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View trevor7428's profile

Jointer kickback?

by trevor7428
posted 03-23-2016 04:32 PM


28 replies so far

View KYSean's profile

KYSean

119 posts in 4374 days


#1 posted 03-23-2016 04:41 PM

Only by feeding it with no down pressure at all.

-- http://editedwrite.com

View CB_Cohick's profile

CB_Cohick

493 posts in 2028 days


#2 posted 03-23-2016 04:46 PM

I have not had it happen, but feeding against the grain, and as KYSean suggests not keeping enough downward pressure on the workpiece could lead to kickback.

-- Chris - Would work, but I'm too busy reading about woodwork.

View AZWoody's profile

AZWoody

1477 posts in 2001 days


#3 posted 03-23-2016 04:50 PM

Also trying to take too much a bite can increase the risk as well.

View nerdbot's profile

nerdbot

97 posts in 2139 days


#4 posted 03-23-2016 04:50 PM

I had kickback by having too much downward pressure and not feed forward properly. The push pads that came with my (used) jointer had no grip at all, so I had to put significant downward pressure and it was very difficult to push forward. That’s when I experienced a little kickback – though it was more like gouging than kickback. Using proper push pads (on a properly tuned jointer) where I only need minimal downward pressure, I’ve had no problems.

View cdaniels's profile

cdaniels

1320 posts in 2279 days


#5 posted 03-23-2016 04:58 PM

I’ll put myself out there as an ameteur, I was squaring up a 6” block on my jointer one day and didn’t realize that I had the endgrain pointed down. tried running that through and felt like it bout snapped my arm in half. Obvious mistake but I think it counts!

-- Jesus was a carpenter... I'm just saying

View Paul Mayer's profile

Paul Mayer

1124 posts in 3843 days


#6 posted 03-23-2016 05:14 PM

If the work piece is too short this can definitely happen. Anything shorter than 12” becomes risky.

-- Paul Mayer, http://youtube.com/c/toolmetrix

View conifur's profile

conifur

954 posts in 1929 days


#7 posted 03-23-2016 05:22 PM

If the work piece is too short this can definitely happen.
Why would that make a difference all else being equal?

-- Knowledge and experience equals Wisdom, Michael Frankowski

View CharlesA's profile

CharlesA

3431 posts in 2575 days


#8 posted 03-23-2016 05:23 PM



Also trying to take too much a bite can increase the risk as well.

- AZWoody

I thought this too until I started using my jointer for making tapered legs, taking 3/8” off in each pass. It works remarkably well, although I’m always nervous when I do it. I have found that the Grr-Ripp Blocks give me a lot more control.

-- "Man is the only animal which devours his own, for I can apply no milder term to the general prey of the rich on the poor." ~Thomas Jefferson

View Pezking7p's profile

Pezking7p

3327 posts in 2429 days


#9 posted 03-23-2016 05:28 PM



If the work piece is too short this can definitely happen.
Why would that make a difference all else being equal?

- conifur

Because the cutter head area is open and the piece does not get the support it needs. You end up just feeding the piece downwards into the cutter head and it does not like that.

-- -Dan

View nerdbot's profile

nerdbot

97 posts in 2139 days


#10 posted 03-23-2016 06:25 PM



If the work piece is too short this can definitely happen. Anything shorter than 12” becomes risky.

- pmayer

Yeah, I think that was my other problem with my first use. I was just running test pieces and they were pretty short, shy of a foot if I recall correctly.

View trevor7428's profile

trevor7428

266 posts in 1738 days


#11 posted 03-23-2016 07:04 PM


If the work piece is too short this can definitely happen.
Why would that make a difference all else being equal?

- conifur

Because the cutter head area is open and the piece does not get the support it needs. You end up just feeding the piece downwards into the cutter head and it does not like that.

- Pezking7p

Even if you start with pressure on right hand down (just at first) with no downward pressure with left hand (infeed side only) then once the short piece gets to the outfeed table, switch with all the pressure with left hand on outfeed table and only use right to push.

Would this still be feeding the piece downwards into the cutter head?

(I don’t really understand why you can’t run shorter than 12” either) just no you shouldn’t do it, but I want to know can it be done… safely?

-- Thank You Trevor OBrion

View conifur's profile

conifur

954 posts in 1929 days


#12 posted 03-23-2016 07:07 PM

I have run as short as 8”, just have to make sure it stays flat on the tables.

