Thread: Homebrew Slotter project !

Hi Guys,

I've now drilled the guides clearance for M6 for the eccentric and counter sunk them for CSK screws. I've also drilled and threaded the holes M6 in the pulley to suit.

17-03-2022-002.jpg 17-03-2022-001.jpg

These two pictures show the guides fitted to the pulley and with the eccentric in place. The red line on the pulley shows the line where the holes can be drilled and threaded for M8 screws. Unfortunately once the pulley is mounted on the lathe faceplate there isn't enough room to turn the corners off the guides or the eccentric plate. The guides foul the lathe bed in the gap. The only alternative is to mount the whole lot on the rotary table and mill the edges off.

As an aside, I've not broken a tap for years !
This morning when tapping one of the M6 holes, I made an involuntary twitch and snapped the tap, right where the shoulder on the tap is. Fortunately there was a large part of the tap above the surface which I was able to grab with pliers and wind it out.

Comming together nicely Baron. You were kissed on the d..k with that broken tap! Lucky!

Simon

Sent from a galaxy far far away

Hi Guys,

I've got some more done on the eccentric for the slotter, so just a few pictures for now !

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These first two pictures are of either side of the eccentric plate. I milled the sides of the slot to match the M8 countersunk hex socket screws. The head of the screw must be flush with the eccentric surface, or slightly below it. At this point all that’s needed is make and to press the bearing shaft into that hole and run a bead of weld around it. As long as I avoid distorting the plate when welding it it should be Ok.

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The Eccentric will be held in position by one or two M8 CSK screws, I've yet to drill and thread the holes in the pulley to do this. The pictures show the two screws that I propose to use. They need shortening but that’s not an issue.

29-03-2022-006.jpg

The length of precision ground bar that I'm going to cut a 25 mm piece from is laid across the pulley. I'm going to drill and thread an M6 hole through the middle to be able to put a retainer on there for the bearing. Last thing I want is the bearing falling off !

That is all for now, I will do an update later. Currently I'm waiting for a piece of square 4mm HSS to arrive, then I can grind a 40 degree cutter to make the multi "V" belt grooves in the pulley.

Originally Posted by BaronJ

At this point all that’s needed is make and to press the bearing shaft into that hole and run a bead of weld around it. As long as I avoid distorting the plate when welding it it should be Ok.

John it is always best to leave meat on to allow for distortion and then do your finish machining after welding, same for work that needs hardening.... grind to size after.

Hi Guys,

A couple of pictures of this mornings endeavours !

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I marked out the line of the five M8 threaded holes that I wanted in order to secure the eccentric to the pulley, separated by approximately 12 mm. Drilled them 7 mm and threaded them M8. The more eagle eyed among you might just spot that the next to the bottom hole has run off by a few thou. This cast iron seems to be extremely hard ! I flattened the point on my Eclipse centre punch when marking out. This caused slight binding on the screw threads, soon rectified with a couple of strokes of a fine file on the inside of the slot.

I need to get some more M6 countersunk screws, those two middle holes look quite bare ! I just have to make the drive pin now and press it into place, and then weld it at the back. A friend suggested that I silver solder it in place. I do have a stick of 30% silver that I could use, though TIG is my preference, particularly after all the practice I got when making the bandsaw stand.

Coming along nicely Baron. Didn't notice the wayward hole until you mentioned it. I had to look twice though!

Simon

Sent from a galaxy far far away

Hi Guys,

I've got the Eccentric bearing pin finished and pressed into the Eccentric plate. I've trimmed it to a length of 24 mm, drilled it 5mm and threaded it M6 all the way through. All I need to do now is to weld it in place so it cannot move. I bought some more M6 CSK screws from Screwfix this morning, so I've now put the missing screws in place.

So the next batch of pictures

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The first picture shows the bearing pin laid on the Eccentric plate and the second with the pin just resting on the hole ready to be pressed in place.

02-04-2022-004.JPG 02-04-2022-003.jpg 02-04-2022-005.JPG

This is the pin now pressed into the Eccentric plate and a picture of the bottom side ready for welding. I scribed a witness line inside the bronze sleeve that was supposed to be a press fit into the pulley bore, and used it to confirm the depth of the pin as it will be when the bearing is in place. It also confirms that I've pressed the pin in straight ! No gaps around the bottom.

