RFQ - custom 43mm spindle mount

[HankMcSpank]

Guys, I've just ordered a small CNC machine from Asia (http://www.ebay.co.uk/itm/Panther-210-CNC-Router-Engraver-mill-milling-Machine-/230676949843?pt=LH_DefaultDomain_3&hash=item35b56aeb53) & now need a spindle mount to affix my Proxxon BFW40/e to it ( http://ebay.bzt-cnc.de/sc/zubehoer/proxxon/bild1.jpg ...this Proxxon spindle has a 43mm collar.

Here's the overall vibe of what I'm thinking...

http://img684.imageshack.us/img684/3115/lowerspindlemount.jpg (http://imageshack.us/photo/my-images/684/lowerspindlemount.jpg/)


(I've omitted the clamping aspect...as I'm figuring who ever is confident enough to quote me will also be confident enough to put their own clamping arrangment in place! The key thing is those m5 holes - they've got to be bang on (71mm between centres - here's the manafacturer's Z plane mounting plate drawing - http://www.motor-star.com/Z%20AXIS%20SCREW%20HOLE%20-%201.jpg ).

Re spindle mount thickness...hmm, difficult, my spindle is quite chunky at 2kg (far too big for such a little machine really), so I don't want a *huge* amount of weight attributed to the mounts alone (although I'm conscious of the heatsinking 'win' a larger mount brings) ...but it'll probably need to be something 25mm thick?

Anyway, my 'first stab' DXF file is attached which has all the dimensions.

PM me if interested....don't spend overly long ...a ballpark figure via PM would be nice to kick this off! (also don't be offended if I baulk - I was made redundant in June - living off my savings - no benefits for Hank! - & I'm presently try to dig myself out of this mess by getting some piddly little products to market! I can actually mill my own mount out of mdf or acrylic, but would rather have Ali)

[Web Goblin]

My machine is down for a little repair/mod or I would quote you for one, got some 25mm alu in the shop. I'm sure Jonathan will be along soon to have a look at it. My plan as well was to do some motor mounts for ebay perhaps but we will see how that goes.
I have had a play with your dxf and I think you may have a problem with getting 5mm bolts into the holes. I take it you would be using a 25 to 30mm long bolt depending on the thickness of the tool post you are bolting on to. You might need to reduce your outer diameter a bit to be able to get the bolts in without them hitting the side of the mount. But then again you could always mount studs in the tool post then just fit nuts to clamp the mount to the post. Might also be better to make the holes 1mm larger diameter, this will give you a bit of adjustment. The 71mm pitch isnt a problem, you can just mill a drilling jig to get it spot on if you really want to.

Ian

[Web Goblin]

4760How would this do you?

Ian

[HankMcSpank]

Hi Ian,

Good spot with the mounting bolts., I'm liking what you've done...

http://img846.imageshack.us/img846/9184/spindlemount.jpg (http://imageshack.us/photo/my-images/846/spindlemount.jpg/)


In this fine forums' opinion, would 25mm be about right for such a mount? (just checked the spec 4.2kg of my spindle ....yikes, no wonder my CNC Z plane stepper was struggling on my homemade machine!). Also, I need that amount of 'throw' from the back of the mount to the spindle centre (because the upper portion of Proxxon spindle measures about 82mm diameter) ...just wondering about the mount's weight here ....would it be worth removing some material out of that long back edge (a recess?!) to remove some weight from the mount?

Oh btw...


. The 71mm pitch isnt a problem, you can just mill a drilling jig to get it spot on if you really want to.

That's why I like this place so much ...to my non engineering background, this is pure enlightenment! (ie you've solved a problem not just for this, but for all those other "hmm, how do I drill two holes of required spacing accurately" ...the answer simple .... make a drilling jig/template on my CNC - doh...[shakes head & mutters under his breath] Hank, you're really not the fastest guy when it comes to stuff like this!)

[John S]

19mm or 3/4" would be fine, there,s nothing there in the extra 6mm or 1/4" that will add anything to the design.

[Jonathan]

Jonathan will be along soon to have a look at it.

I'm 12 hours late :(


My plan as well was to do some motor mounts for ebay perhaps but we will see how that goes.

You're not the first.


I have had a play with your dxf and I think you may have a problem with getting 5mm bolts into the holes.

The other way to get round that is make the hole a slot, then you can insert the bolt at an angle to get round it. To ensure that the screw fails before the thread strips you need about 8mm thread engagement with M5 into aluminium, so since the mount is 18mm thick you'll be fine with a 25mm bolt. Not that it really makes a lot of difference here...


The 71mm pitch isnt a problem, you can just mill a drilling jig to get it spot on if you really want to.

I'd just spot and drill it on the milling machine (or router would work, but not as fast)...no need for a jig as it's a one off.

