# Craftsman Radial Arm Saw will not elevate



## John_S_804 (Oct 11, 2016)

I am unable to elevate (or lower) the arm of my Craftsman 10 inch Radial Arm Saw, Model 315.220100. I bought it used just over ten years ago, and it was a year old at that time. It has been a while since I have had cause to elevate the arm, but I was able to do so in the past. I recall it being a bit hard to turn the hand wheel though.

In searching the internet, I found a four year old thread in this forum about a radial arm saw being difficult to elevate. The answer there was to add lubricant, but in my case the arm still won't move, so I thought I would post my own thread.

When the hand wheel is turned, I can see the two gears under the column turn, but the column does not raise or lower. It appeared the gear was stripped, so I purchased a new one. I'm afraid, however, the new gear is now stripped too. I didn't force it, but the gear still appears to turn, yet the column does not move.

I detached the column from the base assembly and then removed the left and right column supports. The picture below shows the column, with the saw turned upside down.

I have labeled the column, shaft, and nut in the picture. The numbers are from the parts list in the owners manual. You can see a copy at http://www.searspartsdirect.com/model-number/315220100/0247/0744500.html if you click on the tab for the "Column/Elevating Shaft" page.

The shaft is threaded. It passes through the nut. It is my understanding that the hole in the nut is also threaded, and so when the shaft is turned, it pushes up (or pulls down) the nut, which in turn pushes the column up (or pulls it down). If that is correct, it should be easy to turn the shaft by hand, but I am unable to get the shaft to turn.

I can see no rust on the shaft or nut. I also have no reason to believe the threads of the shaft or nut are damaged.

Am I correct in how the shaft and nut work? Should I be able to get it to turn by hand?

Could the grease have hardened into a glue? If so, would a penetrating oil help? When I research penetrating oils, they mention rust, but would they help in this case too?

How can I apply more torque to turn the shaft? I have only tried my hands so far. I'm afraid if I use a wrench or vise grip, I would damage the threads on the shaft.

BTW, if I get this issue resolved, I will have a follow-up question on where and what kind of lubricant to apply. The owners manual does not mention anything about that.

Thanks for taking the time to read through this.
John


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## TomCT2 (May 16, 2014)

if the design is similar to my 1975 model, at the top of the column housing there is a set screw type thing with a jam nut that tightens down on the spline type thingie in the arrow path of #5. if that adjustment is too tight, forcing the crank = broken something.... 

it's a tapered insert - it acts to reduce/eliminate the "slop" when using the 90'/45' presets.


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## Steve Neul (Sep 2, 2011)

Probably to get any real satisfaction you need to completely disassemble the mechanism and clean and lubricate it. You might have to use penetrating oil to get the thing free but afterwards the oil should be cleaned off and only a dry lubricant used. The dust around the use of the saw mixes with any oils to make a paste which hardens and makes it work bad. Also it may be rusted in places you can't see.


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## John_S_804 (Oct 11, 2016)

@TomCT2: There is another set screw at the top of the column on what you call the "spline type thingie". (You can see the bottom set screw in the picture.) I will keep that in mind when I put the saw back together.
@Steve Neul: If and when I get the shaft to turn, I will definitely take the shaft and nut completely apart and clean them thoroughly. I tried some penetrating oil, but no luck after a half hour wait. I will try again after letting it sit overnight.


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## TomCT2 (May 16, 2014)

looked up the number, mine is unlike that model - 
do you have the user manual? pg 28 - gives instructions on how to adjust the column:

"The purpose of this procedure is to check whether the
inner coJumn tube is snug in the housing and to
remove any looseness. Looseness could result in a
poor cut or difficulty in elevating the carriage. "
https://www.manualslib.com/manual/150289/Sears-315-220100.html?page=28#manual

but if the threaded shaft #13 is not turning in the #4 nut - that is an issue for sure...


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## Steve Neul (Sep 2, 2011)

What is going to be hard is getting impatient and crank on the lever too hard and breaking the lever off. This is what I would end up doing.


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## TomCT2 (May 16, 2014)

looking at the exploded view, it appears that model uses a worm gear arrangement.

that shaft does have to turn - a double nut arrangement on the threaded end would be the safest approach - there is no apparent rust / corrosion - and it seems unlikely sawdust could seize the threads....


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## John_S_804 (Oct 11, 2016)

Thanks Tom. The double nut idea did the trick. In the picture you can see that the threads on the shaft that go through the nut do not go all the way to the bottom of the shaft (which is at the top of the picture since the saw is upside down). I don't think a standard nut would fit those threads. But the threads at the very bottom are a standard size. I could fit two 1/2 inch nuts on there. It took a little force, but with the two nuts on it wasn't too difficult to remove the shaft with a wrench.

There appears to be three spots on the shaft where the threads are flawed. Otherwise there is no rust, no sawdust, and no grease turned to glue. One of the bad spots is near the top and really isn't that bad. The worst one is so close to the bottom the nut would never go there. The third one, of course, is where it was stuck in the picture. That's the location where the saw arm is normally positioned. Where the threads are good the nut can be spun quite easily up and down the shaft, but it stops at those three bad spots.

I'll have to decide if I can perhaps file out the bad spots, or if I'll just order a new shaft. I will probably be ordering a new gear anyway. It is hard to see in the picture, but the shaft is not completely round at the bottom. It is flat on one side. The hole in the plastic gear matches that shape. Or at least it did. Now it is pretty much a circle.

As for lubrication. I believe I will need to lubricate the shaft and the outside of the column. In the other thread I linked to in my original question, lithium grease was mentioned a lot. I'm inclined to at least go with a synthetic alternative, but Steve mentioned using a dry lubricant. Could you give me the names of some dry lubricants that would work?

Thanks again Tom. It is a relief to have gotten this unstuck.


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## Steve Neul (Sep 2, 2011)

I've only used this one.


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## TomCT2 (May 16, 2014)

sounds like the shaft has some soft spots that morphed into galled threads. depending on how much you enjoy taking the thing apart, cleaning up the shaft vs replacement. one would hope not to get a double defect . . .

a dry lubricant is best - I use plain ole' powdered graphite. the spray also works I'm sure.

. . . . plastic gear . . . best reason to buy old used equipment (g) - no plastics!


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## Shop_Rat (Dec 22, 2015)

Best stuff ever invented. I use #1 for all my fifth wheel hitch sliding surfaces and the slide out mechanism on the trailer (using a jack screw arrangement). I also spray my mill and drill press columns and spindle with it.

https://www.slipplate.com/

The aerosol can is also the #1 formula (not the black ice).

It forms a coating that resists rust and is slicker than snot on a doorknob.


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## John_S_804 (Oct 11, 2016)

@*Shop_Rat* - Thanks for the recommendation for SLIP Plate. I was almost going to go with something cheaper from Menards because I didn't want to wait for an order from Amazon, but then I found a place that sells it locally. Almost half the price that way too.

I did get a replacement shaft. It's one of the few parts you can still order for this saw.

I just got it all put back together, and it now turns easily. The whole time I was doubting that it would work. It just seemed like the saw would be too heavy for the worm-drive setup to work, but I suppose the fact that you have to turn the wheel several complete revolutions just to move the saw up a few millimeters is why the weight doesn't matter so much.

Next time I take something like this apart though, I really should video record it so I know how to put it back together.

Thanks again for the help and advice.

Now I believe I have a few hours of work ahead to get the saw all aligned.


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