Flat surface. Just me?

[Cike]

I've been happy with my BT3000 for years, but I tried something new recently that left me confused and/or disappointed.

I wanted to make some wainscoting, so I purchased a magic molder with a beading profile. It's a tight squeeze to get installed, but it seemed to work just fine in the BT3000 with one exception: the depth of the groove was inconsistent from one end of a board to the other.

After careful examination, I realized that the miter table was not level with the saw top (too high) and the throat plate was also not level (too low). Fortunately, I was able to find info about these issue here on BT3Central, so I removed the plastic shims from the miter table to lower it, and I made some thin cardboard shims for the throat plate to raise it.

It works better now, but the cut depth is still somewhat inconsistent despite lots of playing around with these adjustments and various finger-board configurations.

Has anyone else experienced this kind of thing? Most ripping and cross-cutting wouldn't be effected by this sort of problem, so I guess it's rarely an issue. I'm just trying to figure out if it's a persistent problem with, 1) all BT3x saws, 2) just my BT3x saw, or 3) me.

Would a different saw with a solid cast iron surface eliminate issues like this?

Thanks for any insight!

C

[steve-norrell]

Cike:

Welcome to the forum.

From your post, I assume that your are cutting grooves into boards and not sheet goods. If so, then:

1. Can you do without the miter table? It is designed to be higher than the main table by a very small amount, but since it is parallel to the length of the board, I am not sure it would make much of a difference. If you can't do without it (because of a wide board) then removing the shims is about all you can do.

2. My experience with Ryobi throat plates is that they are somewhat flexible and may bend when you put pressure on them. This would cause different depths, but they would be more randomly spaced along the length. Also, the use of feather boards would help make the downward pressure more consistent.

3. Lastly, you did not mention the use of in-feed and out-feed tables or other support. I have always found it difficult to keep the board level with the table top when it is even only moderately long. The weight of the board will tend to tilt it up and away from the cutters when trying to cut toward the ends. In-feed and out-feed tables would eliminate this problem or at least mitigate it considerably.

Again, welcome to the forum and be assured that others will check in with more (and probably better) suggestions.

Regards, Steve

[LCHIEN]

first thing coming to mind is that you should be using feather boards or pressure rollers to keep the material in contact with the table.
Second the stock ryobi ZCTPs are a bit flexible.

I think the non-flatness affecting the depth in your latest attempt was probably due to the material wavyness more than any non-flatness in the table - its effect would tend to be uniform rather than varying. Cast iron wouldn't help there, but a pressure roller or featherboard would.

[LarryG]

I'm just trying to figure out if it's a persistent problem with, 1) all BT3x saws, 2) just my BT3x saw, or 3) me.

Short answer is, it's all BT3x saws, to varying degrees.

Would a different saw with a solid cast iron surface eliminate issues like this?

Short answer is, Yes, it would.

[JimD]

A flat large top with a flush throat plate would help if not eliminate issues as long as your diagnosis is correct. The wood you are cutting is unlikely to be perfectly flat either, however. My issues are more with wood that is not flat and square than with the BT3100.

Jim

[Wood_workur]

I've never had any problems like this, and I'm using a throat plate that is under the table by 1/16" and I haven't done anything with my SMT. Although it'd be a good idea to have the throat plate flush, with feather boards/a lot of hand pressure over the table, and not the throat plate, I think that would negate the throat plate problems.

[Cike]

Thanks, all, for your insight. I think my problem must have a variety of issues:

- I was using fingerboards (Bench Dog) vertically and horizontally. In order to mount the fingerboards on the fence, I had to cut a piece of laminated board and insert a t-track. But I ended up attaching it to the fence with the brackets from the Ryobi router kit. This probably left too much flexibility in the downward pressure.

- The horizontal fingerboards were attached to the SMT, hence I felt I had to deal with the shim issue. Next time I'll experiment without the SMT and horizontal fingerboards. The boards were about 6 inches wide, but I have some of those Gripprr things that might still allow firm pressure against the fence.

- The boards I was cutting were about 6 feet long. I didn't have in/outfeed tables, but I was using an outfeed stand (one of those Ridgid flip-top stands). It was pretty clumsy, though. I bet a real table, aligned with the saw top, would have helped tremendously, even if it was just a folding banquet table jacked up to the right height.

- The boards simply came from Home Depot, so I assumed that they were square and uniform. I've learned through this process that they really aren't. When I was "finished" cutting all the grooves, etc., I noticed that the tonques on some of the boards were longer than others and ended up sending them all through saw one more time to make sure the overall width was the same.

- When I started to install some of the boards, I noticed that the thickness also varied noticeably from board to board. Unfortunately, I don't have a planer to fix something like this. I hadn't thought of it before, but I wouldn't be surprised if the thickness varied not only from board to board, but also along the length of individual boards. Is there a good way to deal with this kind of thing if you don't have a planer? (I thought planers were only needed for projects using rough cut or recycled wood).

Thanks again for sharing your thoughts!

C

[Russianwolf]

- The boards simply came from Home Depot, so I assumed that they were square and uniform. I've learned through this process that they really aren't. When I was "finished" cutting all the grooves, etc., I noticed that the tonques on some of the boards were longer than others and ended up sending them all through saw one more time to make sure the overall width was the same.

- When I started to install some of the boards, I noticed that the thickness also varied noticeably from board to board. Unfortunately, I don't have a planer to fix something like this. I hadn't thought of it before, but I wouldn't be surprised if the thickness varied not only from board to board, but also along the length of individual boards. Is there a good way to deal with this kind of thing if you don't have a planer? (I thought planers were only needed for projects using rough cut or recycled wood).

Thanks again for sharing your thoughts!

C

Common misconception. a planer is used to accurately thickness boards that 1) are still rough or 2) have been thicknessed by someone else.

You have to remember that they are planing them by bulk. So when the blade on their planer starts to wear a little, the thickness of the board will be effected. And when they decide to change blades, if they aren't getting the new blade in perfect alignment, then this could also affect the thickness.

Then you also have to deal with the fact that wood moves. Even in your own shop, you may thickness two boards to be perfect matches and then set them aside for a month and come back to find that they are now 1/64th different in thickness. That's nature.