-- Knowledge and experience equals Wisdom, Michael Frankowski

View Paul Mayer's profile

Paul Mayer

1124 posts in 3843 days


#13 posted 03-23-2016 08:10 PM

The actual safe stock length for a given jointer depends on the size of the opening for the cutterhead. It’s really just a matter of having enough length of board supported by the infeed table to keep the board stabilized. As the bed surface that is supporting the work piece becomes shorter, the percentage of board that is over the cutterhead increases compared to that which is supported by the table. The shorter the board, the higher percentage you have “resting” on the cutterhead, and the more tippy the board becomes. That’s when it tips into the cutterhead it kicks back.

An experienced user, if paying close attention, can probably joint 8” stock without incident “most of the time”, but the chances of a kickback are still much higher than with a 12”+ board. I’ve occasionally jointed stock that short, but I would not advise someone who is just learning to attempt it. When I have to joint a shorter piece of stock, I pull out a hand plane. You can joint an 8” board pretty easily, even with a #4 plane.

-- Paul Mayer, http://youtube.com/c/toolmetrix

View teejk02's profile

teejk02

504 posts in 1903 days


#14 posted 03-23-2016 09:00 PM

Short pieces can be done with push-pads…just plan on getting the shallowest cut you can get and repeat (and repeat). Biggest drawback is the tendency to “taper” the board but with shallow passes I’ve never seen a problem with flipping the board head to tail. On my Delta 6” I learned to do that same thing even on longer stock once the really cupped surface is removed. And another thing…keep your tables and fence “slick” (I use Johnson’s paste wax)...”drag” is a safety hazard I think.

View Deaner's profile

Deaner

45 posts in 2864 days


#15 posted 03-23-2016 09:16 PM

3/8’s of an inch Charles…on each pass?? I can’t imagine. Not being critical, just awed:)

Having the sharpest knives possible helps…that and shallow passes. I try to keep my depth around 3/16’s if I have a flat enough board to catch the whole surface, and allow a little extra time for the added passes.

I might try a 3/8” pass tonight, if I can muster the nerve. I’m sure the machine has to be a bit bigger with more HP.

-- Once harm is done, even a fool understands it.

View CharlesA's profile

CharlesA

3431 posts in 2575 days


#16 posted 03-23-2016 09:22 PM


3/8 s of an inch Charles…on each pass?? I can t imagine. Not being critical, just awed:)

Having the sharpest knives possible helps…that and shallow passes. I try to keep my depth around 3/16 s if I have a flat enough board to catch the whole surface, and allow a little extra time for the added passes.

I might try a 3/8” pass tonight, if I can muster the nerve. I m sure the machine has to be a bit bigger with more HP.

- Deaner

Here’s how you do it: Using a Jointer to Taper Legs For Furniture

-- "Man is the only animal which devours his own, for I can apply no milder term to the general prey of the rich on the poor." ~Thomas Jefferson

View teejk02's profile

teejk02

504 posts in 1903 days


#17 posted 03-23-2016 09:24 PM


3/8 s of an inch Charles…on each pass?? I can t imagine. Not being critical, just awed:)

Having the sharpest knives possible helps…that and shallow passes. I try to keep my depth around 3/16 s if I have a flat enough board to catch the whole surface, and allow a little extra time for the added passes.

I might try a 3/8” pass tonight, if I can muster the nerve. I m sure the machine has to be a bit bigger with more HP.

- Deaner

I don’t even attempt 3/16” unless I am cleaning heavy cupped stock. Then I dial it down to < 1/8”. With a 6” jointer and working with at most 6’ stock, what’s a few more passes?

View KYSean's profile

KYSean

119 posts in 4374 days


#18 posted 03-23-2016 10:09 PM

This post reminds me I need new push pads. Mine are getting to slippery to use safely. Thanks.

-- http://editedwrite.com

View teejk02's profile

teejk02

504 posts in 1903 days


#19 posted 03-23-2016 10:23 PM



This post reminds me I need new push pads. Mine are getting to slippery to use safely. Thanks.

- KYSean

Yeah…me too…the foam rubber has a tendency to get a little hard with time (stock Delta’s that came from with a jointer I bought 12 years ago). They still work but not as good.

View conifur's profile

conifur

954 posts in 1929 days


#20 posted 03-23-2016 10:54 PM

Easy enough to make, 3×6” piece of wood or what ever size you want, spray adhesive, some non slip matting and a home made handle/knob, and glue on a tail lip if you want that too. Less then 2$ per pad, wood of course is from the cut off bin, since in my shop and kitchen there is no such thing as scrap.

-- Knowledge and experience equals Wisdom, Michael Frankowski

View CharlesA's profile

CharlesA

3431 posts in 2575 days


#21 posted 03-23-2016 11:12 PM

Just to clarify, I use very small passes unless I am tapering legs. My last two projects on LJ included legs tapered on the jointer. The Shaker style is easy and takes very little clean up when finished. The ones I did on the Mid century modern were a bit tricker, but you can see in the pic the profile of my cutterhead in a 3/8” pass in the photo of the legs.


