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Zero Clearance Blade Inserts for Old Craftsman Tablesaw

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Forum topic by Lee Imbimbo posted 03-02-2010 10:40 PM 19221 views 3 times favorited 20 replies Add to Favorites Watch
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Lee Imbimbo

69 posts in 2535 days


03-02-2010 10:40 PM

I was wondering if any of your have any experience making a throat insert for a tablesaw, whose factory Balde insert is only 1/8” thick. I have a craftsman model 113.298240, tablesaw that I’ve put a lot of time into restoring, and have gotten everything up and cleaned, and running really smoothly. However, I went to go make a few zero clearance throat plates and found myself staring at a factory throat plate that was only 1/8” thick, and really the saw could only really accommodate about a 1/4” thick plate that was rabbetted to allow for an 1/8” lip.

My thought about how to make this insert was to go ahead and take a 1/4” phenolic (if I can get that), plywood and do the standard procedure to make a throat insert, except for rabbet it to accommodate for the 1/8” lip.

My major concern is that when cranking the blade up to finalize the zero clearance plate that the thin plywood would shear or worse break apart and go flying all across the shop. So I was thinking, what if I just put another layer of 1/2” plywood over top the insert, clamp the whole mess down, and then raise the blade. This should prevent tearout of the blade insert, and at the same time yield the desired results.

My only other concern is using the insert in regular cutting operations. I’d be afraid that the thin clearance blade insert wouldn’t be enough to prevent the blade from ripping it apart in normal operation.

So I thought I’d pick your brains. What I’d really love is if I could find a zero clearance insert similar to that made by Lee Valley, http://www.leevalley.com/wood/page.aspx?c=2&p=55985&cat=1,41080,51225&ap=1 , but obviously this one that they would sell would not work for my model of craftsman.

Thanks for the help.


20 replies so far

View Jeison's profile

Jeison

951 posts in 2570 days


#1 posted 03-02-2010 11:18 PM

Clamping a scrap over to raise the blade through sounds like the way to go. don’t have experience with a thin ZCI so i won’t comment on the safety of it since, well, i’m usually wrong on those things lol. I don’t know if it would work with your model but I’ve seen a few inserts that were held in place with rare earth magnets, once you have the blade slot cut the magnets would hold it in place and should prevent it from being tossed around.

-- - Jei, Rockford IL - When in doubt, spray it with WD-40 and wrap it with duct tape. The details will attend to themselves.

View Builder_Bob's profile

Builder_Bob

161 posts in 2522 days


#2 posted 03-02-2010 11:20 PM

I’m not near my shop at the moment, but I did make a zero clearance insert for my old craftsmen saw. It also required 1/8 thickness plywood which you can get in a hobby shop like this.

If I recall you can add a tab and use the existing screw to hold it in place, but definitely hold it down with something when you make the opening cut. I think I put gallon paint cans on either side of the blade.

It does the job very well, my cuts are absolutely clean with this insert.

-- "The unexpected, when it happens, generally happens when you least expect it."

View SKFrog16's profile

SKFrog16

661 posts in 2663 days


#3 posted 03-02-2010 11:42 PM


This is my Craftsman with a ZCI from www.ttrackusa.com/zeroclearanceinserts
I thought about making my own. but this was faster and better. Besides, they came with adjusting screws to hold them in place from side to side.
When you install a ZCI, you do clamp a piece of plywood over it to hold it in place and raise the blade to create the slot.

-- Methods are many,Principles are few.Methods change often,Principles never do.

View Viking's profile

Viking

878 posts in 2658 days


#4 posted 03-03-2010 12:00 AM

I saw one for Craftsman 10” at Rockler Store yesterday and think it might fit your saw. It is made to replace the thin Craftsman throat plate.

I have an early 1970’s 10 craftsman that I want to put a ZCI in so plan to take my stock plate back in to Houston and compare it against the ZCI at Rockler. Will post results later.

http://www.rockler.com/product.cfm?page=10714&filter=insert

If you shop make one, you may not be able to lower your blade enough to clear the 1/2” material in the center of the ZCI. My blade is just barely below the top surface of the stock throat plate, when fully lowered. The Rockler plate are already partially machined on bottom side for blade clearance after you install ZCI but, before you strt saw and start to raise the blade.

