Bosch 4000-09 convertion to 4100-09

[Michael Wildt]

Hi,

I have the Bosch 4000-09 and I saw the 4100 saw recently at one of the big box stores. I really like the new design on the riving knife etc. From what I can tell it should be possible to replace those pieces with the new ones.

Any one looked into this before ? Maybe one of you have the new model and could make some measurements for me so I can double check ?

Calling up the local Bosch repair center, while very helpful, they couldn't confirm if the pieces was replaceable between the models. Though he did say it was not recommended etc. I just see it as a nice safety upgrade and way easier to take the kickbacks off for dado cuts.

Thanks,
Michael

[frank shic]

you may have to perform some modifications. my understanding is that you cannot just slap the 4100's riving knife unit into the 4000 that easily.

[Dan Bertenthal]

I "made" a riving knife for my Bosch 4000 by disassembling the guard mechanism and cutting down the splitter into the shape of a riving knife. I used a metal-cutting jigsaw blade to cut the initial shape and then cleaned it up with a file.

This wasn't my idea. Somewhere out there is a thread or webpage that details the process. It works quite well.

This assumes of course that you don't mind sacrificing the blade guard and anti-kickback pawls. If you want to hold on to those, I suppose you could look for some steel of the same thickness and make a riving knife from that.

Regards,
Dan

[frank shic]

gary m. katz writes about this modification on his web site.

[Chris Matus]

Anyone know if the 4100 digital fence gauge will work on the 4000? It goes on sale at Amazon every once in a while. I'm thinking it might work because the fence rails seem the same.

[Michael Wildt]

Just got a reply back from Bosch. They claim the 4100 new riving knife design wont work with the 4000 model. What a bummer since this would have been a nice upgrade.

I still wish there was a local guy around Boston that have one so we could make some measurements. If you're out there let me know. It sure looks like this would be a plug & play solution so I have Bosch suspected playing the legal card.

Thanks for the Gary Katz suggestion, still haven't given up on the other idea though.

Thanks
Michael

[Pete Tevonian]

I saw the new Bosch saw and guard at Lowes recently, and thought the same thing -- getting that blade guard on my 4000 would be excellent. I'm tempted to go back to Lowes and take measurements/photos from their floor model to start doing some thinking about mods/adapter, etc.

Has anyone confirmed how that Smart Guard system comes from Bosch, if you order it as a replacement part? Is the whole assembly one part number -- riving knife, pawls, guard, etc?

--Pete

[Paul Mattaliano]

Has anyone confirmed how that Smart Guard system comes from Bosch, if you order it as a replacement part? Is the whole assembly one part number -- riving knife, pawls, guard, etc?

--Pete

check out www(dot)ereplacementparts(dot)com
click on Bosch logo on left
select "Table Saws"
select model
you can get exploded parts diagrams for all types

let us know if you figure out a way

the taller fence with T tracks on the side is better too. Wonder if that will fit the 4000??

[Chris Padilla]

Big boxes are easy on returns, normally. Buy it, carefully unpack, study/figure it out, and take it back in time to get the refund.

Next, write it all up nicely on a website or here!

[Tom Esh]

Well, it's certainly possible. Here's the parts - all 3 of them:
PartsNewS.jpg

...and here's the result so far:
InstDone.jpg

What works:
The riving knife, modular guard and prawls. WooHoo! I like having the prawls for most cuts, but they're a real hazzard for some operations, like ripping thin strips or tapers. It'll be nice to have the guard but not have to worry about those thin cutoffs getting wedged between the prawl and the blade.
There are two clearance issues:
1) The quick release handle for the riving knife clamp does not clear the plastic half of the blade shroud. I could cut away part of it or remove it, but I think either would greatly comprimise dust collection. (Using the handle is a pretty tight fit anyway unless you have small hands, plus it's in the way for blade changes.) Easiest solution was to replace it with a M6 capscrew (hole was not tapped, but that took all of 30 secs to remedy).
2) Blade cannot be fully lowered with the riving knife in the non thru cut or fully retracted position. Looks like I'll need to cut a slot through a dust vane in the blade shroud casting to make this work and it appears the best way to go at it will be through the throat opening with a stubby jabsaw. My back hurts thinking about it. Hopefully it will be a little easier in the light of day tomorrow with a full load of Advil.
The new throat plate with the finger hole doesn't quite work. Too bad, 'cause that's a really slick feature. The slot is located about 1/8 farther right on the 4100. (The arbor flange might be longer, but since there's no issue aligning the riving knife, maybe they changed the tilt geometry.) In any case there's insufficient tilt clearance without shimming. Considering I use a ZCI most of the time, it's probably not worth the trouble.
If anybody's interested, I can post some more pics and step-by-step info after I hack some aluminum tomorrow.

