How to cut a 2mm slot in this?

I'm trying to make a replacement slider in aluminium for a fridge door. (The original is plastic and breaks easily.)

It looks like this:

Straightforward enough in a milling machine apart from the 'T' slot at the bottom. The top of the T is 27mm across and the bottom 16.25mm across. The two vertical cuts are both 2mm, and the bars of the T are 5.4mm deep.

I'm not sure how to cut the 2 x 5.4mm side slots. Any suggestions on how to make this please?

Thanks,

Dave

Edit: cat on keyboard!

Edited By SillyOldDuffer on 07/09/2018 17:58:19

How about a custom made cutter similar to a woodruff cutter?

Ed.

Can I suggest an alternative? Make the lower part in two layers - either:

1. A flat top sheet and below it a pair of L shaped pieces. Drill 4 countersunk holes downwards and tap the lower (thicker) pieces for metric screws - size as big as the design will stand.

2. The top sheet with a flange both ends, and a pair of plain lower slabs, drilled upwards and countersunk, with threads in the thick top piece.

Either way - it depends on what is in your scrap box, and how strong (etc) the result needs to be, and how visible the screws will be etc..

Regards - Tim

Edited By Tim Stevens on 07/09/2018 18:23:55

Grind the end off a Tee slot or woodruff cutter until it is 2mm thick, would really only need to be one tooth that was the full thickness so you could grind at a slight angle so the rest has clearance.

Or grind an old large endmill or slot drill to just leave 2mm at the end

If the 2mm slots don't need to be very precise you could try sawing them with a hacksaw.
You could also plane it out in the lathe the same way you would cut a keyway. You could probably make the tool from a circular saw blade or a broken machine hacksaw blade.

Les.

Edited By Les Jones 1 on 07/09/2018 18:44:05

Edited By Les Jones 1 on 07/09/2018 18:45:05

Jason's way would work, but if you've no cutter you can modify - or are prepared to sacrifice - you could try drilling (say) 1,8mm holes parallel to the 16,25mm slot to shift most of the material and then finish with hacksaw and flat Swiss file. I'd suspect it's the 16,25 slot that controls the slide and the 2x5,4 extensions are clearance, but you'll know better from examining whatever fits it.

Another thought is to mill out the middle bit then get some 2mm gauge plate, grind the end to a slight angle and then use a planing action to cut the two 2mm slots

I like Tim's suggestion but it looks as tho the ends would have to be thicker to get some sensible size bolts through.

Failing that how about 4 pieces of stainless silver soldered together

Have done similar using screwed (& glued) on flat sections for the flange over a milled slot.

Best place to start is a careful inspection of how the thing fits and how much space there is for judicious increases in sections to give more space for threads and / or screw heads. On the one I did most of the flange bottom had plenty of clearance so it was easy to accommodate screws and heads. I suspect the section sizes on the original plastic parts are dictated more by moulding considerations than super strength so there is barely enough material to do the job in some places.

I felt it better to drill, thread and trial fit the flat base in one piece before milling out the slot in the main part. Much more to get hold of and far easier to align things. With everything done in situ small errors don't really matter. After milling the slot I refitted the flat base, still in one piece, with adhesive on the join and loctite on the screws. Once the loctite and adhesive had cured I milled out the slot to make two flanges.

Clive

Edited By Clive Foster on 07/09/2018 19:34:10

3D print one in PETG

I take it this is the slider between the real fridge door and the outer decorative cladding.

Where does the thing break?

You seem to have a CAD model of it.

Wouldn´t it be possible to beef it up where necessary, add fillets or make bits thicker and less prone ot breaking and 3D print it? Make it too strong and the next thing to go will be the plastic rail it slides on. I´m sure there are some experts in 3D printing out there,

cut in with an angle grinder arrangement (dremel?) cutter no more than 27 mm in size

At the very least it would do most of the work required

As Clive says inspect where the unit fits to establish if any of the dimensions can be increased to make assembly easier. Fabricate the main part from angle aluminium cut to size and drill/mill slots. Then machine L pieces from solid to create 2 L section pieces with the required 2mm step to generate the gap. Fix 2 L pieces to the prepared angle section using screws/glue or low temp melting aluminium alloy.

Edited By Martin W on 08/09/2018 00:38:23

Edited By Martin W on 08/09/2018 00:40:20

Being ali would a router cutter be up to the job if so look at this cutter Guided Carripile l Cutter

Set it up on an angle plate - or a vertical slide if you have one on your lathes cross slide then mount a 2mm parting off blade in the four jaw chuck and set it horizontally so you can use the carriage to rack work piece onto the tool and use the cross slide to feed the workpiece across . To cut the other side just turn the chuck around 180 deg and feed out .

You can do something similar with the mill but you will need to make a cutter , a piece of silver steel 1/2 round is set up in the mill to machine a flat on each side for a length a little longer than the slot you wish to cut and this leaves a tang of 2mm width ( a square collet block makes this easy as you are really just making a parting tool with a round shank ) once shaped - harden and hone it and the workpiece can be held in the vise or bolted down to the table to perform the cut by using the quill to rack the tool up and down .

You could also make a custom fly cutter if you don't mind grinding up a toolbit for it .

Sounds like a job for one of Ketan's new range of files that just cut on the edges

What part of it breaks?

All replacement parts are available on Amazon or Ebay, I replaced several over the years.

I would think that the Alu would start shaving the plastic runner, the wooden door is held to the fridge door by these runners and any atmospheric difference in pressure as you pull open the fridge door puts a load on the plastic runners. One thing I did was to punch a very small hole in the formed foam seal of the fridge door seal to equalize the air pressure.

Clive

When that becomes a problem with our fridge, it means the drain tube for the auto-defrost needs unblocking.

A suitable tool would be easy enough to make from silver steel, say 15mm in diameter. Turn a shank, possibly 10mm with a 4mm 'neck', then part off to leave a 2mm thick disk.

File to give 'Rufus Roughcut' teeth and harden. Run ad modest speed and gentle feed with plenty of lubrication.

Neil

Edited By Neil Wyatt on 08/09/2018 10:14:06

Could it be folded-up in sheet steel and painted for protection?

Martin.