Glass cutting, with what???

Updated 2022-06-24

 

I've been looking for glass cutters. 

There seems to be two types on the market, roller tipped and diamond tipped. The majority are roller tipped but I was biased against them since I used  an old, diamond tipped cutter borrowed from a friend. It was so much better than the roller cutters I had tried. I've got one of these, donated by another friend but, sadly, the diamond was too worn.

Reading the reviews of different cutters I found two types, strikingly different. One and the same cutter got a lot of positive reviews and a few that said it was royal crap. It seemed that the users that failed hadn't found the right way to use them.

One thing to be wary about: Many (most?) of them are said to be diamond tipped. This is BS. They are overwhelmingly roller tipped with a tungsten carbide wheel. Hard, but not as hard as a diamond. 

How to separate the diamond tipped from the others?

If they have a lubrication mechanism they are of the roller type. If they do not have lubrication you must have a look the tip yourself.

I bought one of each, the diamond tipped here: 

https://www.amazon.co.uk/s?k=glass+cutter&ref=nb_sb_noss_1 

and the roller tipped here

https://www.amazon.co.uk/Silberschnitt-Special-Glass-Cutter-2000/dp/B07CCMCM2R/ref=sr_1_56?dchild=1&keywords=glass+cutter&qid=1600090348&sr=8-56

The roller tipped was rather easy to use but I had to apply distinctive pressure when cutting. I oiled the wheel before use, I think this is much neater than buying oil and relying on a oiling mechanism that will sooner or later will fail. To me automatic oiling seems like unnecessary cluttering a simple tool. 

The problem I experienced was with the diamond tipped. It had got some rather devastating user reviews. Examples:

A) "This product is "Total Rubbish". I know there were several reviews which said this but I chose to ignore them because its easy to blame the tool when in fact you do not know how to use it.

In this case I am saddened to say they were all RIGHT. Draper should be ashamed of themselves for selling such rubbish. Bet it was made in China.

Will not be buying any more of their "Tools"!

Have brought a wheeled glass cutter. Its excellent, job done so no need for this very poor tool. Its going in the "BIN"."

B) "I chose this product as it was a known brand, however after applying any kind of pressure (not even enough to score the glass) the handle snapped off at the brass fitting, which is much narrower than the handle."

So, what was it that was so problematic? Reflecting on how the latter is designed, like a wooden pen, with the grip rather high up, one could surmise high pressure is not what makes it work. The roller cutter on the other hand sturdy plastic handle with a grip near the head that serves as support for, maybe, a higher pressure.

True enough, after cutting for a while with the roller cutter and turning to the diamond one, every cut failed. Period.

I tested to apply less an less pressure and at last the cuts were clean and straight.

It seemed very sensitive to too much pressure, leaving small breaks in the tracks sides that made the break go anywhere but straight. At last I made very light and rather quick cuts, hardly leaving any trace in the glass and then breaking succeeded. 

The handling was very different when comparing these two tools. After I finished my testing, I sat down for a while and thought about which one I'd like to use in the future.

I settled fort he diamond tipped. The breaks were cleaner, it was fast and easy to use, once I had understood how it worked.

But: if you're used to the roller tipped type, changing to the diamond tipped is not easy.

The tools

Note the gleam from the diamond on the
right one (tiny brighter dot)

The upper cut is made w. the roller tip, the lower
w. the diamond tip. The lower is cleaner.  

Update:

I'v tested another glass cutter with much better results:

The cutter head is marked "TOYO TC-17VV"

https://www.amazon.co.uk/TOYO-Oil-Glass-Cutter-Cutting/dp/B00439LAE4/ref=sr_1_57?crid=FD65G5L9IPPX&keywords=glass+cutter&qid=1656061597&sprefix=glass+cutter%2Caps%2C97&sr=8-57

The cuts are barely visible, still breaking cleanly. 

The critical point is when you start the cut. I worked best if I set the tool with the cutting wheel resting against the edge (not on top of the glass), applied the pressure and then draw the line, rolling the tool up on the glass surface.

If the pressure is too light in the beginning of the cut, the break will veer away:

So far, this tool is the best one though not as good as an old fashioned tool with a diamond. There are used diamond ones around but buying them is a lottery. Sellers see them as antiquities and set the price according to that fantasy.