- Aug 18, 2019
I have been wanting / needing a toolrest on my mini metal lathe to enable me to turn wood etc. I sold my Record 1.2m wood lathe last year and bought a cheap Chinese metal turning mini lathe. While I'm fixing a few faults on the lathe I can at least make some stuff too.
As per my other instaructables, I like to make stuff from scrap and as cheaply as possible. This project cost me $10 for a lot more scrap metal than this toolrest needs and the cost of :-
1x 50mm x 30mm round steel bar, - (this could be cut from anything like a large steel bolt etc)
1x 8mm (M8) bolt, washer and nut,
1x 150mm x12mm (M12) steel bolt, and
1x 8mm wing bolt.
I went to a local metal workshop and found a few short 10mm offcuts, in their scrap bin, in widths that I could get some of these parts out of. 10 bucks for a handful of these is not bad.
I considered for quite some time making a toolrest that I could clamp into the quick change toolpost but I decided that a more versatile and more robust rest would be one that could slide and clamp along the lathe bed.
As a toolrest like this needs to come up close to and just below centre height (to rest the chisles on) I planned it out using SketchUp - the drawings are included here.
These images show the design I chose to use. The 1st image shows the assembled rest, but importantly, the lathe centre line and the position of the top of the tool rest. It's important that this rest (the red component) can position close to and just below the centre line of the lathe. Also important is the length of the sliding component (slotted base) so that it allows the rest to position on the centre line AND extended to allow the rest to be used on the outside of large (175mm or 7 inch) discs that could be clamped on the faceplate.
The 2nd image gives a view of how I designed the rectanglular plate under the lathe bed, the bolt and nut tightened on this plate, and the large washer above the lathe bed, the banjo (I'll explain this later), and the ratchet lever clamp.
The 3rd image gives an exploded view of all the components.
Measurements for my lathe size (most sizes are not critical) :-
Rectangular under bed plate -- 50mm x 39.5mm x 6mm (under bed gap is 40mm so 39.5mm is a good size)
Bolt and Nut -- 50mm x 8mm (M8) - - (I used galvonized )
Washer slide on top of the lathe bed -- 63mm x 10mm
Slotted plate for the banjo -- 150mm x 35mm x 10mm
the slot is 100mm x 8mm offset by 18-20mm from one end
Vertical toolrest holder and clamp -- 50mm x 30mm (flattered both sides)
The toorest -- 60mm x 10mm welded to a 90mm x 20mm x 5mm plate
Let me say that the sizes of nearly all the components of this project are non critical. The facing I did in the lathe is only to remove the rust and get the plates flat and fairly square.
Start with what you have. I had a few old brackets that came off a trailer hitch that were about 8mm thick.
As the gap under the lathe bed is 40mm I chose to make a plate 39.5mm wide and about 50mm long. This came out of one of these old brackets perfectly.
Cut these with a 1.5mm x 125mm steel cutting disc in the angle grinder
The first thing I did was to hold the plate on edge in a 4-jaw chuck and flatten off the 4 sides. This might look like dangerous tooling - it is fine as long as you check your cutting gaps before starting the lathe and then working the compound slide in very slowly (about 3-5 indicator positions on the gauge - that's 3x .025mm= .075mm). This is a sort of reverse way of fly cutting. It's intermittent facing until you get close to the centre of the work.
Next. I faced the plate on both sides using my 4-jaw chuck. Having independent jaws is ideal for this work. This little plate, just would not fit nicely centre in the outer jaws as the jaws closed together in the middle leaving a little gap that prevented clamping - so one jaw had to be reversed and, as you can see, the plate has to be off centre. As we are facing the plate this is not important. The thickness of the plate needs to protrude beyond the jaw faces to prevent cutting into the chuck. If the plate is too thin you will need to pack up the back with a large washer or something else.
Once all the faces are done drill a 8mm hole in the centre.
The large washer that slides on top of the lathe bed needs to be thick enough to allow the sliding base of the banjo to clear the raised section of the lathe bed. I chose to make this washer from 10mm plate.
Make the large washer (in the 3-jaw chuck) In the same way as the the plate on the underside except turn it round.
Cut a 65mm square out of some 10mm plate using the angle grinder with the 1.5mm disc. Scribe corner to corner to get the centre and then scribe a circle of 63mm. Now cut the corners off and again cut more points off to get the plate fairly round. Now drill a 8mm hole in the centre. Tighten a 8mm bolt and nut in it and use this in the 3-jaw chuck in the lathe and turn it round to about 63mm. Face off both sides and you have made the upper washer.
I did try a square plate at first but I found that it turns around as you slide the toolrest around on the lathe bed and the corners jamb up against the raised part of the bed. So I decided to make it round and this has no problem - just a bit more work, but it looks nice too.
The second two images show the washer bolted through the bed to the underside plate. You can see in the 3rd image that the bolt is bolted to the under plate with a nut and this nut gives a small gap to the upper washer. This gap is important to allow everything to slide and then be clamped tight to the lathe bed.
The banjo is the name given to the slotted plate and the vertical toolrest clamp. The vertical clamp will eventually be welded to this slotted plate. This is made from some of the 10mm plate.
I first tried to mark out and drill a row of 8mm holes along the centre of the plate but a few of the holes started to offset from the centre line. This was most frustrating as I used a short centre drill to start the holes.
