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Alignment of jointer bed & knives

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Forum topic by Holbs posted 09-22-2015 03:27 AM 697 views 0 times favorited 15 replies Add to Favorites Watch
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Holbs

1371 posts in 1490 days


09-22-2015 03:27 AM

My 6” Rockwell jointer had a fixed outfeed table, so it was easy to use that as a reference for the blade height and infeed table.
This 8” GeeTech is different as both infeed and outfeed table are movable. I am to the point with my refurbishing to start alignment, but I do not know what should be my starting reference point! I had to remove both infeed and outfeed tables for anti-rust, I also removed cutterhead and knives to clean things up and sharpen the knives. Do I set the outfeed table and fence cutterhead hole as a reference to where the outfeed table is suppose to go? Or do i set a magical knife height and reference outfeed & infeed from the top dead center of the knives? argh…

-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"


15 replies so far

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jonah

687 posts in 2760 days


#1 posted 09-22-2015 03:50 AM

You set the outfeed table to something, then shim the infeed table to be co planar with it. Then you set the knives a few thousandths above the outfeed table. Then you set the infeed table for a very light 1/32” cut and never ever touch it again ever. Ever.

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Holbs

1371 posts in 1490 days


#2 posted 09-22-2015 03:53 AM

Setting outfeed table to “something”... can give a hint what that something could be? The fence is attached to the outfeed table. The cutterhead fence cut out I could use as a general reference.
Reading the manual, it says blade height should be 1/16” above cutterhead. But I think that measurement is arbitrary upon how many times the knives have been sharpened.

-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"

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MrUnix

4208 posts in 1660 days


#3 posted 09-22-2015 03:59 AM

I usually will raise the in-feed table to it’s highest position, then drop it down a turn or two and use that as my reference for ‘zero’ cut. Then just set the out-feed table level to it, lock it down and leave it alone.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Holbs

1371 posts in 1490 days


#4 posted 09-22-2015 04:01 AM

Brad… going point. But do you not have to ensure the knives are really secured and set deep into the gibs first before deciding to use the infeed high position as a reference to everything else?

-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"

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MrUnix

4208 posts in 1660 days


#5 posted 09-22-2015 04:06 AM

If they are sitting too proud after that, then you just drop the tables down and realign the knives again; although I’ve never had to yet. But since your manual has a measurement, why don’t you just use it? Put a knife in so that there is 1/16” between the cutter head and the start of the bevel on the knife… then just level the outfeed table to that height (knife at TDC). Doesn’t have to be exact. Once you have your out-feed table in position, just use it like a fixed table from that point on. Don’t forget to reset your depth of cut indicator for the new ‘zero’ position.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Holbs

1371 posts in 1490 days


#6 posted 09-22-2015 04:08 AM

yea… i’ll run with that.

-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"

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jonah

687 posts in 2760 days


#7 posted 09-22-2015 12:09 PM

By “something” I mean “an arbitrary point you choose.” It makes no real difference where you set it (within a certain range of where you can set the knives to) because it’s the surface you reference off of to set up the rest of the tool.

The outfeed table is what you’ll set the knives to, and hence what you’ll set the infeed table to. I have never set my jointer by starting with the infeed table as Brad describes, though there’s no reason that couldn’t work. It’s just an extra step. I found setting the jointer up to be an all day affair the first time I did it, so I am not eager to add extra steps.

You can’t set the outfeed table a lot lower than the minimum height of the knives, so that’s your lower boundary. Your upper boundary is a couple thousandths lower than the highest point you can securely set the knives to. Anywhere in that range is fine.

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pintodeluxe

4853 posts in 2274 days


#8 posted 09-22-2015 03:43 PM

The other spec to consider is how far the cutterhead is spaced from the outfeed table. Most brands have a stated spec for that. For instance on my Delta DJ-20 the spec is .015”.
In other words, the knives will extend .015” from the cutterhead once they are installed.
Start there, and that will help you determine how high to set the outfeed table.

