Drilling holes in the mill

The (much modified) Zoltair (http://www.rcmodels.net/cnc/hobby/classic.html)
mill project is nearing completion, only one axis to go!!, then the bench,
then the wiring, then more wiring etc.. :-(

http://www.caswa.com/mill.jpg

I used a piece of Silestone synthetic granite for the bed of the machine and
am now giving some thought to how many holes to drill in it....
The idea is to use an\ diamond coring bit I have on order to drill grid of
holes into which I epoxy some flanged inserts. They'll probably be tapped to
M5. The bed is 1m long by 400mm wide and the question is, "What spacing
between the holes?"

My current thinking is that only small parts need small hole spacings, and
small parts don't need as much z height so having larger spacings (75-100mm)
in the bed and bolting a fixture plate with closer spacings (25mm) is OK.

I could just go to smaller spacings (50mm?) but I'm worried about weakening
the Silestone. On the other hand, Z height is my critical resource.
I'd really like to not stuff this up....

Anyone got any experience re this?

PK

-----Original Message-----
From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com]
Sent: Friday, 2 December 2005 3:59 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] File - CCEDBoilerplate.txt


This list is for the discussion of CNC and related topics including CAD,
CAM, EDM, & DRO. The list focuses on the construction of home shop CNC
machines along with the technologies a CNC hobbyist will need in a Home Shop
environment. This list does NOT cover general machining techniques, speeds &
feeds, or any other type question that would have the same answer for a
manual machine. This is not a forum for the discussion of commercial shop
issues, but commercial users are welcome and encouraged to participate in
the discussion of hobby related issues and the building of machines that are
likely to be used in a home shop. This group is strictly aimed at the "home
workshop bunch".

Normally this list is not moderated, but is closely monitored. New member
start out moderated and will be converted to unmoderated once we see a
couple of post. This is done to keep out spammer and other trouble makers.
Any member is subject to moderation or banning without notice if they create
problems on the list or violate any of the below rules. Moderators can be
reached off list at CAD_CAM_EDM_DRO-owner@yahoogroups.com to discuss any
decision or to make suggestion.

We feel that what makes the CCED list so valuable and actively read is that
it is very tightly focused. Members know they can subscribe to this list and
learn useful and valuable information on building a CNC machine without
wasting time on general yak and shop talk. If you are looking for a place to
jaw with some crusty machinists this is not it. If you are looking to learn
about CNC machining and how to implement this in your own workshop then you
have found the right place.

LIST RULES:
o Any request, offers, or discussion of pirated or cracked software is
strictly forbidden and can result in the posters immediate banning without
prior notice.
o Flaming, Off Topic Posts, Arguments, or rabble rousing are not allowed
with the threat of immediate moderation or banning if you feel you must.
o Posting items for sale or auction is allowed as long as the items are
directly related to the subject matter of this list and the privilege is not
abused. Abuse would be considered repeatedly posting the same items in a
short time period or posting a catalog type listing. Posting the prices for
items you have to sell is acceptable and encouraged. All dealing on an item
are to be conducted privately. Listing of items you sell in your signature
is acceptable if it is related to the topics of this list and is not the
primary message in your post.
o Off Topic Posts. This is a large list and we are very serious about
keeping it focused. Off topic posts are very unwelcome. If a moderator
declares a particular discussion as off topic it is to be dropped
immediately. Any discussion or comments regarding the decision are to be
handled off list to the moderators at CAD_CAM_EDM_DRO-owner@yahoogroups.com

Here is our philosophy on determining on and off topic subjects.
We have to make a division somewhere or almost anything can be construed as
being a CNC topic. The general decision is that if the item would have no
meaning if you removed the CNC part it is on topic. On the other hand if the
answer is identical without the CNC in the question it is not an appropriate
topic. As an example if you ask "how do I machine Delran on my CNC machine?"
it is off topic as it is really a general shop question. Machining Delran on
a CNC machine is no different than machining it on a manual machine. If the
question is "Will Delran work as a good split nut on my home designed CNC
router ?" that would be on topic as it is specific to CNC as the wear and
acceptable backlash are different than on a manual machine.

Off topic posts are a big deal with a list the size of the CCED. If every
member asked an off topic question even once a year that is over 8 a day.
Can you imagine the list traffic that would be devoted to non-related issues
if 8 were asked a day when you figure in the replies. If you wish to post on
unlimited subjects go to: rec.crafts.metalworking or
http://www.metalworking.com/news_servers.html
http://groups.yahoo.com/group/jobshophomeshop

We try to apply an even measure in maintaining order on the list. Basically
it works like this: Blatant violation of well know rules get immediate
moderation or banning (reserved for spam, porn, software piracy, unsociable
behavior). Obvious violations that are questionable in intent (they may have
though it was OK) get stern warning. Pushing the envelope, but not clearly
off topic gets not so subtle reminders.

How we interpret the list rules in regard to product promotion on the list:
A onetime announcement regarding a product is acceptable if it is a new item
or product line that would be of interest to the list members and is within
the scope of the items we allow discussion on. This would meant that an
offering similar to the example #1 for drives, motors, machines,
CAD/CAM/Controller software, and other topic related items would be welcome.
A similar post for crack software, cutters, oil, air lines, pills, potions,
porn, vacations, get rich quick, etc. would not be acceptable as they do not
deal with items that are considered acceptable topics for this list.

We do not allow infomercial only posts beyond the onetime announcement
spelled out above and in example #1. This is not to say that the list can
not be used quite successfully for the promotion of a topic related product.
What we do allow is the posting of product promotion in the signature when
replying to or posting on an acceptable topic. So, if you want to
participate in a discussion and share your knowledge of the topic at hand
you are welcome to include a signature reminder or your company and product.
Additionally, you are always welcome to recommend your products when it is a
suitable solution for a posters question. An example would be if someone
asks about suitable widget for their CNC conversion. You would be more than
welcome to suggest your company product and explain why it would be a good
choice if it is an acceptable product for this application. The final
acceptable way to use the list is if you are willing to offer a special
price to list members. This is the only c

Example #1
Topic: New CCED Topic acceptable item announcement.

Dear group,
We are Hyper Co and we are now offering/selling/producing a revolutionary
XYZ widget item. This item will revolutionize hobby CNC with its ability to
jump higher, move faster, be more intuitive, etc than anything offered by
our competitors.

The details on the XYZ widget are as follows:
Blah, blah, blah.

XYZ Widget sells for $$$ and is available directly from Hyper Co of from the
Captive Widget Web Co site at www.CaptiveWidget.com

If you have further questions about the XYZ Widget please feel free to
contact us off list at sales@...

Thanks,
Maggy Marketer
Hyper Co
Anywhere USA


NOTICE: ANY AND ALL MESSAGES POSTED TO THIS GROUP ARE CONSIDERED PUBLIC
DOMAIN, IF YOU DO NOT AGREE; DO NOT POST TO THIS LIST. POSTING TO THIS
LIST WILL BE CONSIDERED AS ACCEPTING THIS CONDITION. NO EXCEPTIONS FOR ANY
MEMBER



Addresses:
FAQ: http://www.ktmarketing.com/faq.html
FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com

Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...,
timg@...
Moderator: pentam@... indigo_red@... davemucha@...
[Moderators]
URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO

OFF Topic POSTS: General Machining
If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
http://www.metalworking.com/news_servers.html

http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.

NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
bill
List Mom
List Owner


Yahoo! Groups Links