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Chapter 16.5??

Official support for products purchased from the BuildYourTools.com and BuildYourCNC.com sites, and the book "Build Your Own CNC Machine (Technology in Action)" by Patrick Hood-Daniel and James Floyd Kelly.

Chapter 16.5??

Postby philipw » Sat Feb 13, 2010 5:02 pm

Yes, there are some missing details, but I didn't have any problem with parts A and B. Aren't they detailed on pages 176 - 177?

I have detailed a comment about marking the location of the lead screw hole elsewhere in my build notes. Since these parts are cut to a measured length on each build, you can't really use the provided drawing to locate the leadscrew hole. You have to put the whole sliding Y mechanism together and push it to one side and the other for marking it using the holes you already drilled in the gantry sides.

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Chapter 16.5??

Postby philipw » Sat Feb 13, 2010 10:13 pm

Actually, I thought what I said was your comment about there not being drilling instructions for parts A & B was inaccurate as in fact there are detailed instructions for them on pages 176 and 177 in chapter 16.

There are some missing details, on other things, but I had no problem sorting them out as I had read the book and thought through each step.

It might be helpful for you to read my review post after I got the machine moving. It's here in the forum: My review. You'll see that I don't think it's a perfect book either, but I would not have done this without the book, and for that reason, I think the book was terrific.

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Chapter 16.5??

Postby jamesfkelly » Sat Feb 13, 2010 11:26 pm


I'm sorry you're not finding the book useful. We did the best we could... and are happy that others (including Philip) have been able to build the machine based on the plans and our walkthrough.

I can assure you this - there is no Chapter 16.5... there is no missing content. If the wording of Ch17 gives you that impression, than I can't help that... but there was no information cut from the book for pagecount or any other reason. If something is missing, it's just an error on the authors part.

We had to strike a balance... we've had people tell us they wish we had included very specific instructions for drilling holes using Forstner bits. I had one request that we provide a full video showing the entire wiring sequence, start to finish. I had another request asking how to counterbore - not "What is counterboring?" but "How do you counterbore?"

We tried to provide as detailed instructions as we could to build a fully-functional machine. But given the medium (a book), we cannot fulfill every reader's wish for the book.

For Patrick and me, we are proud of the book. We know there are mistakes and errors, but overall the book does what no other book has done to this point - provide as many steps as possible for building a CNC machine.

Again, I'm sorry you're not happy with the book. Please return it if you feel you have wasted your money.


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Chapter 16.5??

Postby roseundy » Tue Feb 16, 2010 10:48 pm

Let me first state that I am happy with the book - I don't want to return it. I think the book is usable as is.

But even if you intentionally left material out because you didn't think it was necessary, that doesn't explain leaving references ("this will be described in Chapter 17") to that material in the book. It comes across as poorly edited.

Just my $.02

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Chapter 16.5??

Postby rebeltaz » Wed Feb 17, 2010 2:30 am


For myself, I can understand the complaints that people have regarding 'missing' information. Notably, things like materials referenced in the book that is supposed to be available on the web site (like the parts layout PDFs - which Patrick has since added BTW), the lack of a standardized bill of materials, inconsistencies in cut dimensions... It kind of reminds me of articles that I have seen in electronics magazines of projects built from scavenged parts . For someone expecting a step-by-step, consistently repeatable project kit without any thinking or common sense required, this book is not for them. But then again, if someone is looking to build a CNC, you would think that that individual would have the required abilities to make use of the book - even if only as a general blueprint.

Having said that, I'd also like to state that I, like so many others, am capable of figuring out most of the 'missing' pieces - although at times it is aggravating to have to try and figure out what the authors were trying to do. Using the book as a guide, with the understanding that it is only that - a guide, I am sure I will have my own CNC up and running soon. I just today received my bearings from Patrick (thank you) and my cross dowels from Lee Valley Veritas. Tommorrow I plan on picking up the MDF and the rest of the hardware. Wish me luck ;)

Let me finish by saying that I am happy with the book, even with it's shortcomings...


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Chapter 16.5??

Postby pconti31 » Wed Feb 17, 2010 2:12 pm

I have noticed in lurking here people have found problems. Philip Wise, who has been the most helpful of anyone, has even stated "Online wins when there is a discrpancy, but there are a couple that don't work either way". However, no one has posted specifics of what those problems were or what path they took in their implementation. (and yes, I read "My Review"). I intend (and propose to others) to simply post specifically what we find in the "Errors - please post any errors found here" section of this forum. I have just finished cutting out the pieces for my machine and will most likely start the drilling and assembly soon. I, of course, have found differences between the book, the cutlist posted on the web site and the pdf plans. In all cases I have so far gone with the pdf plans.