Anyway..
I have some 3/4" aluminium, so I could cut you one from that. Also got some 1.5", but that's a bit much...especially as that bolt has to squash it to clamp which is going to take more force with a greater thickness. Could have more bolts if it was thicker though. Two clamping bolts could fit with 3/4" but I doubt it's necessary.
The problem with me doing it is I'm at University so I can only come home to do it some weekends. Got some bits to cut out for luke11cnc next weekend and a spindle mount... so if you don't mind waiting a couple of weeks I can do it.

[John S]

Looking for a drawing I did a while ago and came up with this picture.

4761

Not suitable for your use because you can't get the centres in you need but it was an exercise on keyhole milling to get water passages nearly all the way round the mount to keep the Kress bearings cool.

Not sure if any are left but i don't use my Kress now I have the high speed spindle so I'll do a search and see what I have

[HankMcSpank]

Loving the name - waterkress! lol LOL. (I don't get out much)

Thanks for the input guys...sheesh I don't know, here was I thinking you were all stood to attention, polishing your machines while waiting for the next job to come in; -)

The situation is, my machine won't even be despatched for two more days....it's coming from Korea (I like to buy from countries associated with top engineering quality hehe!) ...so I'll likely not have it for 7-10 days, but man, it's going to be painful to have it here & not be able to use it......remember - I've been 2.5 years using my homemade CNC constructed from junk (and the end result wasn't far from the input material!) - I'm gonna be like a sailor who's been at sea for three months, pulling into the harbour at Rio de Janeiro & who's just swallowed a tablet of Viagra.

[Jonathan]

Sure that's enough rotary tables!

I notice you've done the other clamping method. I wonder which way is strongest.


it was an exercise on keyhole milling to get water passages nearly all the way round the mount to keep the Kress bearings cool.

I was thinking of doing something like that with the DIY brushless spindle as the bearing temperature on those seems to be an issue...if I can find cheap 8mm bore angular contact bearings.

1000th post...

[John S]

Don't know about strongest, with the clamp method once the slit is compressed that's it.
With the cotter method there is no limit how far you could pull it thru or better to say how much damage a ham fisted ijit could do.

1001 post, need another bicky.

[HankMcSpank]

Jonathan...apparently your PM box is full!

[Lee Roberts]

Hank, please see below:

This mount has been designed for use with the Kress range of spindles and will fit the 1050, 800 and the 530 models. It will also be suitable for any spindle that has a 43mm spigot, so an example would be the DeWalt Die Grinders.


4763

- 30mm Aluminium
- Centre Line: 57mm
- Fixing Centre:90mm
- Fixing Flange: 113mm W x 30mm H x 15mm T
- Price £38

I don’t know how much these guys are looking at for a custom mount, with one of these you could then get a simple rectangle plate machined to give you the centre's you need, bolting this mount to that plate. It MAY work out cheaper doing it this way.

Let me know if you’re interested, I only have one left at the moment.

.Me

[Jonathan]

Jonathan...apparently your PM box is full!

Oh not again...
I'll delete some messages now.

Feel free to email me if it happens again.

Edit: Done

[black5f]

This is how I do mine, easy and very stiff:

4764

Drawing to your dimensions. You could mill the front edge to make thinner, reduce bolt length etc. I would use studs made to length, not bolts.
Tom

[HankMcSpank]

Thanks guys...(& thanks Tom for taking the time to draw up what you did), the associated contracts have now been drawn up, signed/witnessed :lol: so I guess we can draw a line under this RFQ.

[HankMcSpank]

And here's the end result...

http://img267.imageshack.us/img267/6049/mountr.jpg (http://imageshack.us/photo/my-images/267/mountr.jpg/)
(I took out Jonathan's original supplied socket head pinch bolt, as I needed to something to attach my auto zero croc clip too - therefore a longer bolt was pressed into service)

A hearty thanks to Jonathan for an excellent service ....and clever design (wavy edges for more surface area), well made & delivered in a timely manner.

In the end I had to design/make a backplate & 'upper mount' out of acrylic (it really needs to be ali plate, but I have no ali plate, and besides & it's likely beyond the cutting ability of my modest setup - what's the easiest type of ali to machine?).

My very small CNC machine ony arrived yesterday....can you believe the first friggin part I made today, I cut into the bed!!! (there'll be plenty more where that came from - they reckon the leadscrew pitch is 1.2mm - I reckon it aint, but I should have checked first!!).

You can see how my spindle dwarfs the whole machine though it looks worse in the photo than it actually is (you can now realise why I'm keen to get a different, smaller lighter spindle!) ....but even though it weighs 4kg, the supplied toy town-esque NEM 17 motors seem ok with it!

Anyway, thanks once again to Jonathan!