-- "Man is the only animal which devours his own, for I can apply no milder term to the general prey of the rich on the poor." ~Thomas Jefferson

View splatman's profile

splatman

585 posts in 2176 days


#22 posted 03-24-2016 12:17 AM

Re: push pads becoming slick: Could they be de-slicked with sandpaper? Lay a sheet of sandpaper (maybe 120 grit?) on a flat surface, and slide the pad sideways across the SP. Sideways, so the scratches left by the SP will act like the grooves on shoe soles.

View Pezking7p's profile

Pezking7p

3327 posts in 2429 days


#23 posted 03-24-2016 12:49 AM


If the work piece is too short this can definitely happen.
Why would that make a difference all else being equal?

- conifur

Because the cutter head area is open and the piece does not get the support it needs. You end up just feeding the piece downwards into the cutter head and it does not like that.

- Pezking7p

Even if you start with pressure on right hand down (just at first) with no downward pressure with left hand (infeed side only) then once the short piece gets to the outfeed table, switch with all the pressure with left hand on outfeed table and only use right to push.

Would this still be feeding the piece downwards into the cutter head?

(I don t really understand why you can t run shorter than 12” either) just no you shouldn t do it, but I want to know can it be done… safely?

- trevor7428

You can run shorter than 12”, but the risk becomes greater and you need to have more skill/understanding of how the jointer works. Push pads are a big help.

I jointed 5” boards last night. They were flat, but it probably would not have worked with heavily cupped boards. Need to be careful, as with all power tools.

-- -Dan

View BobAnderton's profile

BobAnderton

311 posts in 3568 days


#24 posted 03-24-2016 03:08 AM

lol, the only time I’ve gotten kickback on the jointer was when I hit a huge lag screw that was hidden in the board. It was not visible on any face of the board. I don’t know how the chainsaw mill missed it. I would have rather dulled a chain than put those big chips in my planer knives. My usual jointer push stick is this big 2 foot long thing made out of a 4×4 with a handle at the back and a rear shoe underneath. I really like it. As a result the kickback was not a safety issue.

-- Bob Anderton - Austin, TX - Nova 3000 lathe, Alaskan Mark III mill, Husqavarna Saw

View trevor7428's profile

trevor7428

266 posts in 1738 days


#25 posted 03-24-2016 04:39 AM



I jointed 5” boards last night.

- Pezking7p

I’m not a professional, but that seems to be pushing it lol. Glad you still have all 10 fingers (or I’m assuming so lol)


My usual jointer push stick is this big 2 foot long thing made out of a 4×4 with a handle at the back and a rear shoe underneath. I really like it. As a result the kickback was not a safety issue.

- BobAnderton

How do you keep downward pressure with a 2 ft push stick, with the handle at the back? Or do you push down with left hand on left side of push stick, only using handle on right side to slide not push down?


The actual safe stock length for a given jointer depends on the size of the opening for the cutterhead. It s really just a matter of having enough length of board supported by the infeed table to keep the board stabilized. As the bed surface that is supporting the work piece becomes shorter, the percentage of board that is over the cutterhead increases compared to that which is supported by the table. The shorter the board, the higher percentage you have “resting” on the cutterhead, and the more tippy the board becomes. That s when it tips into the cutterhead it kicks back.

An experienced user, if paying close attention, can probably joint 8” stock without incident “most of the time”, but the chances of a kickback are still much higher than with a 12”+ board. I ve occasionally jointed stock that short, but I would not advise someone who is just learning to attempt it. When I have to joint a shorter piece of stock, I pull out a hand plane. You can joint an 8” board pretty easily, even with a #4 plane.

- pmayer

Thank you for this explanation! Now everything makes since lol

Thank you

-- Thank You Trevor OBrion

View Roger's profile

Roger

21030 posts in 3581 days


#26 posted 03-25-2016 01:18 AM

Don’t try to take to big of a bite. A little at a time. It takes a little longer, but your equipment will thank you. Also, what everyone else said above. A jointer and our other large tools are very dangerous. Be sure to try and work safely.

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed. [email protected]

View Deaner's profile

Deaner

45 posts in 2864 days


#27 posted 03-31-2016 07:22 PM

I’ll tell’ya Charles, you can’t argue with success- that is a beautiful table, and those are beautifully tapered legs.
Joint on brother, joint on!!

best wishes,
Deaner

-- Once harm is done, even a fool understands it.

View Todd's profile

Todd

421 posts in 2454 days


#28 posted 03-31-2016 10:23 PM

I agree that short pieces cause kickback. It has happened to me once. Scary.

-- Todd, Huntsville, AL

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