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Chapter 16.5??

Postby Awesomeness » Sat Feb 27, 2010 6:01 am

There have been a number of discussions on this topic. As Paul pointed out, nobody has posted exactly what the issues are. After reading the book, and plans, here is a copy of a list of issues I found with the plans, which I sent to Patrick. I was trying to redraft the machine in AutoCAD Inventor. The page numbers referenced are from the plans. Patrick and I have since had a lot of discussion about this stuff. Keep in mind, this was just my take on it. Enjoy.

- It would be helpful if each piece clearly stated the quantity to make, and if they are all identical or are left-right/mirrored pairings. "Qty: 1", "Qty: 2 (mirrored pair)"?
- If you take some of my suggestions, [which probably spawn from years of actual drafting, and expecting what the drawings should look like if they were being delivered to a professional machinist,] it would be wise to put a legend in the beginning. There is a good example here: http://en.wikipedia.org/wiki/File:Line_types.png which comes from this page http://en.wikipedia.org/wiki/Engineering_drawing
- Just an observation, normally there are standard clearances for hole intended for standard fasteners. For instance, a clearanced hole for a 1/4" machine screw should be 0.266" diameter for "free fit", or 0.257" diameter for "close fit". In MDF it probably doesn't matter, since you can get the screw in even an undersized hole. Or you might have done it intentionally so that it all fits together very tightly, but there won't be much room for error. See http://www.stanford.edu/~jwodin/holes.html
- Pg. 2: "Hole dimeters and dimensions are seldomly repeated for simplicity." The way this is usually carried out, functionally on a drawing, is that the one hole that you dimension you append "typ." to the label, like "1/4 typ.".
- Pg. 2: "Hole dimeters and dimensions are seldomly"
- Pg. 2: "If there is any concern with you having solde responsibility..."
- Pg. 2: "please return the kit and I will refund your purchase in whole within 30 days of purchase" It's ambiguous whether I have 30 days from purchase to return the kit to you, or you have 30 days from purchase to give me my money back.
- Pg. 3: Might consider putting centerlines between the holes, especially the upper-left four. It's appropriate in conventional drafting style, unless you left them out intentionally to simplify the drawing. Inventor complains, that it's not fully dimensioned.
- Pg. 3: I can't remember where you actually talk about this, but the proper term for these type of holes with a larger hole to submerge the head is called "counterbored". "Countersunk" only refers to inclined edges. "Counterbored holes (CBORE) are holes of different depths that share holes concentric centers. There is no angularity in the larger bore.": http://www.tpub.com/content/draftsman/14276/css/14276_160.htm - "A countersink is a conical hole cut into a manufactured object": http://en.wikipedia.org/wiki/Countersink
- Pg. 4: On the main part face, there should be hidden lines to depict the 1/4" holes, where the 1/4"-20 bolts go through the cross-dowels. They provide an indication of the depth to drill them to, and show that all 4 holes need them.
- Pg. 4: I know you reference it in your description, but you might want to put some holes in the part, maybe with hidden lines, or something, to indicate that holes need to be made for your router. Maybe use the holes from the Porter-Cable router you recommended?
- Pg. 4: "The underside of this base should have these holes countersunk" One instance of "countersunk" that may not be correct.
- Pg. 4: Centerlines on the right-side holes.
- Pg. 4: "The four remaining holes is to receive..." Should be "are to".
- Pg. 5: Centerlines between holes.
- Pg. 5: Dimensions of placement for left holes.
- Pg. 6: Basically, this part is really weird. I drew it out, with all the dimensions provided, and it's not symmetrical. The large center hole ends up being not centered between the 4 mounting holes. I'm not sure if that's intended. See the attached image (It's a bit over-dimensioned, for illustrative purposes).
- Pg. 6: Center hole placement - If the part is 3 7/16" wide, and the center of the hole is 1 11/16" from the left, the hole is not centered. Center would be 1 23/32". Is that really how it's supposed to be? To center the hole between the 4 mounting holes, the left dimension should be 1 3/4", but this also has the side effect of still not centering between the 2 connection holes. This may be an issue partially cause by the AutoCAD defaulting to rounding to 16ths of an inch (at least my Inventor did, I had to change it).
- Pg. 6: At first, it looks like there is no dimension showing the vertical placement of the 4 holes on main face. Upon further inspection, there is actually a 5/16" dimension in the top right corner. It might be better to put clearer dimension somewhere, or add a line between the dimension lines.
- Pg. 6: "Countersunk holes will need to receive the #10 nuts."
- Pg. 6: "There are six of these pieces on the machine." Do you counterbore all 6, or just some of them?
- Pg. 7: The placement of the center grouping of 4 holes is off, or mis-dimensioned. The two right-most holes in the drawing are 1" from the right side, and the right-most of the center 4 holes is supposed to be 3.5" from the right side, which would place them centered on the board, and 3.5x as far from the edge. This definately does not look like where they are placed. 2.5" perhaps? Then, the 2 left-most holes of the center 4 are guided only by the dimension that the right-most edge of the 3/4" counterbore is 7/8" from the center of the right-most pair of holes (of the center 4)? That's a pretty crazy dimension. See attached image.
- Pg. 7: There is no vertical spacing dimension for the large hole in the center.
- Pg. 7: "The two holes outside of the larger bearing hole is used to fasten the motor mount..." Should be "are".
- With all these "not centered" problems I'm finding, once the cause is found, check to make sure the problem doesn't extend to other features. The only ones I find are the ones that are obvious because they look like they should be centered, and aren't. Features that are deliberately offset may experience the same innacuracy, but I can't detect it because I don't know how far offset they really should be.
- Pg. 8: "The piece at the bottom serves simpley as extra support"
- Pg. 8: The center hole is not centered. The piece is 6 1/16" wide, but the hole is centered 3" from the left side. It should be 3 1/32". See attached image.
- Pg. 8: Front faces should have hidden lines depicting holes for screws from ends, that go through crossdowels.
- Pg. 9: Front faces should have hidden lines depicting holes for screws from ends, that go through crossdowels.
- Pg. 9: The 1/2" dimension between the small center holes and the outside top edge of the part is hard to see at first.
- Pg. 10: The dimensions between the 5 small holes on the left are missing or difficult to read.
- Pg. 11: There is no dimension for how deep to counterbore the large hole.
- Pg. 12: There is no dimension for the depth of the counterbore, on the top or bottom part.
- Pg. 12: It needs to be clearer that the top and bottom cross dowel holes on each end have their 1/4" screw hole coming from the long sides of the board. I didn't figure this out until I was trying to assemble it.
- Pg. 13: On the top part, there is no vertical spacing for the holes in the middle. Are they in the center of the board?
- Pg. 13: There are no diameters for [what I assume are] crossdowel holes near the edges of the top part.
- Pg. 13: There are no dimensions for how far in from the edge of the board the crossdowel holes are, on the top part. 3/4" maybe?
- Pg. 13: On the bottom part, you couldn't actually place the two smaller holes on the face, or the edge, with the given dimension. It tells you how far apart the two holes are from each other, but not from any known edge. You end up assuming they are centered, and having to calculate how far from the edge to draw/mark them. It's not a very useful pair of dimensions, when if given the distances from the edges no calculation would be needed.
- Pg. 14: There are no dimensions for the spacing of the center holes across the table. There are dimensions for the horizontal spacing, but not the vertical (as it's seen on the paper). They don't seem to line up with the holes in the ends of the table, which are spaced 6" apart, either.
- Pg. 15: What is the difference between the top and bottom of the table? Just that the holes are counterbored? It doesn't seem to show any differences in the drawing.

