Tag Archives: Optimum

New Optimum S 122 G Bandsaw and a Hack

I recently got a bandsaw, to be able to cut stock for general use and big steel square tubings for the future DIY lathe stand quickly. So, I got an Optimum S 122 G (which was within my price / performance range). I’m not even going to start about the problems I had while buying it (welcome to Turkey, where no one gives a shit about customers post-sale).

Optimum S 122 G

This one looked suitable for my needs.

This video had all the help I needed to be able to align the saw blade. Ghostses even kindly responded my question in detail. Yet, something was wrong, and I couldn’t get decent cuts for the life of me.

At the end of each cut, I kept finding the one side of the blade making an angle from the stock, while the other side was square (and when on rest, the blade was dead square to the vise, I used parallel bars and an angle ruler). I kept getting cuts with a vertical angle, with more material at the bottom.

Crooked Blade

This was always what I had. One side of the blade at angle.

10mm Silver Steel

10mm silver steel after a bad cut.

I soon realized that, when I pushed the main saw part when it was all the way down, the hinge shaft was actually moving about 1mm up and right in one of its holes (also moving the blade away from stock). All was good when it was all the way up, due to weight on that part pushing the shaft down. Right after that, I still wanted to try and cut some 60 mm x 60 mm box tubing with 3mm wall thickness for the lathe stand, and I broke the blade, probably due to excess speed. I left the shop for a while not to stress anymore over it.

So, I came back after an hour or so and disassembled the saw to be able to reach the angle plate on the saw stand with no fear, since dealing with machines is easier than dealing with shifty sellers here.

Saw Hung

I hung up the main body where my punching bag used to be, since my back (thanks to lumbar disc herniation) can no longer handle such weights. Gone are the days when I could lift 50kg boxes.

Saw Wheels

A closer look at the main wheel assembly.

I drilled and tapped M6 screw holes in both base plates of the hinge right above the gap (piece of cake on this cheap cast iron), screwed in cone point setscrews (better angular pressure for what I needed) and stabilized them with non-permanent Loctite clone. The resulting motion was very smooth.

5mm Drill Hole

Drilling this porous cast iron was very easy with the good quality bits I recently got.

Tapping Second Hole

Using the milling machine as a guide for the tap wrench. The angle looks wrong, but it’s due to lens curve.

Tapping End Close

The cast iron was so soft, it was a piece of cake to tap it with this HSS tap. Looks crooked again. See how the hole looks warped? Also see how they failed to center the drill at first attempt…

Tap SS Hole

The resulting hole was rather nice and functional.

SS Clean Stick

I first cleaned the holes from grease with brake pad cleaner, then applied Loctite clone to stabilize the setscrews.

Setscrew In

Testing the first hole with a longer cone point setscrew.

Setscrews Shaft

I left it to cure overnight, after wiping off the excess.

Eventually, I ordered two 14 TPI blades and one 24 TPI blade yesterday. The saw will be sitting in the shop until I receive them. Projects on pause as well. I also removed, cleaned,  and re-mounted the lathe chuck. The runout is now down to 0.01 mm.

New Optimum D250x550 Lathe

I finally got a lathe! I have been wanting to get one for so many years, but I got a milling machine first, also useful as a drill press. They didn’t have a DC Vario in stock. I wanted it because it had a pot + pwm driven 1.1kW universal motor on it (I was doubting its power though), later on I realized ac induction motors have a higher power factor (and no brushes!), and this 750W motor is really powerful. I can always get an even more powerful AC motor for real cheap, too. Although I’ve got some amateur workshop experience, I’m a noob when it comes to the lathe. I’ve read a bunch on it in the past, and watched many videos, but practice is something else. Here’s a video of my first cuts on 6013 aluminium and silver steel (1.2210), using 10mm brazed carbide tools. The tail stock still needs to be aligned (sideways done perfectly… now the height… but it’s 0.125 mm high?), the chuck is also 0.06 mm off. The video has the necessary explanations in the comments section. No, I can neither find, nor afford a true German, American, Japanese, or British lathe.

Lathe Bench

I need a lathe stand!

Here’s how I measured the chuck and the tailstock alignment, individually and in sync. They were at (negative) max at the same spot (I can’t guarantee that the regular indicator was right above the center, but the chuck’s runout last a bit longer, probably due to indicator sensitivity difference?), which tells me the chuck’s runout adds to the tailstock’s. When the chuck is lowest, the tailstock’s dead center is highest. So the chuck is 0.06 mm off, and the tailstock is actually 0.065 mm off. I need to go down to 0.01 mm!


Both indicators are reset when the DTI’s  (we call it a run out indicator in Turkish, the other one is just an indicator) body is pointing up.

Both indicators are at max.

Both indicators are at (negative) max. Zoom in for the mirror.

Induction Hardened

Even though this a German lathe made in China, this makes me feel better about it. Smaller models don’t have this.

I’ve been working on (and off) a mini table saw and an arcade console in the past couple of months, but mostly being lazy. I’ve also been lazy with the blog, but the projects are coming soon. I need to cleanup the workshop first. I also started stocking up some metal for future projects. Here are some 6013 aluminium, silver steel, and regular steel (the 2mm bunch. I thought ordered 1m and got 1kg. It was my mistake, the price was so good) rods and a package of brass,  7075 aluminium, and polyamide rods and bars from my friend Murat in İzmir.

Metal Stock

More on the way 😉 Find the cup holder…

Some parts I turned later on for a test. The 5.98 mm stainless steel rod slides smoothly, without much play in the aluminium part, drilled and reamed to 6.00 mm (not sure,  can’t measure correctly). The 6.00 mm shaft I made from silver steel is a tight fit for this hole.

Parts 2

A sliding fit.

parts 1

A tight fit.

I also got a sine vise last month. It’s my little treasure 🙂

Sine Vise

Finally I can cut angles. 0.005 mm tolerance in 100mm.


Sine vise, new digital caliper with ABS function, and a cheap DTI from China.

Update: As these two sources indicate, it’s ok for the tailstock to be 2-3 thousandths (damn imperial) high above the headstock’s center, which is 0.0508 – 0.0762 mm. They make them that way,  so it levels itself when its bottom wears off over time, or the weight of the workpiece pulls it down a bit. There’s also some discussion about indicator sagging due to weight.



Here are some pictures from the recent projects…

Full Plate Belts

A 90 mm x 6 mm breakthrough slot for the circular blade, and a 6 mm deep full t-slot (neck is 10 mm, t is 14 mm wide) for the protractor guide.

Wood Nut

Wood nuts used on 10 mm plywood for mounting the metal brackets to the arcade console.

And here’s the stand I designed for the lathe. Lathe model is taken from the 3D Warehouse and stretched to fit.

Lathe Stand

I don’t have enough sheet metal to cover the whole thing. So the list covers only what I got.

Optimum BF20L Motor Brush Problems

As I wrote in my previous posts, the brushes of the motor are gone, and I need to get a pair or more soon. So, I decided to remove the motor in the mean time. Here are some pictures of the motor and the mill during the disassembling process.

Motor Off Top

Top of the mill after I removed the motor and cleaned the grease with break pad cleaner.

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