See page 23 for more info. Again, this is the Delta so your specs may vary.
http://www.utpb.edu/docs/default-source/utpb-docs/artsci/art/delta-dj20-jointer-manual.pdf?sfvrsn=4

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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Holbs

1371 posts in 1490 days


#9 posted 09-23-2015 02:27 AM

Logically thinking… I must set the alignment point starting from a fixed position. The only fixed position would be knives and cutterhead since they are not adjustable (well, you could with shims), which would be the back bevel be set 1/16” (or maybe it was 1/32”...I’ll look when it comes time) above the cutterhead, according to the GeeTech manual. Then reference the outfeed table to be a hair lower than the blades (0.002” or so…enough to move a piece of wood 1/8” back towards the infeed table).
  • BUT then I must reference off the outfeed table for each of the 4 knives to ensure the same height all the way across because I can not adjust the width of the outfeed table, only the width of the knives. And THEN, ensure I can co-planer the outfeed and infeed tables.
    This almost seems like which came first: the chicken or the egg.
    (how about that…. three asterisks puts a bullet in a message, didnt know this)

And now what Jonah says, makes sense :)

-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"

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TheFridge

5765 posts in 947 days


#10 posted 09-23-2015 02:35 AM

Put the knives about 1/16 out the cutterhead and go from there

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

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MrUnix

4208 posts in 1660 days


#11 posted 09-23-2015 02:40 AM

Logically thinking… I must set the alignment point starting from a fixed position. The only fixed position would be knives and cutterhead since they are not adjustable [...]

Huh? Cutter head may not be adjustable but the knives sure are! And you should make sure your tables are co-planer before trying to adjust the knives.

Your reference is always the out feed table – that is your ‘fixed’ position, and that is what you set your knives to, and what you set your depth of cut indicator to. Determine where it needs to be, lock it in place, and from that point on, pretend it’s your old jointer with a fixed out feed table – don’t try to over-think it.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Holbs

1371 posts in 1490 days


#12 posted 09-23-2015 02:45 AM

Lots of interesting viewpoints on this :)
Yes, I forgot I can adjust the knives themselves to be AT least 1/16” above the cutterhead… how much safely more, I do not know. I think that is where I get stuck. Was thinking the blades me 1/16” above cutterhead and no more. But I remember I had to adjust the knives to match my outfeed table on my 6”.
So…
1.) I will co-planer the tables FIRST as level to the cutterhead as possible so not to make it too drastic. Maybe that was messing me up or the missing link: co-planer the tables with cutterhead level in mind.
2.) Install knives and start with the bevel 1/16” above cutterhead.
3.) Lower outfeed table to find the HIGHEST point of all 4 knives minus 0.002”.
4.) Outfeed table now becomes reference point for rest of knives.
whalla!

-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"

View MrUnix's profile

MrUnix

4208 posts in 1660 days


#13 posted 09-23-2015 02:55 AM

Install the knives based on measuring the bevel distance from the cutter head? Man, you are a glutton for punishment.

Much easier to just stick in 1 knife temporarily, and get it so the start of the bevel is roughly 1/16” above the head across it’s length. Raise/lower the outfeed table so it’s more or less the same height as that knife at TDC. Lock the out feed table down at that position and don’t touch it again. Put in the rest of the knives and align them all to the locked in position, not moving again, reference point – the out feed table.

Cheers,
Brad

PS: Getting the tables parallel to the head is good if you can, but not absolutely necessary.

-- Brad in FL - To be old and wise, you must first be young and stupid

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Holbs

1371 posts in 1490 days


#14 posted 09-23-2015 02:57 AM

guess I should of said “roughly” 1/16”... set by eye :) of course, I do have a set of those Jointer Buddy’s (magnetic knife holders that you can adjust height with).
Ok..maybe over thinking everything. Time to go watch Fear The Walking Dead to clear my mind :)

-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"

View jonah's profile

jonah

687 posts in 2760 days


#15 posted 09-23-2015 03:22 AM

You are way, way overthinking it. Do what Brad said. Set outfeed, set knives, set infeed.

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