Thread: building a lathe for woodturning

It has been a while. I have been working on the oval turning set up for the lathe. I had a hard time deciding how I wanted to adjust the belt tension on the timing belts. I went back and forth about six times. Finally I decided to include one eccentric on the spindle mount and one on the final bearing assembly. I enjoy challenges! here are some jpg’s of the solid model. I have made some of the parts. The total displacement is about 11 inches. The second ring of holes on the shift bar is for counterbalancing. I could completely counterbalance the assembly for turning each piece but I think I will do more milling instead at speeds of less than 60 RPM. with the swing arm set for large turnings I am sure it will still be pretty unnerving. so here is an update.
finalside.jpg
the large plate with the rounded ends is fixed directly to the spindle. this drives the idler shaft around the fixed sprocket. the ratio is one to one. since the idler is driven by the fixed sprocket this sections “synchronous” with the rotation of the spindle. the idler is attached to the final with another timing belt. This section of the drive is two to one. As the spindle goes through two full rotations the final drive only makes one full revolution. since the final drive is off center it moves in and away in its trip around the center but the work only makes one half a revolution. So it makes one side of the oval on one revolution of the spindle and then cuts the other side the next time around.
final front.jpg
the sprocket to the left is an index ring it can either be locked in place or rotated while the turning is being made it carries the fixed drive sprocket….just thought I would throw it in.
finalfrontopen.jpg

partial bed down the line.jpgpartial bed angled.jpg
I worked on the bed some today. It’s al welded and bolted together. I still need to add the cross feed rail. It is a piece of heavy angle the will go in the front. I will keep the old atlas for two ok threereasons. one I can put it on the 8” I beam and use the VFD to drive it. Two I can use the same familiar setups for some production runs. OH! and three I can use it as an extension letting me turn up to 14’ between centers by turning half at a time.

just warming it up for the weekend! hope to hear from ya soon!

I love beasts, and this sure seems to fit that description!!!

Very good looking build!!!

I have been following this thread with interest.

Just a few observations if I may. Bear in mind that these are my personal opinions for what they are worth.

I think that the headstock will need further bracing to avoid torsional twisting around the centre point. There is a lot of hardware hanging off it, e.g. motor and headstock extension in relation to the mounting footprint.

The next problem could be the amount of "leverage" it has off the headstock end of the bed. The pictures don't show whether there is bracing supporting it.

I would be very wary of putting something big and unbalanced on it.

I guess we will have to see. I have room for reinforcements if I need to. here is a shot of the tailstock and one of the underside of the headstock. the baseplate on the headstock is 1/2" and the base that it all rests on is 3/4". there is a central bolt to hold it in place when I turn it and four 1/2" bolts to lock it in place when I get there. the gussets are 1/2" as well 7018 rod for most of it and I had a couple 11018 for root passes.

tailheadstock.jpg

underside headstock.jpg

The main I beam is o the right of this picture and as you can see in the top the gusset runs to the bottom of the beam. the gussets are both attached to the web of the I beams for the most attatchment area. I am very happy with the outcome. I have .003 runout across the mount plate and the column base was machined perpendicular after welding so it is pretty true.

Now that I have seen the whole lathe there are a few more points.

The tail stock base needs to cover the whole of the bed or at least extend past the webs of the "I" beam or it will definitely flex under load and twist the flanges.

It also needs to be extended in length to counteract the leverage when you tighten it against the timber.

The legs also need to be braced in all directions to stop any movement.

Thanks Robo. if the need arises I can extend a pad behind the main box of the tailstock stand. The lathe I have used for long turnings in the past used the headstock off a 10" atlas lathe. It was fastned to a much larger machine bed. the headstock riser wa a peice of 6" "I" beam with a 3/16 flange notched and filed to match the piramedal way. it was held in place with a single piece of 1/2" all thread. the flange on the large I beam is 1/2" inch and the flange on the small one is 3/8". I will check test it by putting a short piece between the centers and pushing in the spur and center. If I lay a straight edge against the base vertically I should see the flex way before I hurt the ways. As the end lifts off the bed. I can always make the extension shoe and the draw pad wider. Thanks for the points to ponder! Did the attachment of the headstock platform set your mind at ease? there is a shelf under the lathe bed that splits the leg length in half. it is made of 4" channel and also welded to the legs to stiffen them up. I have four spare 2 hp motors and several other heavy peices of tooling stored here to hold it steady to the floor! there is a drawer for tooling just under the bed also full of tool holders, centers, small templates, etc.

Had a great day in the shop today working on the lathe! I got the VFD mounted wired and programed! I also built a remote station for speed control, start and stop and four preset speeds. I worked on the longitudinal feed too. Works great! I still have to guide the back end of the cross feed and mount a tool but hopefully I can get something off it over the weekend. I'll post some pictures.

home made lathe for large unique wood turnings - YouTube

Maybe this will get your juices flowing!

A seriously good beast there,oreos!!!!