How to cut a 2mm slot in this?

[SillyOldDufferModerator @sillyoldduffer]

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

[SillyOldDufferModerator @sillyoldduffer]

[Ed DuffnerParticipant @edduffner79357]

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

Ed.

[Tim StevensParticipant @timstevens64731]

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

[JasonBModerator @jasonb]

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

[Les Jones 1Participant @lesjones1]

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

[Mick B1Participant @mickb1]

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 2×5,4 extensions are clearance, but you'll know better from examining whatever fits it.

[JasonBModerator @jasonb]

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

[duncan webster 1Participant @duncanwebster1]

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

[Clive FosterParticipant @clivefoster55965]

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

[Neil WyattModerator @neilwyatt]

3D print one in PETG

[Dick HParticipant @dickh]

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,

[Ady1Participant @ady1]

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

[Martin WParticipant @martinw]

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

[DalboyParticipant @dalboy]

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

[I.M. OUTAHEREParticipant @i-m-outahere]

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 .

[JasonBModerator @jasonb]

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

[Gary WoodingParticipant @garywooding25363]

What part of it breaks?

[Clive HartlandParticipant @clivehartland94829]

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

[Neil WyattModerator @neilwyatt]

Posted by Clive Hartland on 08/09/2018 08:05:54:

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

[blowlampParticipant @blowlamp]

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

Martin.

[Ian S CParticipant @iansc]

I have a cutter by CK Zenzes (? spelling) in among'st Dads wood working gear, it's like a little slitting saw welded on a 1/4" shank, I'v also made one similar by brazing a shank on the middle of the side of a bit of a broken industrial 12" hacksaw blade, and forming a tooth on opposite corners. Both these would work on aluminium.

Ian S C

[Adam MaraParticipant @adammara]

I have an old used cutter for a key cutting machine, unfortunately its 32mm diameter and 1.3mm thick, any use? Photo of new one!

[Mike PooleParticipant @mikepoole82104]

It looks as if you will have to make or customise a milling cutter but it may be less trouble to fabricate the tee slot and I think I would rivet it together with countersunk rivets.

Mike

[SillyOldDufferModerator @sillyoldduffer]

I love asking questions on this forum. Experts sort out out my problem while I'm boozing at a family jolly.

Bit more background, Dick and Clive H identify the component, and with Gary are all thanked for focusing my attention on why it keeps failing!

The fridge/freezer belongs to my sister and is fitted in a cupboard. The fridge is on top and its door is joined top and bottom to the cupboard via slider rails. It is the lower component that breaks – they last about a year. The cupboard door has a hand grip running along the lower edge that people naturally use but it puts most of strain on one flimsy part, which eventually breaks. The close-up shows how thin the part is where it connects to the slider! (Bottle-top for scale)

Clive F's comments about 'barely enough material to do the job' and clearance are very relevant. It may be possible to beef the part up, though Clive H is right to worry about breaking the slide rail which is also flimsy, and he's likely right about the vacuum as well. More investigation needed.

For solutions, I'm spoilt for choice:

• Modify an existing tool like a woodruff cutter (Ed, Jason)
• Make a tool (Neil's Rufus Roughcut & Ian's butchered hacksaw blade)
• Misuse a tool ( Derek's router bit & Adam's key cutter.)
• Plane the slots (Jason & XD351)
• Hacksaw slots(Les & Mick)
• Make in layers & glue, screw, or solder ( Tim, Duncan & Clive F)
• Fold from metal (Blowlamp) – possibly how the part would have been made before plastics.

What happens next depends on what's in my junk box: a Rufus Roughcut or fly-cutter most likely.

Special Mention in Dispatches for Neil's 3D printer. I thought this was a good idea but it turns out my kids are unhappy about me blowing their inheritance on 'toys'. Put to me vigorously that a man with a garage full of tools should be able to fix a fridge door with what he already has…

Watch this space. Be a week or two but I will report again!

Dave

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