One thing that I forgot to mention in my last post is that the five M8 tapped holes in the pulley are on 12 mm centres. The idea is that the Eccentric can be positioned in roughly 6 mm steps.

I haven't done any drawings detailing the Eccentric and the pin yet !

More later.

Hi Guys,

I've done a detailed drawing of the Eccentric drive plate showing the final details. I've not done one for the drive pin since its a very simple item.

Eccentric Plate-1.png

Drive Eccentric-1.png

A final drawing for the Pulley assembly.

Thanks for looking !

Hi Guys,

I've spent some time this morning carefully welding the bearing support pin into the eccentric plate ! Actually much easier than I expected. I used 2 mm diameter steel rod and made two runs around the countersink just to make sure that I got enough penetration. I thought that the weld pool was much further above the surface than it actually was. I'm tempted to just give it a rub on the belt sander to knock any tops off.

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A nice blue colour !

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A close up of the weld. You can see that I just hit the edge of the hole.

looks good. didn't distort the plate at all?

Originally Posted by Zsteve

looks good. didn't distort the plate at all?

Hi Steve, Thanks for your post !

No I didn't get any noticeable distortion ! That was one of the things that bothered me. I kept the initial weld pool down as small as I could and let it cool between the two runs rather than dipping in water to cool it. I find that TIG is very controllable, though I admit that I did have a practice on a bit of scrap to get the arc right.

Actually my need to wear reading glasses doesn't help, the helmet lens distorts the image when it darkens, I actually thought that I was above the metal surface when in fact I was level with it.

Interesting behaviour with your glasses John.
I’ve never noticed anything similar with mine. Biggest thing that screws up my welding vision is the slow buildup of crud on the protective cover lens. It sneaks up slowly without you noticing until you start thinking “why can’t I see clearly”
This was one I changed recently



Good progress BTW !!

Steve

Hi Guys,

I've done a drawing of the Eccentric Yoke that will be moved by the slide and bearing mounted on the pulley.

The yoke is a 150 mm by 200 mm piece of 12 mm steel plate. I intend to use simple strip guides on the sides to control it. Very similar to the guides controlling the adjustable slide plate. I also intend to mount the ram on this plate as well. So its thickness will be an advantage.

Drive Yoke-02.png

The area in blue will be machined out in order for the 6004-2ZZ bearing to fit into. I've yet to add the position of the mounting holes for the ram carrier.

More later.

Hi Guys,

After having a few days of nice weather it was good to get away to the East coast for a while.

Anyway back to the grindstone with a drawing of the Pulley Spindle support bearing housing. Since I now have several 6004ZZ bearings I've done the drawing to accommodate two of them.

I've even got a suitable piece of steel bar that I can use to make it !

Pulley Support Spindle.png

The M6 threaded holes are moved out in order to accommodate the countersunk heads which is why they look to be quite a way from the centre. The dark grey areas on the drawing are where the bearings fit.

More later:

Originally Posted by OxxAndBert

Interesting behaviour with your glasses John.
I’ve never noticed anything similar with mine. Biggest thing that screws up my welding vision is the slow buildup of crud on the protective cover lens. It sneaks up slowly without you noticing until you start thinking “why can’t I see clearly”
This was one I changed recently

Good progress BTW !!

Steve

I don't think I've ever changed one in my Miller, although I'm pretty sure I've got a bunch that came with it stashed somewhere. TIG doesn't usually dirty it much, but MIG gets it looking like your picture pretty quick, at which point I break out the secret weapon...

Meguiars®-PlastX™.png

10 seconds with a drop of that and a rag, and good as new. Quicker than changing the lens! The one I'm using is well over ten years old (if I indeed haven't changed it), and has seen many bottles of gas come and go, as well as a few fair arc rods, and still comes up like new with a polish. I kept expecting it to end up getting covered in scratches, or pockmarked with spatter, at which point I'd of course actually change it over, but it hasn't happened.

Of course, I already had the PlastX sitting around, if you didn't have some already and had no other use for it, you'd need to be chewing through the lenses pretty quick to make it worth investing in that specific product. However, any automotive paint finishing grade polish you might have would probably do almost as well for this job, and if it doesn't - you were going to chuck that lens anyway....