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All things Beaver Mill

An open thread for anyone owning or working on. a Beaver Mill

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Peter_H09/07/2018 13:27:01
33 forum posts
19 photos

That helps a lot Bob, thak you. If it worked for you it will do me . It's annoying that there is so little documentation on the many variants. I'm pretty sure my top third bearing was a standard deep groove too. If it is angular contact then I just don't understand how it is supported and takes load.

I would dearly love to make some better drawings for this mill, particularly the head, leadscrews and gearboxes. Does anybody know of a software package that can import a photo/scan, show it faint in the background and let you construct lines, circles, arcs etc over the top of it but as a separately saveable drawing file?. Maybe a DXF. Software eqivelant of tracing. At least you could end up with a drawing with fine, staright lines and maybe remove some ambiguities at the same time. Scaling would be useful, as would snap to a settable imperial or metric grid.

Anybody know of such a program?. Preferably feeware

SillyOldDuffer09/07/2018 15:03:10
Moderator
7686 forum posts
1694 photos
Posted by Peter_H on 09/07/2018 13:27:01:

...

I would dearly love to make some better drawings for this mill, particularly the head, leadscrews and gearboxes. Does anybody know of a software package that can import a photo/scan, show it faint in the background and let you construct lines, circles, arcs etc over the top of it but as a separately saveable drawing file?. Maybe a DXF. Software eqivelant of tracing. At least you could end up with a drawing with fine, staright lines and maybe remove some ambiguities at the same time. Scaling would be useful, as would snap to a settable imperial or metric grid.

Anybody know of such a program?. Preferably feeware

qcad does all that for about £30. (The free version is no longer available but there is an effective free fork called Librecad if you're on a budget.)

Both support layers (ie multiple transparent sheets stacked on top of each other that can be made visible or not) and a layer can be an image (photograph) or a CAD line drawing.

The tracing technique is easy enough: take a photo and import it into Layer 0. Then create Layer 1, and trace lines over the photographic image. Any number of layers can be added if that helps, for example to hold construction lines or text.

What makes tracing tricky is that photographs measure nothing and don't understand scale. They're just a good looking unreliable blob; no dimensional information plus lens distortions. A CAD package is the exact opposite - everything is specified precisely; the drawings are entirely informative.

So you can't do a straight tracing and automatically get good results, rather you have to translate the photo into sensible CAD dimensions using the image as a guide. Accuracy may not matter if you only want a cleaned up line drawing, but it's more work if you need accurate engineering drawings. For what it's worth, my preferred approach to this sort of job is to make a rough pencil drawing labelled with accurately measured dimensions and then use the dimensions to create a CAD drawing. I use qcad for 2D and Fusion360 for 3D.

As LibreCAD is free, give it a try and see how you get on.

Dave

Muzzer09/07/2018 17:45:00
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2904 forum posts
448 photos

Most CAD programs will allow you to import a scanned image and manipulate it (scale, opacity, colour, position etc), then create a 2D sketch on top. You don't need layers as such, as you can simply turn object visibility on and off or even delete the sketch when finished and save as another version.

If you are going to bother drawing it up, you'll probably want to enter the correct dimensions based on actual measurements once you've got the shapes right. Of course, you might then go the extra mile and extrude etc the sketches to create full 3D models.....

Like Dave, I make sketches with accurate dimensions then go straight to CAD. You'll struggle to correct the perspective etc on a photo of a large machine, so I'd give that step a miss.

Murray

Michael Gilligan09/07/2018 18:11:44
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19285 forum posts
960 photos
Posted by SillyOldDuffer on 09/07/2018 15:03:10:

qcad does all that for about £30. (The free version is no longer available ...

.

Dave,

You have me a little confused :

I have just refreshed my "QCAD"

QCAD 3.21.1

These packages contain QCAD, bundled with a free trial of QCAD Professional. The trial runs 15min at a time and can then be restarted. You can order QCAD Professional from our Online Shop and download the full version immediately. Alternatively, you can choose to remove the trial and use the free QCAD Community Edition instead.

**LINK**

https://www.qcad.org/en/download

.

MichaelG.