[Tom Esh]

As promised, here's more detail and pics on the conversion procedure. It's in two parts due to the 5-pic limit per post.
PART I
Other than the Bosch parts, the only additional tooling / hardware I needed for this was a 6mm tap and a 6mm x 16mm (long) cap screw.
Before starting I examined the parts and discovered the guard fork would not lock down on the riving knife. A lever locks it in place with cam tension which is adjustable via two tiny set screws at the back of the fork with a 1.5mm hex key. (These are loose parts after all, so of course nothing is adjusted.) Set screws are stuck fast, but these parts need finesse, not force. Penetrating oil did nothing, so I removed the plastic guard wings (so they wouldn't melt) and set the fork in front of a space heater for a few minutes and they popped right loose. Whew! Didn't break anything yet.
1AdjCam.jpg

I removed the old blade guard / knife assembly and then the old clamping block, keeping the cap screws and set screw hardware since none was included with the new parts.
3RemBlk.jpg

The quick-release clamping lever on the new knife assembly will not clear the blade shroud, so I decided to remove it and replace it with something that would. The new clamp bracket already has a 5mm hole, so it was just a matter of running a 6mm tap through it for a 6x16mm cap screw. (That's the same size as cap screw on the old guard clamp plate, but it's captive so don't try to remove / re-use it.) Also note a 6x20 is too long and will bottom out behind the bracket unless you stack washers under the head.
6Tap.jpg
7CapScr.jpg

Then it's just a matter of dropping the new knife assembly in where the old clamp block came out.
11InsRK2.jpg

[Tom Esh]

PART II
Next, the job I was dreading - cutting a small chunk out of the shroud casting so the knife would clear it when the blade is lowered. Here's the problem (red highlight area where the bottom of the knife contacts a fin in the casting):
12ClProb.jpg

I removed the plasting half of the blade shroud for better access, lowered the knife and marked the cut lines. Going in through the throat opening there's no room to get much muscle or stroke behind the effort, so it took about 20 mins to make two small cuts (including a couple backache breaks). I used a small jab saw with a hacksaw blade, cutting on the pull stroke. A blade with a heavy glove or rag would work just as well. (A glove isn't a bad idea in any case as this operation is a knuckle-banger.)
13Cutng.jpg

A little cleanup and smoothing with a file and it's done...
14CutDn.jpg

Note: Even with this modification the blade cannot be lowered fully with the riving knife in the #3 (full retract) position. The shroud is simply not deep enough. I suspect that means when using a dado set (I don't), you may have to remove the riving knife.

DON'T FORGET TO RE-ALIGN THE RIVING KNIFE per the manual.

One thing I really like about the modular guard system is you can make a zero-clearance insert that does not have to be split all the way to the back if you want to use the guard. I never liked that arrangement because it made the ZCI so flimsy it really had to be screwed down. Now I just pull off the prawls and guard, and slip the ZCI right over the riving knife, then pop the guards back on.
ZCI2.jpg

Parts leftover:
PartsRem.jpg

[Chris Matus]

Hey Tom-

Nice job, and an excellent write up. Thanks!

Did you order the parts directly from Bosch and what was the damage, if you don't mind me asking? I recently broke the blade guard on my 4000, so I'm thinking I might try this since I want to replace it anyway.

[Tom Esh]

Hey Tom-

Nice job, and an excellent write up. Thanks!

Did you order the parts directly from Bosch and what was the damage, if you don't mind me asking? I recently broke the blade guard on my 4000, so I'm thinking I might try this since I want to replace it anyway.

Bosch had one of the parts listed as temporarily unavailable, so I Googled around a bit and found erepacementparts.com. Took about 3 weeks, but it shipped complete. Total damage was around $120. That's not counting the new finger-hole throat plate which despite my careful measuring at the blue borg was not usable. The slot (and apparently blade) position is shifted right about 1/8" on the 4100. There's plenty of adjustment leeway on the guard mount for the other components to work, but the slot edge on the new plate is just too close too the blade to allow tilting it. Sort of like having ZCI on one side only, but considering it's metal, too close for my comfort. The older plate is also substantially heavier and thicker alloy than the new one. I guess if I really want a finger hole in it, I'll just have to figure out a way to bore it myself. If anybody wants a spare 4100 throat plate, PM me - it's your's for the shipping.

[Rick LaPlante]

Cost at ereplacement is up to $145 with shipping now. I jumped in with both feet. Still, much better than buying a whole new saw, and the only step up from this would be almost $600 new. I was VERY relieved to find that someone had already done most of the figuring on this. I was up for it but planned to kill most of a weekend making it work. Really liked the blade guard improvement but that was not enough to sell my 4000 unless it was going to be totally impossible to make adapt. I was just trying to figure how many pieces would have to be swapped out or even cut and welded before it was not worth while.
I would be interested in the throat plate. Have a new jeweler's torch that I've been waiting for a project for and this might be worthy with trying moving the slot.