Stiffening A Mini Lathe Bed

I haven't yet. Life has gotten in the way. I have only gotten as far as taking all dimensions from both my lathe and donor bed. They should match up height wise with just a slight bit of milling on the donor and adding a foot plate at the mounting end. I had to stop there as I had to go through my drill press because it wasn't milling too good. Still isn't perfect so I was hesitant to do any milling on the lathes. Then life got in the way. But will be getting back to it soon. ( I hope )

I would suggest a stiffening frame be made as a box girder, a simple plate is way too flexible, and both beds aligned and firmly attached to it. If you can get you hands on a laser gun sight or something similar to align every thing up. The better you get this alignment the better the whole thing will be. Do you have any mates with some engineering skills that can help with the box girder? Over design will be better than under design in this case.

And I'm thinking my desire to make and fit a vertical spindle mill head to a much larger and stiffer lathe is ambitious.

Good luck.
 
Bob,
I appreciate your input. I was a special machine designer for 10 years and a machine builder for 5 years before that. So I picked up a bit of knowledge and feel I can do the job right with the proper equipment. I am only interested in making the lathe longer not add a milling head. Also I do not plan on over designing to the point of making this become a major change as it would then be better to just get a larger lathe. My goal is to make it a workable longer lathe with as little expenditure as possible.
 
Bob,
I appreciate your input. I was a special machine designer for 10 years and a machine builder for 5 years before that. So I picked up a bit of knowledge and feel I can do the job right with the proper equipment. I am only interested in making the lathe longer not add a milling head. Also I do not plan on over designing to the point of making this become a major change as it would then be better to just get a larger lathe. My goal is to make it a workable longer lathe with as little expenditure as possible.

Obviously you don't need any advice, I didn't realise you had that experience I thought you were looking for advice. However if you have that training, can you please advise me how to build a vertical spindle mill attachment for a 12" x 16" lathe, I think I've got the fame worked out, but would appreciate some advice on building the spindle..
 
Do you just need advice on the spindle itself or the whole project ?
There are a few things to consider for the spindle. Like what type of collet system you want to use. amount of travel for the Quill. Speeds to run at. What machines and equipment you have to work with. Exactly what make and model of machine you wish to mount this to.
 
Do you just need advice on the spindle itself or the whole project ?
There are a few things to consider for the spindle. Like what type of collet system you want to use. amount of travel for the Quill. Speeds to run at. What machines and equipment you have to work with. Exactly what make and model of machine you wish to mount this to.

Thanks for your reply Bill, Sorry for the delay in getting back to you, but I've been away for a few days.

The lathe I intend to mount the milling spindle on is a Liang Dei LD 1216 GH. this is a Taiwanese made machine. The local distributor here in Australia assures me they are very good quality, they claim to have just supplied half a dozen of them to their local trade school in Melbourne, I'm about 500 m. west of there in Adelaide. I'm hoping to have my new lathe delivered in about a month.The only other tools I have is a 7"and 5"angle grinders, a couple of cordless drills, a very cheap and poor quality chinese bench mount drill press, barely able to drill a decent hole let alone any milling.

This lathe is rather short for it's size because I don't have much room, and certainly none for any other machines, so I'm going to have to do everything on it, hence the desire to make a vertical spindle milling attachment. The cast iron bed is quite solid 190 mm (7.5"wide) with good depth.

The cross slide has a power feed travel of 170 mm 6.75". The compound slide has a travel of 90 mm 3.5" if I need to use although I prefer not too , as I feel it will compromise rigidity.

It is my intention to make a strong plate that will clamp to the bed in a similar way to the tailstock with a sturdy column welded on it, this will support the spindle which will extend out over the cross slide about 6" from the column. The mounting plate will have a "V"groove to locate on the front V of the bed and a foot to fit on the rear flat of the bed, this should give it stability and location.

The spindle will locate on the column by bolting two plates (say 6 mm thick) together on is welded to the column and the other will be welded to the outer part of the spindle assembly. this will allow me to adjust the height of the spindle collet. above the cross slide, from 4"to 12"in 4 " steps, I'm thinking of using ER 20 collet system. The collets will be held in the spindle by a conventional draw bar.

The spindle assembly itself I'm thinking along the lines of using a 90 x 100 mm steel tube with a 80 x 90 tube machined to fit inside it. The inner tube will have a roller bearing for radial forces and a taper roller for axial forces at the collet end and a ball bearing at the top end. The spindle will run in these bearings. The top end of the spindle will have a spline to carry a pulley for a belt drive from the lathe main shaft, and by using a 2:1 step up I'll have 12 speeds from 140 to 3000 RPM. Obliviously I will, need different belt lengths when changing the set height of the head.

The inner tube will have a rack cut in it to mesh with a pinion on the height adjustment for the spindle, I'll also have a slot to take a length of key steel to fit in a matching slot on the outer tube. The slot in the outer tube will go right through so that with a clamping screw I can adjust the tightness on the inner tube.

I would appreciate any advice on the project particularly if you think I'm heading in the wrong direction.

Thanks again,

Bob.
 
I can somewhat visualize what you are attempting. It should work for light milling. But you might have trouble getting anything square enough to holding any close tolerances.
 
I can somewhat visualize what you are attempting. It should work for light milling. But you might have trouble getting anything square enough to holding any close tolerances.

Thanks Bill,

I realise that I will have to take light cuts as with all milling on a lathe. As a special machine designer do you see any parts of my concept that I could consider doing in a better way, please advise.

Bob.
 
As long as it is built strong enough and clamps down tight enough I see no problem.

That's the plan build it strong and rigid and clamp tight to bed.

I hope to start building it in about a month when I'm expecting my new lathe to be delivered, I will post photos.
 
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