SillyOldDuffer09/07/2018 18:18:14
Moderator
7686 forum posts
1694 photos
Posted by Michael Gilligan on 09/07/2018 18:11:44:
Posted by SillyOldDuffer on 09/07/2018 15:03:10:

qcad does all that for about £30. (The free version is no longer available ...

.

Dave,

You have me a little confused :

I have just refreshed my "QCAD"

QCAD 3.21.1

These packages contain QCAD, bundled with a free trial of QCAD Professional. The trial runs 15min at a time and can then be restarted. You can order QCAD Professional from our Online Shop and download the full version immediately. Alternatively, you can choose to remove the trial and use the free QCAD Community Edition instead.

 

**LINK**

https://www.qcad.org/en/download

.

MichaelG.

Sorry about that, I gave everyone a bum steer! I thought Ribbonsoft had killed the Community Edition and didn't check the small print properly. Thanks for pointing out the free version is still available

Dave

Edited By SillyOldDuffer on 09/07/2018 18:19:05

Peter_H09/07/2018 18:53:10
33 forum posts
19 photos

Many thanks all, I'll have a look at that software.

> So you can't do a straight tracing and automatically get good results,

> rather you have to translate the photo into sensible CAD dimensions

> So you can't do a straight tracing and automatically get good results,

> rather you have to translate the photo into >sensible CAD dimensions

Yes, I'm aware of that problem. I've looked at photgrammetry a bit over the years, and it can be done from a single unknown camera, but only if you have some markers at known coordinates. Otherwise, you need several photos from different angles and ideally a known calibrated camera.

In this case, the source images I'm referring to are the section diagrams in the Beaver parts manual. There are several good sectional drawings, and from my experience so far, they seem to be mostly to scale. But aside from dimensional info, which would be great, the section drawings could be vastly improved and made much easier to view and interpret. The only releiable source of dimensions we have is to measure parts as they are stripped. But there are other cluse, such as a bearing type being known from the parts list - you immediately know the bore and shaft dimensions, and they can be used as calibration points in a useful small program called "Screnn Calipers" from Iconico. They do more or less what they say, and can store several different calibrations, so you can read directly in mm or inches after calibrating against a known length object in the drawing. Obviously doesn't work well if perspective is involved.

BTW, I saw there is an open source program called FreeCAD - is that related to LibreCad?.

www.iconico.com.

PS - I keep checking "send me email notifications when someone replies.." but I'm not receiving them.

Peter_H10/07/2018 13:03:37
33 forum posts
19 photos

> take a photo and import it into Layer 0. Then create Layer 1, and trace lines over the photographic image

Am doing exactly that now in QCAD, with a sectional view from the VBRP Mk2 manual. Pro version is 33 Euros, per year if you want updates. Ie, 33Eu gets you updates for 1 year, there after it's 33Eu per year for continuous updates.

Excellent program, I am very impressed. It's the way Autocad should have gone 20 years ago instead of the horrible office-like toolbar. The heirachical buttons on QCAD are so easy to use. If only I could find out how to set the grid size for snap to grid!

SillyOldDuffer10/07/2018 14:11:00
Moderator
7686 forum posts
1694 photos

Posted by Peter_H on 09/07/2018 18:53:10:

...

BTW, I saw there is an open source program called FreeCAD - is that related to LibreCad?.

...

It's a different project. FreeCAD is a 3D parametric CAD package, not a 2D drawing tool.

  • In 2D CAD you represent three dimensional objects with drawings of the same object from a number of viewpoints, like top (plan), side, and front. It's the draughtsman's job to make sure the three views make sense. A floor-plan might need only a top view, but more complicated objects need more, possibly also an isometric view to remove ambiguities. There are rules for doing this properly; older British drawings were done in Third-angle Projection, modern drawings are usually First-angle. Again, it's the draughtsman who does this manually. I find 2D very useful for producing templates and simple drawings not requiring professional skills.
  • 3D Parametric CAD takes a different approach. Designs are developed by defining objects, for instance a bolt might be produced by drawing a 2D hexagon, extruding the hexagon to make the head, then drawing a circle on one face of the head and extruding that to make the rod, finally applying a thread to the the rod. If 2D drawings of the object are wanted the package generates them at the end. 3D has many advantages: it's harder to draw impossible objects; objects can carry properties like the material they're made of; objects can be rotated, scaled, & stress analysed; the geometry can be exported as a cutting tool path or as layer definitions for a 3D printer, and much more. Done properly, a 3D model can contain all the information needed to manufacture it, and all the information needed to simulate it.