Good Luck!

-- Rick Gustafson - Lost Creek Ranch - Colorado County, Texas

View Randy Sharp's profile

Randy Sharp

363 posts in 3135 days


#5 posted 03-03-2010 12:00 AM

Lee, I made a few new inserts last week. Having used oak before, this time I tried a different material. I had a few pieces of composite deck boards (from Lowe’s) from another project and thought “What the heck, let’s see if it works.

The soft-plastic-like material planed and ripped easily to the approximate size. After locking the new blank in place, the blade raised through without any chance of tearout. I find it to be a very stable and quality insert material.

Give it a whirl. I think you’ll like it!

-- Randy, Tupelo, MS ~ A man who honors his wife will have children who honor their father.

View Sawkerf's profile

Sawkerf

1730 posts in 2531 days


#6 posted 03-03-2010 12:19 AM

When I had a Craftsman, I made my ZCI’s from scraps of 1/4” ply. I cut the shape on the TS and bandsaw, sanding a bit to get a snug fit. Then I drilled a fingerhole and ran them thru the planer to get my thickness. A coat of poly usually sealed them up so I didn’t get any bowing.

When I needed a new one, I lowered the blade (or dado cutter), dropped in a new ZCI, set the fence over it, started the saw and slowly raised the blade.

About once a year, I took about 30 minutes to make up 4-5 blanks, and I could set up a new one in 1-2 minutes.

I do the same process with my Jet TS except that I now use scraps of 1/2” prefinished ply.

-- Adversity doesn't build character...................it reveals it.

View Lee Imbimbo's profile

Lee Imbimbo

69 posts in 2535 days


#7 posted 03-03-2010 06:47 AM

Thank you for the reference to Peachtree, it appears that they advertise a ZCI that fits my model of saw, and it is made of the the kind of material I was hoping for. While their reference guide doesn’t directly list my machines model number they do reference a plate that is 3/32” thick, which sounds like it may be it.

Hopefully, that one will work, otherwise I guess I’ll just have to attempt to make a few myself.

View rweitz's profile

rweitz

115 posts in 2540 days


#8 posted 03-03-2010 09:26 AM

Hi Lee,
I have the same type of insert as you and have been looking at the Peachtree site also. I did make one myself out of acrylic and some scrap wood, but the acrylic cracked and was too thick so I had to router it down – it melts btw. The 1/4” acrylic had too much bow in it for my taste so I glued and screwed some 3/4” scrap to the back after cutting it to fit both inside the opening and slotted for the blade. Once the slot was in place I clamped a 2×4 across the top of the insert to hold it in place as I raised the blade into the ZCI:

Insert out of table

as you can see from the pics it’s not pretty but it does do the job. To keep the thing in place I’m using the existing screw in the front and added a screw in the back that goes through my aluminum table top.

Insert in the table

You can also see the acrylic has cracked where I screwed it down. Polycarbonate might work better but its more spendy and not available at the big box shop. This is really just a trial run. I make everything twice these days just to see if it works before I spend money on real materials! I have been thinking about hitting up a machinist for an aluminum version, or trying to design one with a slot for a piece of wood that is a replaceable insert like one I saw on this site: Sawmill Creek

Insert out of table

I’m pretty sure the Rockler inserts won’t work. They are still too thick and not really the right shape for my saw’s throat opening. (Have to be careful with sentences like that last one or the censors will get me…)

-- You cannot build a reputation on what you are going to do. - Henry Ford

#9 posted 03-03-2010 03:07 PM

I have one of the small Craftsman table saws (8” blade), which I outfitted with a custom machined 5/8” arbor and 3HP motor. I decided to make a zero-clearance insert for mine out of 1/4” Lauan plywood. My goal was to have not only an insert that could be used immediately, but also to have a pattern to use in making future inserts, so I double-stick-taped two pieces of ply together. Then, I used the original steel insert and traced its outline onto the ply, cut the ply oversize on my bandsaw, and used my Oscillating Spindle Sander to get as close to the line as I could. I test fit the insert on the TS several times, each time sanding a little more, until it reached the “perfect” fit—not too tight, not too loose. Then it was rabbeted on the router table to make the edge 1/8” thick, and the two pieces of ply were separated. A 1” hole was drilled in the insert so that it could be removed with my finger.