I then chose, what I think is a better method anyway, to use the angle grinder with a 1.5mm steel cutting disc in it. (I would have used this anyway to do the final cuts and clean up the slot).
I love the 1.5mm disc in the grinder for cutting steel. It can easily be used to cut through 12mm (half inch) steel with a fairly accurate cut.
I drilled the two 8mm end holes and then I scribed the 2 slot lines between the holes. Using the 1.5mm disc in the angle grinder (it's a 125mm diameter disc by the way and easily held in one hand if necessary) I cut a starter groove down the two scribed lines and then deepened the cuts until they were through the 10mm plate. Make sure you don't cut into the walls opposite walls of the end holes. (I did nick the opposite walls but I could sort these out with a round file at the end). Clamp the plate at angles so you can access the slot well and cut up and into the end holes. Turn the plate over and, using the partial slots that have come through, do the same until you break through and the centre of the slot comes free. I cleaned up the walls with the disc and checked regularly with a 8mm bolt to see if it moved freely in the slot.
Clean up all the plate edges etc with a file.
Now for the vertical banjo clamp.
I still have a good length of the bar I used for the Fly Cutter project I posted some time ago. However, this vertical clamp can be made possibly from a very large bolt of any other steel material you can find. The diameter of this bar needs to be large enough to give you about 5mm (at least) of thread depth when drilling and tapping the side clamping bolt. The hole through this will be 10mm (what I chose to use) and. I guess could even be drilled off centre in a smaller diameter to give you the needed 5mm thread length.
This bar just needs to be cleaned up and faced on both ends. It will eventually be welded to the end of the slotted slide with the widest gap - slot to end.
Centre drill the bar in the 3-jaw chuck. Then drill right through using first a small drill, increasing in size up to 10mm.
I decided to chamfer the one end. Why? Because it looks nice, and it may help in dropping some shavings that might build up on it when working on the lathe.
Transfer the piece into the 4-jaw chuck and face off two opposite sides. These can be a much or little as you like. I used them to :-
1. Drill 7mm a hole through to the centre. (to be tapped to 8mm - M8)
2. These flat sides I used to help me weld the piece to the slotted plate later.
The vertical clamp
Drill a 7mm hole fairly close to the top of the vertical clamp, in the centre of one of the flat sides. These flat sides make it very easy to drill this hole - it can be done on the bench drill.
NB. Why is this hole near the top end of the vertical clamp? Because if it is too low you could put the toolrest column up above the locking screw when adjusting it for the height you want.
Tap this hole for an 8mm (M8) thread.
It's good practice to use the tap (M8) in the drill press before removing the drilled piece. This will align the tap vertically with the hole.
With the drill SWITCHED OFF pull the tap down into the hole and MANUALLY turn the chuck cutting the start of the thread. After about one or one and a half turns the tap will become tight to turn. You will feel the tap pulling into the hole.
Now loosen the tap from the chuck leaving the tap in the hole and transfer it like this to the bench vise. Continue cutting the thread using the manual tap wrench.
Now let's make the toolrest.
I did not have any 10mm round bar so I bought a 150mm x 12mm steel bolt with a large part of it unthreaded.
I cut the hex head off and I first tried to turn a 10mm bar on the threaded side. I thought with the treads removed I might just get 10mm, but it turned out to be 9.5mm or thereabouts. So I turned the rod around and machined the 10mm from the unthreaded length of the bolt.
We only need about 50mm x 10mm of bar turned so choose whatever suits this length.
I turned it down so that it would be a nice sliding fit in the 10mm clamping hole. 4th image.
Now clamp the slotted plate and the vertical toolrest clamp together. The flat side with the clamping hole to the end of the slotted plate. Remember to have the threaded clamping hole at the top.
Weld a small seam along each flat side.
My welding leaves a lot to be desired and welding small parts like this is not easy.
Now for the final part - The Toolrest
Make up a bit of 5mm plate for the length of the rest you want.
Put the length of 10mm rod your made up into the vertical clamp (all the way to the bottom). Put a thin rod in the chuck and bring the banjo around to place the vertical rod close to the rod in the chuck. Now figure out by sight where to place the 5mm plate to be used as the toolrest. It should be a little lower than the horizontal centre of the rod in the chuck - placed at about 30 degrees.
The 20mm plate I cut just reached the rod in the chuck - you might want to use a wider plate of, say, 25mm or 30mm.
Now mark and cut the vertical 10mm rod at the approx 30 degrees. And weld the plate's centre to the cut off rod. It's a bit tricky trying to hold these together while welding. I used a variety of clamps and wedges to tack it and then finish the weld on both sides.
And here in the final image. Our toolrest is finished.
I had a tin of blue hammer finish paint and painted it. This will help with keeping the rust away.
I'm still deciding whether to use the M8 ratchet lever clamps as I've shown in the SketchUp drawings. It might not be necessary for the vertical toolrest clamp but replacing the nut on the lathe bed clamp might be a good idea. The benefit of these clamps is that you can orientate the handle (lever) wherever you wish after clamping it - to move it out of your way.
I think it looks pretty much like a bought component !
Can't wait to try it out - I'm ordering some pen turning kits and I want to make the mandrel(s) for these kits on the lathe too. I see videos of mandrels being made on a wood turning lathe and it just doesn't look good.
I've run into problems only being allowed 30 images - so I'll have to sort this out in the edit - In the meanwhile I have to go to work.
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