I use FreeCAD in preference to Fusion360 for simple objects. However, for mechanical design, Fusion360 and other commercial products are more fully featured. May not matter for basic 3D work, but, for example, FreeCAD doesn't support joints and assemblies yet. It will let you draw all the parts of an engine, but not let you assemble them into a complete engine. Fusion360 does let you design parts, and assemble them, and by defining joints, allow parts to move on screen as they would in a working engine.

Dave

Michael Gilligan10/07/2018 14:55:00
avatar
19285 forum posts
960 photos
Posted by Peter_H on 10/07/2018 13:03:37:

If only I could find out how to set the grid size for snap to grid!

.

I run QCAD on a Mac, so details may vary if you are on a different OS

On the top menu, select |QCAD|

From the drop-down, select |Preferences|

In the Application Preferences pane, under 'Defaults for New Drawimgs' select |Grid|

... Follow your nose.

[ noting particularly, the text in Red ]

.

MichaelG.

SillyOldDuffer10/07/2018 17:24:55
Moderator
7686 forum posts
1694 photos
Posted by Michael Gilligan on 10/07/2018 14:55:00:
Posted by Peter_H on 10/07/2018 13:03:37:

If only I could find out how to set the grid size for snap to grid!

.

I run QCAD on a Mac, so details may vary if you are on a different OS

...

Michaels advice is correct for Linux. You can change grid for all Drawings via the Application menu as Michael describes or change it for an Individual drawing from the Drawing menu.

Curious thing about grids - I never change them! Guess I'm lucky that the default suits what I do. The metric system is wonderful...

Dave

Peter_H10/07/2018 18:31:45
33 forum posts
19 photos

I could set the application preferences and change the setting for all new drawings, but I couldn't change it on the drg I had started. In fact, I could start a new drawing, observe the grid snap setting was ok, import the bitmap, and the grid snap just vapourized. Seems it was because of the scale of the drawing being so huge interacting with this setting :

Application Settings->Graphics View -> Grid->Minimum Grid Spacing (pixels)

It appears you can't snap to a grid that is too small to see, which seems a bit odd to me.

SillyOldDuffer10/07/2018 19:21:28
Moderator
7686 forum posts
1694 photos

Hi Peter,

You will soon find on this forum that it doesn't take long before the chap who first asked the question becomes the expert! You're already exploring uncharted territory.

However, I think you shouldn't normally need to change anything in Graphics View. I say this because I believe 'Graphics View' refers to the capability of your computer display screen, not to an image. All it means is that you can't have grid settings smaller than your computer can physically display. I may be wrong.

In Drawing View, which is where you work, grid settings scale automatically with the rest of the drawing as you zoom in and out. That's normally what's wanted.

I tried importing an image and the grid just worked as normal. I suspect your problem is due to altering Graph View settings. It's possible you're doing something advanced and have found a bug in which case the Qcad forum was helpful the only time I needed it.

Dave

Peter_H14/07/2018 13:17:23
33 forum posts
19 photos

No, I haven't touched any setting in graphics view, only the snap grid size under "Grid", which I changed to 0.1mm in all viewports.

I still have the same problem though, this time with a different BMP of similar scale.

Auto grid setting sounds insane. I've worked with CAD for decades and always used the grid as something to snap the cursor to when needed and I've never seen it used any other way by anuyone I've worked with. What would you use an Auto grid for?. I fail to see what use it is if it's size continually changes.

Anyway, the bitmaps I am importing are around 1652 x 2152. They are photocopies of sectional views from the Beaver parts manual with a scale of around 10 pixels per mm. What I am seeing after import is X and Y coord readings in QCad showing 4 decimal places of mm moving linearly with cursor movement, even though grid is set to 0.1mm, and not auto. If I zoom in close enough to see the 0.1mm grid, then the cursor is snapping to 1mm increments (NOT 0.1mm), but the coords change from (1372.1252, 795.2162) to (1373.1252, 796.2162) when moving the cursor up and right by one grid snap. Note, not only is the grid 10x too big, but there is an unwanted four decimal places hanging on the end of each coord. When I imported the BMP, I zoomed right in and put it's origin on the drawings origin.

