWolves]

That's a well thought out setup!

You can quiet it down some by C-clamping a stick of something to the back of it. Even wood

Sent from my SM-S911U using Tapatalk

Even just adding a clamp for more mass works fine.

Hints and Tips

I had mentioned this earlier and had some people inquire as to what I was describing regarding Allen wrenches and pipes, where I cut a notch for the wrench to rest in to help control it when tightening or loosening bolts. Well today I needed to use this and took some pics. Pipe. Pipe...

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