Power feed on table saw set up

[macgyver]

I am setting up a table saw for another shop to run a power feeder and I thought I knew what I was doing... It is a used Powermatic 66 and we have a used Powermatic 4 wheel 1hp feeder on it. We are cutting 8/4 solid wood of various species, blanks are rough cut to length 16-24" long. I want to get a glue joint ready edge off the saw.

My issue that I am having is when using the feeder I am getting a belly in the fresh cut edge, what I mean is, if I put two edges together, there is a gap in the middle. If I hand feed it, no gap. Test boards were 4-10" wide with no real difference in result.

I have the feeder set with 2 wheels in front of the blade and 2 behind. It is angled slightly to put pressure on the fence, not much, just a few degrees. I have the wheels fully on the right side of the blade, same side as the fence. This is also the wide side of the throat plate if it matters. The fence is the factory biesemeyer, with no rear clamp. Throat plate is what came with the saw which is a worn out BB ply pc the previous owner made. The wheels on the feeder are not in good shape, will be ordering new ones soon and I am going to make or get a good throat plate.

My initial thought is the throat plate is the main culprit, but I am not fully convinced yet. I don't want to put a clamp on the rear of the fence as I need to move it often for varying widths. I don't know at this time if the fence is moving anyway. Oh, blade is not new but seems to be sharp, I don't know tooth count or brand at this time, it is a lower count 10".

I'll be back at the end of the week and I plan to work on it. I am hoping some of you guys have ran into this and can help me out on it, I didn't think it would be something I had to worry about as my setup at my shop works.

Thanks,
Jason

 

[richard newman]

My first thought is that the fence may be flexing from the pressure. At the beginning and end of the cut you have fewer wheels feeding and less pressure than in the middle. But logically that should give you the opposite problem, a fat cut in the middle.

Is the setup in your shop with a Biesemeyer fence also?

 

[jaguar36]

Yeah, I’d guess the feeder is angled too much into the fence.

 

[macgyver]

Richard, yes it is the same fence, but I'll admit the main thing I run the feeder on is a single width so I will clamp the rear since it never changes. I'll have to try it on my machine today with out a clamp to see.

 

[rons]

My Biesemeyer moves under some moderate force. Had to clamp it in the back with a clamp.
The operation was a router mounted inverted in the left table wing area. The force of the bits
varied, but a raised panel bit is on the high side.

 

[macgyver]

I just ran some tests on my machine with the fence clamped as well as not clamped in the rear. I put an indicator on it to measure side movement as it fed through and either way I am getting a gap in the middle. It is a little less gap with it clamped. With it clamped there was no movement on the indicator but still left a gap. It is a small amount, but not small enough to leave it as is to glue up.
Idk

 

[richard newman]

Have you checked the fence with a straight edge?

 

[macgyver]

I didn't have a straight edge at the other shop, but I laid it on the saw table to see if it was very obviously out of whack. I did not check mine today, didn't think of it. It is weird that it is happening on two different machines though. Makes me think it is something with my setup.

 

[richard newman]

How much of a gap are you actually getting? Those gaps can look huge to the eye, but it's gonna be 2x the error in each cut.

 

[rons]

The Biesemeyer fence board is multi-ply with a white laminate.
If it is not straight, how to replace? Looks like it is a one-way press fit.

 

[macgyver]

I spent some time on it today and double checked the things I had assumed and I found out the fence on mine was not quite straight. The laminated pc on the blade side had been replaced and I took it off and checked the tube which seemed to be as straight as I can expect. Ran some boards that was and they are coming out straight and making a nice joint. I also backed off the pressure of the wheels vertically, I didn't realize I had it cranked down so much.
So, the plan is to put a new side pc on mine and I will have to inspect the fence at the other shop that started all this. I may even take my fence with me just to try it if needed, might take my feeder with newer wheels too..
Thanks for letting me bounce this off someone, I love working by myself, but sometimes it doesn't help when I get too busy to think straight.

