New Member With A Central Machinery 44142 3 In 1 Mill Drill Lathe

[707offroad]

I bought this machine in 2008 and I've added DROs for accuracy. Unfortunately it's lacking rigidity.
I tightened the gibs and it just has more resistance and still deflects and chatters. Is there a special procedure to get these Chinese machines tight?
Also, the endmills work themselves out of the collet and have ruined a couple projects. I's their a remedy to keep the endmills from working loose?




Thanks in advance
-Dave

 

[707offroad]

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[Bob Korves]

Those Asian 3in1 machines are just not very rigid due to their design and being lightly built. You have already tightened the gibs, so that is about all you are going to get out of it. You can use end mill holders to hold your end mills, and then they will not suck out. Your machine has plenty of headroom to accommodate them. I am afraid that the only way to get a rigid machine is to buy one that is already rigid, unless it needs adjusting and/or reconditioning the slides.

 

[707offroad]

Thanks I just ordered a set of R8 endmill holders. I was thinking about making some external guides on the carriage and cross slide to add some rigidity. I've never seen anyone do anything like that and I'm not sure it would even make a difference.

 

[Bob Korves]

The first issue is how narrow the bed of the machine is. That, combined with the leverage from the tall headstock and milling column makes for a flexible machine. I don't know what your space limitations are, but I would consider getting solid, dedicated machines if you can find the room and the money for them. You will be a lot happier with the results.

 

[carlquib]

I started with something similar, a smithy granite 1324. My solution was to use small end mills, 3/8 was the biggest it would take without chatter and that was with a modest depth of cut. I've since graduated to much bigger stand alone machines. I occasionally still use the lathe part of the granite, for small stuff, but I haven't used the mill in ages. There is no comparison between the 600 pound 3 in 1 and my 4000 pound milling machine. ☺ There was another 3 in 1 that had frame supports similar to what I think you are talking about, the shoptask eldorado, if I remember right. You can do some amazing work on a 3 in 1 but I succumbed to the dark side and wanted more.

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[bisonworkshop]

i just bought the harbor freight t5980 mill,drill,lathe combo and i have the same problem. and i dont beleive i will ever make it as ridgid as i would hope, but for all i will ever use it for im fine with it. i am doing videos on bison workshop on my setup and the chainges im making and dro is in the works now. i like the way you have yours setup. good luck with your setup. this is my harbor freight t5980

 

[Happycamper]

I had one and had the same problems. I found that you have to tighten everything down when you're milling. Tighten the table gibs as well as the gibs from the saddle to the frame. Only use your crossfeed for movement of the table. If you have to use the X axis be careful and only conventional milling, no climb milling. Take small cuts. Make sure you're at the correct speed for the diameter mill and material you're cutting. FYI, if you need to take the backlash out of the crossfeed, the crossfeed nuts for the Grizzly three in one work on the HF.

 

[Mad Monty]

I have the Enco version 3in1 and did add a brace that made a real difference. Also found that bracing the base helped - reduces flex in the long arm of the bed. A couple other mods, too: machined a longer column to raise the head, with a motor and screw inside to lift it, and replaced the 3/4 HP AC motors with 2-3 HP DC treadmill pull-outs and speed controls. Added an import 3-axis DRO and quick change tool post, bought heavier vice, also self-centering vice, rotary table. Very happy with all results. Working now on making a reversing gear, maybe solenoid operated, and a couple of limit switches. Love the low speed torque and easy speed adjustability of the DC motors, no more belt swapping so I'm more likely to use the right speed to begin with and adjust it on the fly as need be (even while facing, speed up RPM as move toward center to maintain SFM). Love the DRO - if you know where the tool really is, you can tolerate more play which this level of machine has. The QCT is not only more convenient, but much more rigid. Right now, it mounts to the cross slide so I can only come in at 0 deg but think I can make a go-between to mount it to the compound slide. [tried to take a few pix but they are read because of the background, so made a sketch and included a picture of a brace that inspired mine; note the big-ass c clamp that allows the head to go up and down. I intend to slot one of the pieces and drill and tap the other and bolt them together in a couple of places to increase rigidity.] Oh, another advantage of the DC motors is you can stop them on a dime if you switch them from the power source to a near short circuit - it turns the motor into a generator with a huge short, acts like a really strong brake. I can stop my lathe in 1-2 sec with a typical work loaded.]

 

[707offroad]

Update
The cheap digital caliper style DROs have stopped working and I bought a 3 axis DRO with glass linear scales. I should have the new DRO setup in 1-2 weeks. and hopefully have them installed before december.

The machine is still loose as a $2 hooker but, I have successfully turned out some decent parts on the lathe portion of the machine.

I purchased some large pieces of plate aluminum for fixturing my work closer to the milling spindle. I'm going to drill the aluminum plates to be able to quickly bolt them down to the machine. Hopefully I'll have some pictures to post in the next couple days.