miter bar milling TS miter slot?

[drumpriest]

Hi guys, I've been using an 18" steel miter bar with ball bearings on the side for my cross cut sled for a while now, and I've noticed some black stuff in my slot. I am thinking that the bar is milling the slot, does that sound like a reasonable theory?

I made some rock maple replacements tonight, and they are installed for now, but they are a little tight. Fortunately I think the iron will mill the maple, rather than the other way around, so with luck this won't be a problem. I may end up buying some aluminium stock for the bars.

What do you all use for your cross cut sleds?

[bmyers]

UHMW plastic. Like the hard plastic stuff like they use for cutting boards. Slippery yet wont ever mess up my mitre slots.


http://www.woodcraft.com/family.aspx?familyid=4299

Bill

[LarryG]

Red oak, largely because I have a boatload of narrow 4/4 offcuts laying around. Whenever I cut the wanes off a 10'-12' long board and straighten it up, invariably there are some narrow offcut pieces long enough to make sled runners and jig parts and whatever.

[cgallery]

My thread on my UHMW runner method:

http://www.bt3central.com/showthread.php?t=37996

Those runners have been used through a few heating/cooling cycles and have never changed dimensionally. So they ride in the slots just like the day I made them.

[poolhound]

Mine are either walnut or oak primarily for the same reason as Larry. I happen to have a bunch of 3/4 x 3/4 lengths of both. I use them for sled runners and trim and I doubt I will run out for quite a while.

I have found that the walnut works slightly better than the oak.

[JR]

I'm doing a lot jig work just now. I have a pair of those steel bars like you're using, plus some maple and some alder.

I saw one tip you may be able to take advantage of. Find the tight spot on the runner by looking for some discoloration from wear. Use a cabinet scraper on that spot to free it up a bit.

JR

[eezlock]

miter bar milling TS slot?

If you are using the dual miter slot tables for the BT3 saw...that could be the case for sure. I use the Incra miter slot bars on my crosscut sled, it is easy on the dual miter slot table and is easily adjustable when it needs to be.
Sometimes hardwood runners will expand and contract with seasonal humidity and temp. changes, that is why I use the Incra bars, they are very stable and remain true when installed. The uhmw bars are very good also,
but they always have to be ordered, not in stock in local woodworking stores.

[drumpriest]

Ah eezlock, sorry, this is on my PM2000. I'm tempted to just go with the Incra bars, they cost, but not a lot, and I use this sled A LOT! And I live in the northeast, where we get some radical fluctuations in temp. I'm thinking aluminium will not mill the cast top.

Rockler also has UHMV in 3/4 here but they are often not flat, makes me concerned.

thanks all, I appreciate the responses!

[drumpriest]

Well, I just spent some time making new maple runners and tuning them, so that'll do for now. I will eventually build a newer, bigger sled and probably go with the Incra bars when I do that. My current sled is 24"x24", which isn't bad, but obviously could be bigger.