BT3 parts compatibility

[rjwaldren]

I have a Craftsman 21829. Can anyone vouch for parts interchangeability between this post-3100 model and the original BT3000?

I just found a complete BT3 for $30 (w/bad motor) in a distant town that I happen to attending a memorial service in today. It looks to have everything including the accessory kit. I'm sure most of the parts are the same but do the rails have the same profile. I just lost the switch on mine, I hope this will replace it plus alot for the same price as a new switch.

[dbhost]

BT3000 / 21829 differences are a few, but problematic I would think...

Rail profile I believe (but am not certain) is different. The reason I am not certain is that I know, at least from the ones I compared that the 21829 and the BT3100 have the same profile, and the Wide Table kits I have seen listed show compatibility with the BT3000, BT3100, and BT3100-1. Go figure.

Switch, is DEFINATELY different...

Accessory table is different. The 21829 accessory table is pre drilled and has extra reinforcing webbing for mounting a Ryobi router. However you CAN use the BT3x00 accessory table and router mount kit on a 21829 if you wish, or drill the 21829 table for your router and use the rest of the accessory kit.

For $30.00, grab it and part it out. You will make your money back easily...

[LCHIEN]

BT3000 / 21829 differences are a few, but problematic I would think...

Rail profile I believe (but am not certain) is different. The reason I am not certain is that I know, at least from the ones I compared that the 21829 and the BT3100 have the same profile, and the Wide Table kits I have seen listed show compatibility with the BT3000, BT3100, and BT3100-1. Go figure.

Switch, is DEFINATELY different...

Accessory table is different. The 21829 accessory table is pre drilled and has extra reinforcing webbing for mounting a Ryobi router. However you CAN use the BT3x00 accessory table and router mount kit on a 21829 if you wish, or drill the 21829 table for your router and use the rest of the accessory kit.

For $30.00, grab it and part it out. You will make your money back easily...

The profile of the rails there is a slight difference between the 3000 and the 3100/21829 but all the accessories will fit and slide across them, and the T-slots where they mate is identical and will line up perfectly.

its all addressed in the FAQ

[rjwaldren]

I figured the switch would be different, it seems there was a rework of it between versions.

I already have the 21829 accy kit and don't use it for anything other than a wing table, I have a dedicated router table. What I really want is the rails - and the second SMT has the imagination cranking.

Loring, I don't have the FAQ handy right now, but you are saying that they should work for extensions right?

[pelligrini]

Yep they'll work. I have a set of BT3000 half rails always connected on my 21829.

The front extrusion is slightly different and that occurs only at the front edge where the number tape is. All the important parts line up. The BT3000 rails are 2-3/8" wide the black 3100 rails and the 21829 rails are 2-3/4" wide. Those two also hang down further by 1/4". I'll post a photo showing what is going on.

The extrusion thickness of the 21829 rails is about 1/16 of an inch. The thickness of the BT rails are 1/8 and 3/32 in places.

Here's a thread on the differences in the accessory tables: http://www.bt3central.com/showthread.php?t=44263

[pelligrini]

Here's a few shots I took today:
21829 rail on the left, black BT3100 middle, silver BT3000 on the right
The other two photos show the difference in the front extrusions of the 21829 and the silver BT3000.

[rjwaldren]

Excellent. Did you use a kit like the ebay offerings to connect the rails or is that a custom job?

I wasn't able to get by to grab it today, but it doesn't sound like he's getting any other interest in his "broken saw". So I won't be promoting BT3central.com locally til I can get back down there, for purely selfish reasons I confess.

[pelligrini]

I didn't use Komatoast's fasteners. His are a lot stouter then the stock ryobi plates. I used two ryobi connectors on the bottom and a hardwood insert. The insert was fabricated by the previous owner of the half rails. You can see the screw through the rail into the wood insert.

I've got 0 the rail tape set to 10" to the left of tha blade. It will still fold up at 10, but too much further the rails will hit the ground. The half rails have a phenolic plywood router top with a cutout for a jessem route-r-lift FX. The 21829 accessory table and a BT acc. table fit inbetween the plywood and main table. I had to make a leg to hold up the extension. With the router out there it would tip with much downforce. Having a second BT fence is nice if you attach your router fence to it.

There's some photos in this post: http://www.bt3central.com/showpost.p...92&postcount=7

[LCHIEN]

Here's a few shots I took today:
21829 rail on the left, black BT3100 middle, silver BT3000 on the right
The other two photos show the difference in the front extrusions of the 21829 and the silver BT3000.

Pictures and description most enlightening.

First time I've seen all three together to compare exactly.

[pelligrini]

Photos really do tell a good story. The only other difference, and it's really not worth noting most of the time, is that the 2 outside corners of the top small slot on the front rail are slightly rounded over on the 21829 and BT3100 rails. The BT3000 rails have a profile that is more square.

Those two little corners sticking up when connecting the BT3000 rails to the others will occaisionally hang up a fence. A couple pases with a file will help quite a bit.

The differences in the extended front when connecting the different profiles do not affect the fence movement. At least that is the case with the casting on the 21829 and BT3100 fences. I don't know if the BT3000 casting is different. I doubt it though.

[docrowan]

Well, dang. I just presumed the silver BT3000 rails would not connect to the black BT3100 rails. Not sure if I like the looks of it, but it's a table saw not a work of art or even a car. I have a 7 inch section of silver rails I need to look at installing on my BT3100 when I get back from vacation.

Thanks for the posts, Pelligrini.

[pelligrini]

Chris- You ought to look into doing an insert connector. The plates can be a pain for permanently connected extensions. They are always in the way with my front acc table clamp. They'll probably be easier to fabricate when using all BT rails. I need to redo mine or shim the 21829 ends because of the differences in extrusion thicknesses.

[docrowan]

Yep, already started noodling with that in my head. It was interesting to see the difference in thickness of the rail extrusion between the BT's and the 21829's. Looks like they 6Sigma'd it and found a way to reduce some cost. Not necessarily a bad thing, but I imagine it's caused us "frankensteins" a little grief as we're cobbling together customized BT3x's.

[pelligrini]

Not too many people comment about the extrusion thicknesses, but it's a PIA when you're mating the two with an insert. Aluminum prices were pretty high when the 21829 was introduced. Most of the parts in that model used less of that element. No router plate, thinner extrusions, no ribs on tables, thinner rails, etc.

Pretty much, all the parts match up where it counts. I don't think anyone has looked at the motors and the underneath castings yet.

[JR]

Very interesting, Pellegrini! That's a significant addition to basic BT lore.

I say he gets the thong!

JR