How to machine a slot in cast Iron

--A suggestion: before you proceed you might want to reinforce the bottom of the table with a couple of steel braces. I'm thinking that where you'd want to cut the miter slot the casting might be a little thin and you could weaken it to a point where it might want to crack in half.

Hey Peter,
How about adding a 1/4" to the table-top, in two pieces, with a 5/8 gap between them. Doesn't even have to be permanent. Your choice of materials and actual coverage required.
Take care.
Brian Lawson, Bothwell, Ontario. XXXXXXXXXXXXXXXXXX

That is a good suggestion "steamer", fortunately there is a web under the area where the slot would go. What sort of reinforcing did you have in mind?
******************************************** ,-._|\ L. Peter Stacey / Oz \ Melbourne Australia \_,--.x/ snipped-for-privacy@melbpc.org.au v
of the table with a couple of steel braces. I'm thinking that where you'd want to cut the miter slot the casting might be a little thin and you could weaken it to a point where it might want to crack in half.

There are router table top kits that include aluminum guide channels and a piece of melanine covered partical board with instuctions for routing the slot. One of these applied over your existing table would be the best solution if you can stand to loose about 0.75 inches of usable cutting depth.
see: leevalley.com under
woordworking>Jig & Fixtures Supplies> Extrusions
"L. Peter Stacey" wrote:

Aside from the 'table thickness issue - your first consideration, this sounds like a job better farmed out. The router might work with *very* careful jigging and a carbide end mill run at minimal speed and a good air blast to clear the dust. Good luck. Ken.

That is easy. Use a couple pieces of 1/4" thick plate material and bolt it to the existing table with the gap in the desired location. This way does not reduce the strength of the existing table.
JRW

On Thu, 29 Jan 2004 09:12:45 +1100, "L. Peter Stacey" vaguely proposed a theory ......and in reply I say!:
That web is there for a reason. The weakness problem still stands. I would be bracing at 90Deg to the slots, at a few places along it (them).
In the end, listen to Brian Lawson.
**************************************************** sorry remove ns from my header address to reply via email
Spike....Spike? Hello?

Now thats why I read RCM. I would not have thought of that.

Yup..routing the table will cause more problems than its worth, even if you can do it.
A couple pieces of aluminum or steel plate is the way to go. Use some filister head counter sunk screws to hold it on.
The nice thing bout adding the plates, is you can make the table much bigger. Seems they are never big enough when you are trying to cut a circle and need a place to put your center.
Gunner
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What you want is some laminate-covered MDF or plywood for an auxilary table and some miter gauge tracks, they're both sold for making router tables. There's some router-only web suppliers out there or you can try Rockler Hardware or Woodcraft. I agree with the other posters, trying to cut a groove in the existing table is a non-starter, particularly given the lack of a planer or large mill. The table casting would have had to have been designed with the slots in mind to start with.
Another method if you don't like wood products for a table cover, get some plate to replace your existing table, add smaller, thinner pieces on top of it to get the slots. Then all you have to do is get some true and square edges on your pieces where they adjoin the slots using the equipment at hand. You'll also need to grind/scrape the top of the table to make it flat.
Stan
Stan

--This is the best suggestion methinks. Easiest to implement, least destructive to the equipment and fast to boot.

Thanks to all the suggestions. Adding a top rather than grooving certainly seems to cause fewer problems and the added advantage of possibly increasing the table size at the same time. Why didn't I think of that ? But that is why I asked the question here. :-) ******************************************** ,-._|\ L. Peter Stacey / Oz \ Melbourne Australia \_,--.x/ snipped-for-privacy@melbpc.org.au v

On Sat, 31 Jan 2004 07:22:40 +1100, "L. Peter Stacey" vaguely proposed a theory ......and in reply I say!:
Ok. So anyone who asks questions here can't think! Huh! meuh! **************************************************** sorry remove ns from my header address to reply via email
Spike....Spike? Hello?