Thread: Am I on the right track?

Thanks guys. Prior to my last post, I had a look on the net and found out the M3 s1000 code to start it and tried the m5 or m3 to stop it without luck. I haven’t tried m3 s0 or any other combination yet.

I will have a good read through what you have both linked and see what I come up with.

I will say again that I have little to no idea what I’m doing with this side of things, so your help is really appreciated!!!

The hardest part I have found with the computer side of things is that there are so many combinations of what people can and do use as far as programs and controllers and all the different VFD’s available across the globe, there is no one solution for any given issue.

I’m not in any way upset about it, just trying to understand and learn about it.

Cal, remember if you need help i can pop by and give you a hand...need an excuse to take my bike for a ride

Eric, will send you a pm!!

Finally got back to the CNC, I have leveled the spoil board! Took over an hour to complete, I don’t know if this is normal or not 720x720 square.

14 February 2021 - YouTube

14 February 2021 - YouTube

I trammeled the machine prior to leveling.

Hi Cal,

Looking at the video, you could have easily doubled the feedrate at least without any issues, especially as you weren't cutting very deep.

MDF is a particularly abrasive material, you want to cut through it pretty much as fast as you can, otherwise the heat buildup can be very detrimental to the cutters. Good sharp cutters will just power through MDF so you can be fairly aggressive.

One thing you may possibly want to consider down the track when you need to resurface again, is to have your machineable area a little higher, instead of lower, than your spoil table (glue a sheet of MDF on top), this will allow you to use the machine as an open ended router for longer material by just packing up the ends for extra support when machining.

For my machine when I changed the aluminium profile on the table, I glued MDF strips the exact size of my machineable area so I can do longer stuff, and machine sections. It's super handy!

cheers, Ian

Thanks Ian, it’s all a new challenge. What you say makes complete sense though, I will have to work out how to do that!
My next task is to make a mount for a dust shoe, I have the file and the acrylic, just need to learn how to make it.

You can always square the inside corners of the machined area and cut/glue a sheet of mdf to that, and then run your surfacing code again.

That's the beauty of spoilboards, you can just keep gluing new tops over the old one!

With the dust shoe, I don't know what sort of design you have, but the mistake I made with the dust shoe I made early on, was to make the shoe too large a volume area. As I ran it with my extractor via a Dust Deputy (couldn't recommend these enough, they are great!), I didn't want the extractor making a howling noise for many hours on end, so I ran it at around 50%, but the volume in the shoe was too large for the suction, so a lot of stuff didn't get sucked up.

Ideally, make the area surrounded by the brushes as small as possible, but not so small the brushes actually reach the cutter in use. And the shorter the brushes the better.

Although a 100mm port, this one is a really good general design that could be changed to a 50mm/30mm port:

1x CNC Router Dust Shoe for 80mm Diameter Spindle | eBay

cheers, Ian

I looked at your video of machining the spoil board, but my experience is limited to commercial high power machines (8KW spindles and 1KW AC servo motors) so may not be appropriate for your situation.

Our machine was a fully vacuum table system so the spoil board was basically the whole bed size, with the machine working area slightly larger to ensure that bits could overhang the board and not leave unlevelled radii at the extremes of the board. Hence flat surface across the entire bed area, rather than the step that you ended up with. May not be totally practical for you as you need to use fasteners to secure the spoil board. Maybe a 2 layer system with an oversize base board fastened with your preferred hardware and another board covering the machining area fixed with double sided tape on top of that, so that when you face off the board, you don't leave unfaced areas to interfere with mounting work.

With the vac system, we took 0.5 mm of both faces of a new spoil board to remove the skins, the board is then porous and becomes a vacuum diffuser. After that we set bit protrusion into the spoil board to be 0.1mm for cutting out and slightly deeper for through drilling, and set our skimming (relevelling) depth to about .25mm. We skimmed at startup each morning and only during the day if we had enough tracks in the spoilboard to cause vac leaks. For our commercial machine, a skim was a 2 minute job for a 2450 x 1850 table area, using a 80mm diamond tipped bit, shallow depth (0.25mm), and quite high feed rates (about 3x that used for through cutting with 3/8in compression bits). If your hardware can handle it, I think you could increase your feed rate a fair bit with a shallower cut and cut down you skim times a lot.