I used my fence over the top of the insert as I raised the blade into it.

A week or so later, I was horrified to find that the insert had warped and part of it was raised up out of the table saw by about 1/4”. I then applied small pieces of masking tape to the front and back of the plate to give it a little extra length. The insert was then placed into the saw, ends first, meaning it was bent into a slight arch above the saw table. Then, as I pushed the middle of the insert down flat, the ends wedged outward into its cavity, holding the plywood insert firmly in place. It still tries to come out of the saw once in a while, but only by about 1/32”, which I can tolerate.

I may experiment in the future with some different materials to make inserts. Plywood seemed to be the most stable material one could use, other than a metal like brass or aluminum (which can be safely cut with carbide blades), but it must be that in small thicknesses plywood is just as unstable as solid wood. Maybe a phenolic would be better.

-- Lane Custom Guitars and Basses

View rweitz's profile

rweitz

115 posts in 2540 days


#10 posted 03-04-2010 06:11 AM

Hi Lee,
After this post I did more diggin on the I-highway and found this at Woodworking Talk.com

I’ll give this a try and let you know how it works. I’m not really satisfied with the one I have currently – just the excuse I need!

-- You cannot build a reputation on what you are going to do. - Henry Ford

View Lee Imbimbo's profile

Lee Imbimbo

69 posts in 2535 days


#11 posted 03-04-2010 07:21 PM

Just a confirmation, it appears that the guy in your link, rweitz, is hot gluing a strip of wood into the craftsman plate. Is the hot glue really strong enough to prevent that piece from going flying? With the blade spinning forward, that would mean this little strip of wood would be picked up and flung directly at me.

I wonder if there would be a way to get one of my contractor friends to weld some little brackets on let’s say the larger opening Dado Blade Guard, that I could then screw a throat plate to.

Making it similar to the one showcased on Lee Valley that is reusable.

View jacktheripper's profile

jacktheripper

7 posts in 2809 days


#12 posted 03-15-2010 03:59 AM

There is an easy to convert your steel throat plate to a zero clearance one.
The inventor of the Grip-Tite magnetic featherboard at the wood show in Fredricksburg showed me this one.

Sand the bottom of the steel plate and epoxy a thin piece of plywood or masonite to the bottom of the steel plate. Overlap the slot, but stay away from the edges.
Then cut a thin strip of wood and glue in the slot area. Bingo – zero clearance plate- no hassle.

View Lee Imbimbo's profile

Lee Imbimbo

69 posts in 2535 days


#13 posted 03-15-2010 04:38 PM

Thanks for the tip, I think I’ll try something similar. I was thinking about modifying the Dado Blade insert and allowing for enough room to incorporate a wood shim splitter, into it. Hopefully, it will all work out.

View sittingbuller's profile

sittingbuller

16 posts in 2462 days


#14 posted 03-16-2010 02:37 AM

I have used quarter inch plexiglass for a zero clearance insert with good luck

-- Requirements for woodworkers: Sharp mind, sharp wit, sharp tools.

View Sawdust4Blood's profile

Sawdust4Blood

392 posts in 2484 days


#15 posted 03-16-2010 03:07 AM

have you considered using ultra high molecular weight (UHMW) polyethylene? It comes in 1/8 inch sheets (and thicker), machines easily, is slick enough that stock should glide right over it, and should hold up well as either a zero clearance or dado throat plate. It’s also readily available from Woodcraft and others. Great for jigs and fences.

-- Greg, Severn MD

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