Oh, as far as how to replace the side pc, I am going to use phenolic since I have some on hand and just drill and counter sink it and use zip screws. I don't see the advantage of laminating over the screws for mine or the other shops' fence.

 

[rons]

I don't see the advantage of laminating over the screws for mine or the other shops' fence.

No chance for any kind of hang-up.

 

[richard newman]

Glad you're getting a handle on this Jason! Sometimes it's just a combination of factors that magnify each other.

For most woodworking we don't need machines that are as precise as metal working. Unlikely a Biesemeyer fence has been milled or ground perfectly straight, and most users never notice. But when you are going for glue joints, it's a whole other game. I'm thinking a straight line ripsaw, which is used for glue joints, is very accurately machined. I have an old Delta 12/14 table saw, and after I got my Bridgeport and an accurate straight edge, I just had to mill it dead straight.

 

[Bill D]

Method used for shaper fences is to attach the wooden board to the front of the metal fence then run the entire assembly over the jointer to make it flat.
Bill D

 

[macgyver]

I was hoping to find a straight line rip, but all we were coming up with was huge in all aspects, power requirements, foot print and price. Then of course 2 weeks after we get this a small SLR shows up at auction close enough to go pick up that may go cheap.. Going to keep my eye on it.

I do think this will work great for our needs, I just thought I'd get there immediately and not have to work on it much. I just got a message today that their cnc is having a fit, so depending on how bad it is I may not have time to work on the saw like I hoped. At least I have a plan for it now though.

 

[stephen thomas]

Jason -

if you do choose to acquire a previously owned slr; be sure to educate yourself on the chains & tracks if the requirement is indeed glue joint cuts.

only the Diehl system is tune-able for hollow or convex cut.

mattison makes a rugged saw & the design is simpler (most clones are weak copies of that system) but there are weaknesses IMO in the function & wear aspects of the chain & track.

unless someone has stepped in for Mattison, only Diehl products are supported. Chains are in the $10,000+ range each. tracks are anout 1/2 that per each side. My info is a decade old - kind of doubt prices have improved if not gone worse with inflation.

 

[TaperPin]

I think its a mistake to use the factory length fence and a feeder for glue joints like that. I use an 8’ piece of somewhat heavy aluminum 3” C channel clamped to the fence for long glue joints - along with careful hand pressure and freshly waxed fence and top. Many times the shorter fence hides the uneven edge.

All this is assuming the material is dead flat - corkscrewed rough lumber is a poor choice for any kind of glue joint. It also assumes you have a nice smooth waxed out feed table 8’ long.

 

[macgyver]

While I understand your concerns, there are a couple things that pushed going this way. One is the blanks are no longer than 24", so an 8' fence is not needed in my opinion. The second and main concern was the operators. I wish that I could have an operator that could reliably and safely push a board through and get good glue joints, but that wasn't the case. Using the power feeder is safer and more consistent in use with the personnel they have than without. This is true even at lower volume, but once they bumped up the volume, it is just very tiring to do it very long and once a person is tired the chance of doing something wrong increases alot. The power feeder just works for this situation very well. I doubt any major changes will happen any time soon.

As for a follow up, once I got the fence true it has been cutting very consistent edges that are good enough to go right on the glue rack.

 

[TaperPin]

While I understand your concerns, there are a couple things that pushed going this way. One is the blanks are no longer than 24", so an 8' fence is not needed in my opinion. The second and main concern was the operators. I wish that I could have an operator that could reliably and safely push a board through and get good glue joints, but that wasn't the case. Using the power feeder is safer and more consistent in use with the personnel they have than without. This is true even at lower volume, but once they bumped up the volume, it is just very tiring to do it very long and once a person is tired the chance of doing something wrong increases alot. The power feeder just works for this situation very well. I doubt any major changes will happen any time soon.

As for a follow up, once I got the fence true it has been cutting very consistent edges that are good enough to go right on the glue rack.

I thought the pieces were 10’ long - should have read that better.

Id still use something longer than the factory fence - if the board is 24”, the fence should extend 24” in front of the blade for easiest glue Joint.