Thank you both for your words, very helpful indeed! I will set up another board at some stage, I will leave this one on for now to learn on as I won’t be cutting anything big to start with. I have another 1 1/2 sheets to play with as I expected a learning curve. As this was my very first visit into the CNC world I wasn’t sure what feed and rpm to set, the default was 800mm/min and 1000rpm, I had a couple of goes at starting the run and had to work out the direction of cut, cut depth and width and length of cut. I ended up changing it to 1200mm/min and 1500rpm. I’m still trying to finish off a few ukuleles so while glue was drying I turned my attention to the CNC.

The dust shoe I was aiming for is made from acrylic to suit 100mm duct, I have the brush already and it will hook into my 3hp extractor and 150mm ducts, the shoe is not over sized for the application.

I think that the holding hardware will vary due to what I want to cut, some material will be 2mm thick and ukulele shaped, really small pieces of shell for inlays, 18mm ply or mdf and solid timber of various thickness and size along with acrylic. I will have to work out what hold fast suits best for each material.

I really do appreciate everyone’s input, it’s a huge help in this rather large rabbit hole!!

Hi Cal, for small stuff thin double sided 50mm tape works really well, in fact for anything thin it works well. Last time Aldi had them on special I bought a bunch.

For larger stuff the clamp sets from Hare and Forbes are superb, C1024 - C1024 Deluxe Hold Down Clamps | Hare & Forbes Machineryhouse but really more suited to T track.

As a suggestion, I think you'll find clamping will be a real pain for you using a solid sheet. And it's one of the things that will be most time consuming if not done efficiently, along with the occasional damage from stuff shifting of course, which really gets annoying!

I would recommend cutting up a sheet to fit in the section you leveled, and then machine a bunch of holes in a 50mm x 50mm grid on it to fit a bunch of tee nuts from the underside, Timber Inserts Tee Nuts Steel 4 Prongs
– Huck Aerobolt and then countersink screws (not glue) through this board into the base board to firmly attach it. Then you can use clamps anywhere on the grid.

Or the longer term solution would be to rebate strips of 42 x 19 timber on the bottom and screw them to the base to create t-slots you can easily clamp to, then you could use a set like this, C1021 - C1021 5/16" - 18 UNC Thread Hardware Kit | Hare & Forbes Machineryhouse these strips of 42 x 19 would then also act as the spoilboard as well as allowing a means to clamp stuff down.

I bought sets of the clamps and fixing kits when they were on special, and also used the "Mates Rates" to get a further discount, they are sensational!

I'd also highly recommend one of the dust shoes I linked to earlier, it would be very hard to make one as light, and efficient as that, let alone for the money, and the beauty of them is they just unclip to allow cutters changes. Much easier than most options around.

And I probably should add, now you have a CNC, get used to spending money on it! Renovating a house, owning a CNC...not really much difference it seems sometimes! ;-)

cheers, Ian

Thanks Ian, I have a heap of double sided tape in various strengths that I use all the time so that’s good.
I have a busy box with t track and mounts of various sorts that I will get out to see what suits.
From what I have read the work space on this machine has a height of 54mm minus the spoil boar of 12mm which leaves 42mm of work space. I haven’t measured anything yet but by the time a bit is added to the spindle it appears that I am running out of room fast. I am going to raise the spindle and mounts up further on the z axis (I think I set it too low anyway)

Once I have more time to look at everything, I will see how I can add t track or the t nuts to it.

Houses, CNC, instrument building, music, photography, motorcycles all suck finances like black holes!! Lol!!

Hi Cal,

You definitely want to have the spindle mount fairly low down to the cutter end of the spindle, this will make it far more rigid, with the spindle top end mounted it gives the machine a lot of leverage to deflect the spindle when machining.

I can't tell from the pic, does it have one mount or two? If only one I'd highly recommend adding a second to add rigidity. It could even be just a thick piece of plywood drilled/cut to suit.

Rigidity is key, any point pressure is applied or exerted, is a point that can vibrate, flex, etc.

If you start doing guitar bodies you'll especially want it as rigid as possible.

cheers, Ian

There are two mounts, I don’t want to raise it much but it needs to go up a little bit.
At this stage I have no plans to cut out electric guitar bodies, I will stick with making acoustic instruments

Cal,

I ran with a machine surface much like yours for the time I had my old machine, never had to replace the spoil board and as the parts I used were smaller than the workplace never had overhang issues either.
I also machined in a 50mm square grid 0.2mm into the board to align things easier.

As an aside, my clamping technique of choice was masking tape. A piece on the spoil board and another on the workpiece.
I glued the tape together with superglue to let it set. The combo is much cheaper than double sided tape and allows a little bit of movement until the glue sets to fix alignment / square issues if you are doing stuff that requires it.

Never got to the screw inserts and had just started with T-Track experimentation when I had to sell the unit.