Tool Grinding Guide
Groover/Mini-Parting Tool: - Cost $0
I use this tool to make circlip grooves & it has worked as a parting tool for bar up to about 15mm diameter.
This was completely made from scrap steel offcuts. The section for clamping in the toolholder is about 2-1/2" x 3/4" x 1/2". The backing plate is 1" x 1/4" held on with 4 countersunk machine screws. The clamping plate is 1" x 1/8". 6 small bolts from an old Suzuki engine holding it on. A broken hacksaw blade is also needed.
The large block & the backing plate are shown held together with 4 countersunk head machine screws (& Loctite for added security). Notice that they are joined in such a way that the cutting tip faces upwards by 5-degrees when in use. If I want any angle of back-rake other than 5-degrees, I can always regrind the top of the hacksaw blade. I usually give the cutting tip a small front clearance, but with this degree of back rake you have to be careful not to give too much as it is easy to make it dig in & break the tip off.
The grooving tool uses a reground hacksaw blade as the cutting tip. The blade is held in place by a cover plate with 6 machine bolts.
The broken hacksaw blade has it's teeth ground off, making it about 2mm narrower than it was originally. Remember that a hacksaw blade is only about 25-thou thick, less than 1/32", so you can't be 'ham fisted' with it.
Along the backing plate is a shallow slot machined to a depth of half the thickness of the hacksaw blade, for the blade to sit into. The milling of this slot was done by bolting the backing plate onto the cross-slide's angle plate. The milling tool was a broken 1/4" H.S.S. twist drill reground to function as an end mill, held in the 3-jaw chuck. Milling took 2 passes with the work moved on the angle plate between each pass - how I looked forward to having a milling machine to simplify jobs like this. Still, it proves how little tooling/machinery you really need.
Fly-Cutter: Cost $0
For bolting onto the faceplate.
This was completely made from scrap steel offcuts. The section for clamping on the faceplate is about 7" x 3/4" x 1/2". 2 small bolts from an old Suzuki engine holds it to the faceplate. The H.S.S. is the shank of a broken 1/4" drill shaft, held in place by a 1/4" grubscrew from an old Singer sewing machine.
The cutting tip exits the main toolholder at a 45-degree angle to give maximum fly-cutting diameter.
When machining large surfaces, the fly-cutting is done at the slower speeds of the lathe, making sure the tip is set up to clear the saddle on rotation.
Wobbler: Cost $0
The Wobbler is a device for centring work about a specific location or point while held in the 4-jaw chuck or on the faceplate, prior to further machining.
This item was made totally from scrap materials. The long bar is a shaft removed from an old inkjet printer with a 'pin' brazed into it at the point of attachment in the gimbals. The gimbals and upright tube are removed from an old turntable, they were originally the tone-arm which holds the stylus. This tube is threaded to take a bolt which has had its head ground to fit in the tee-slot of the saddle, the washer & nut just clamp the unit down & stabilise it.
Because one end of the shaft is longer than the other, it provides amplification of the error from centre.
The unit does not have to be centred exactly as it is the relative movements of the end that are important, not it's absolute position. So while it is ideal to have the point on the long end of the shaft line up with the centre in the tailstock, it's not overly important.