Peter_H14/07/2018 18:40:56
33 forum posts
19 photos

Well, it seems to work with a 1mm grid now, and the image is almost 10:1, so good enough. I'm reasonably happy with my first attempt, a cross section of the backgear case and cover, traced from the sectional view of the variable speed MK2 head in the parts manual, using QCAD in the manner suggested by Dave (SOD)

beaver mk2 vs head hatched 4bpp.jpg

Michael Gilligan14/07/2018 19:07:10
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19285 forum posts
960 photos

That looks very promising, Peter yes

MichaelG.

SillyOldDuffer14/07/2018 20:01:22
Moderator
7686 forum posts
1694 photos

Posted by Peter_H on 14/07/2018 13:17:23:

...

Auto grid setting sounds insane. I've worked with CAD for decades and always used the grid as something to snap the cursor to when needed and I've never seen it used any other way by anuyone I've worked with. What would you use an Auto grid for?. I fail to see what use it is if it's size continually changes.

...

Method in the madness. The grid scales appropriately as you zoom in and out.

Here I've drawn a 10mm square. The grid has dots at 1mm.

qcadgrid1.jpg

If I zoom in on the top left corner:

qcadgrid2.jpg

the grid scales to a more helpful resolution. The dots are now 0.1mm apart, which is helpful for working on a detail.

Dave

Peter_H14/07/2018 22:31:25
33 forum posts
19 photos

So what is the grid?. Is it a 1mm grid or a 10mm grid?. If I want to snap the cursor to a specific grid multiple, I want it to be defined by me. The whole idea of a grid that changes is an anathema to me. If I want to snap to a 1mm grid, I want exactly that, I don't want it to change to 10mm or 0.1mm depending on zoom level. I cannot see how there is any application for that. The only thing that comes to mind is that maybe you see the grid as some sort of visual aid, where the normal in my experience is that it is something to magnetically snap the cursor to.

The snap settings don't seem to be very stable either. I have twice lost application grid settings between program runs, and whether the grid icon and the auto icons, under the snap menu, are on or off at any particular time seems completely random. However many times I turn Auto off and click Grid on under that menu, they just revert at what feels like random intervals. Either there are some big bugs around this area, or, more likely, I'm missing some setting.

Other than that quirk, it's the best 33EU I ever spent. Excellent piece of software, I'd use it for 2D work by preference.

Bob McDougall14/07/2018 23:09:46
42 forum posts
235 photos

Hi Peter_H, glad your Bever is coming together. Yes the top bearing on the spindle was a common ball race , only the lower two were angled. Although there are different angles you can buy, I guess the larger the angle helps if you cut more drilling than side to side milling ??? I use fusion 360 CAD which has a free version for non commertial use and can also make stl files for 3D printers.

Mark Rand14/07/2018 23:57:53
1081 forum posts
12 photos

I used Nachi 7207-CDUP4 bearings for the bottom pair which are a 15° angular contact, P4 or ABEC7 grade. Top bearing was a deep groove ball bearing.

Edited By Mark Rand on 14/07/2018 23:58:37

Peter_H15/07/2018 09:42:30
33 forum posts
19 photos

Bob - it seems to be more common in spindles to use pairs or triples of the 15 degree angular contacts with a degree of preload. It's a trade off between stiffness, axial and radial load capacity, and maximum speed.There is some good information in the SKF Super Precision Angular Contact Bearing manuals, including some section drawings through various examples of spindle design.

Mark - I've found up the old bearings I exchanged when I partially renovated the Beaver. The lower pair were the original Hoffmann 130ACDEP's and even had the Beaver specification number N1093a engraved on them. I couldn't find any other old angular contact bearings butI did find a 6206, so it looks likely this mill had a deep groove radial bearing as well. I used a pair of Fafnir ABEC-9 2MMV207WI CR DUL

Edited By Peter_H on 15/07/2018 09:44:11

Edited By Peter_H on 15/07/2018 09:44:52

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