Then, in the book, you see a lot of other stuff...

- On page 81 of the book, you show the bottom of the table having counterbored holes, and there is a dimension for how far the holes are from the long edge of the table (which was a dimension I pointed out as absent in the downloadable plans, and I had to "make up" when I drew them). This page of the plans is absent form the downloadable plans, and different than the version shown on page 76 of the book for the same bottom half of the table.
- On page 76 of the book, the long dimension of the table is 4' even, and in the downloadable plans, it was longer (4'-1" maybe?)
- On page 138 of the book, this piece is dimensioned (and drawn) TOTALLY different than the one in the downloadable plans.

If you don’t have time to do it right, when will you have time to do it over?
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Chapter 16.5??

Postby philipw » Sat Feb 27, 2010 10:09 pm

That's some work there Guido...

I think the very first thing that needs to be corrected is the issue with the drawing on book page 138, since neither it nor the one in the book is complete or accurate. That was the one that gave me the most trouble.

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Chapter 16.5??

Postby philipw » Mon Mar 01, 2010 11:08 pm

Here is a PDF of the dimensions I used. Keep in mind when you look at my drawing that I made it 5" wide instead of 4" as there is plenty of room and I felt the piece should be wider. I also made my BRAs for this 7" long as again, there is plenty of room. I also used screws through the middle of my BRAs to mount them, so my drawing only shows the middle of the BRA, not the location of the 4 holes as shown in the book. The most critical dimension I found was the one between the centerline of the BRA and the centerline of the motor, which I increased in my build.
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Chapter 16.5??

Postby philipw » Fri Mar 05, 2010 3:37 pm

Good to hear it helped you.

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