Cutting Microscope Slide Glass

Hello guys,

I wonder if anyone has any experience in cutting microscopy slide glass?

I have need for four very small pieces of glass approx 12 x 10mm and have been given a couple of slides 40 and 50 thou thick.

I've cut glass before but that was 4mm and I imagine would be far too heavy an approach.

I do have a new, sharp diamond point wheel dresser - though that's mounted in 1/2 diameter mild steel bar - I was thinking that that might be okay despite it's size

Any thoughts, pointers or tips to prevent this shattering into a complete mess would be much appreciated

Regards - Ramon (Tug)

Just lay it on a flat firm surface on top of a piece of plain printer paper. Scribe the surface with a diamond or similar hard point. Lift the slide, place a straight bit of thin solid wire under the scrbed line and press gently down an equal distance either side of the line.

Clean up with a diamond file.

If you want to cut the very thin cover slips try a sharp pair of scissors under water. Have a tray or similar underneaith to catch any fragments.

EDIT,

Second method: Stick to backing block with hot melt glue and cut with a diamond disk in a dremel type tool.

Robert G8RPI.

Edited By Robert Atkinson 2 on 13/11/2020 20:48:46

I recently bought a box of oversize microscope slides 1.1 mm thick. I tried various methods to cut them but found my normal glass cutter worked best. It is a good cutter, bought for leadlighting many years ago. I had no luck with a carbide tip scriber. I broke a lot of slides, but I was prepared for that. Straight lines were fairly easy, but cutting the front cab windows for my Springbok was a challenge. I used a diamond grinder in the drill, wet, to tidy up to final shape. This also had been bought for stained glass. I was very out of practice cutting glass so had to get familiar again, hence lots of broken slides.

Thanks Robert and Simon,

I will approach this with a degree of cautiousness as you suggest.

Interesting to see you found your normal cutter to work best Simon - I had dismissed thoughts of that as being too heavy handed but I shall try the diamond first and keep that as a second option. The diamond is a left over from working days - I can easily reduce the diameter of the holder to a more sensible size at the tip

Thanks again - Tug

A normal (tungsten carbide) wheel cutter should work OK down to about 0.5mm and give clean cuts. (Look after the cutting wheel - any chips out of its edge will be reflected in the glass cut quality).

You may struggle to break off the narrow edge of the slide - it might help to scribe all of the cut lines first (in a # pattern) then break the larger pieces, leaving the narrow edge until last. This avoids the tendency of the cut to run off at the start/end of the scribe line.

You may find that lubricant (white spirit, or similar) helps.

Keep everything clean...

Edit - if you can find a good edge on the diamond, that will work, too, but it does need to be a very sharp point to create a 'vent' in the glass. A worn diamond will scribe a line, but there won't be a vent under it and the glass won't break cleanly.

Edited By Andy Gray 3 on 13/11/2020 23:27:04

Hi Ramon,

If you're going to use the scribe and break method, you may find that spitting on the scribed line (or licking your finger and running it over the line) will help to get a clean break. The glassblower who taught my laboratory practice class recommended this when snapping glass tubing.

Regards,

Alan

Oh yes, for narrow lengths for the side wind shields, I pinched the narrow section in the milling vice jaws with scribe line level with the jaws and snapped. Plenty of scrap, but it only had to work cleanly twice, and I had one hundred slides.

Thanks for this further input guys - much appreciated.

The diamond is unused so should be sharp enough - hopefully! I have a feeling from what Simon is saying that I have very little chance of getting these four pieces out of the one slide!

I don't have them yet - a friend is donating a couple, I'll try with those first but I have a sneaking feeling I may have to get a 'few' more. I'll try Ebay!!

Regards - Ramon

Ramon have a look in charity shops for mounted photographic transparences some of those have glass mounts

way,way back when i was just a lad, i read somewhere that you could cut glass slides for microscopes etc, by using sharp scissors under water - lots of shattered slides and cut fingers, not one cut cleanly as i desired. move on to next project and put it down to experience, ho! hum!

Thanks guys for the further input.

I now have 50 slides and 100 coverslips winging their way via Ebay. Just over 6 quid delivered hopefully I'll get four small windows out of them without to much scrap.

Regards - Ramon

Hello Ramon,

This is a trick I discovered many years ago, it might be worth you trying it again.

Using a good pair of strong scissors, cut the slides underwater, thin sections like microscope slides responded well to the method. Thicker sections tend to squirt out from between the blades

Regards Brian

For some reason old glass does not like cutting cleanly

I had read / heard the same thing (no idea where), but despite an almost unlimited supply of thin glass and repeated attempts, this never resulted in anything other than shattered glass. I would love to see someone actually doing it.

Cutting with a wheel or scribe relies on creating a vent (crack) in the glass surface that propagates through the thickness when that surface is put in tension.

Old glass becomes 'weathered' (even indoors) which both makes it harder to develop that initial crack, and also provides a plethora of microscopic defects which can lead a propagating crack to wander off.

(Sorry for 2nd message - can't seem to find how to include a separate quote).

Guys - I really appreciate all the responses and I've taken note of all. The slides should be here next week and I'll do my best to create said four pieces of 10 x 12 mm. They are for the finishing touches of a latest project which I will share once complete.

I will post how I get on with the glass in case it helps someone else even if it takes most of the box

Regards - Ramon

Hmmm!

I don't have any need or desire to cut microscope slides at the moment but one never knows...

I now see people mentioning cutting glass with scissors. No! No! not possible.

Regards.

David.

Edited By David Colwill on 15/11/2020 13:08:56

I think you'll have to experiment because much depends on the type of glass used to make the slide and how thick it is. Microscope slides are unlikely to be ordinary glass. Good ones meet optical and other standards that imply specialist glass & heat treatments etc.

Never needed to cut slides with my microscopy hat on, but I did it once to repair an electronic display. Succeeded with a cheap nasty slide of the sort supplied with toy microscopes. I don't have a sharp diamond and broke maybe 20 slides getting a satisfactory result.

The cheap slides behaved like soda glass and were easily scratched with carbide. Decent slides made by Chance were found more likely to break, at least in my clumsy paws. My stock proved scratch resistant and unwilling to snap cleanly along a line. They're original Chance Bros slides, perhaps 30 years old, and modern ones could be different.

Dave

Hi guys - as promised an update on trying this for the first time.

When the slides first arrived I had a tentative go on the corner of the bench using the diamond - no luck but a carbide scriber did appear to be an improvement however three shattered slides later and only one piece the size required I decided to put all away until a more controlled approach could be entertained.

Well, setting up on a nice clear bench this afternoon I used the carbide scraper and white spirit as a lube. The glass was laid on about five sheets of plain copy paper for some 'give' under the scriber. Amazingly I got five 8mm wide strips from the one slide and four of these were cut to give the 11.5 mm dimension. I did need to scribe more than once on each but held with the line over the wire after scribing the glass cracked easily under finger pressure.

This is the remaining waste glass

And these are the pieces required along with the receptacles. These are two oil reservoirs for the main bearings on a stationary engine. The glass will be epoxied in place each side

My thanks to everyone who responded to my question including 'br' who offered to do it if I had issues - I took note of what was said and it has proved of great help. No one is more surprised than myself for the low scrap rate today so good on you guys.

Ramon (Tug)

Nice job, Tug, and thanks for keeping us up to date.

George B.