Instructables

Sawsmith Radial Arm Saw -- Enlarge Arbor Hole on a Regular Blade

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Picture of Sawsmith Radial Arm Saw -- Enlarge Arbor Hole on a Regular Blade
A friend has a Sawsmith radial arm saw in good working condition, but getting blades is a problem. A special mount holds the blade on the shaft and uses a 1 1/4 inch hole rather than the standard 5/8 inch hole. The establishment that once sharpened his original blades is no longer in business. I suggested enlarging the 5/8 inch hole in a carbide tipped blade to a 1 1/4 inch hole. The challenge is to be precise and keep the hole centered so the blade does not wobble when finished.

In the photo you see an original blade with 1 1/4 inch hole (satin finish). It is resting on top of a new 9 inch 40 tooth carbide tipped blade with a 5/8 inch arbor hole (chrome finish). You can also see the special mount that requires a 1 1/4 inch arbor hole. The blade fits onto the shoulder on the left piece. The nut on the right screws onto the fitting at the left to lock the blade between the two pieces.

I used a marking pen to outline the size of the new hole on the carbide tipped blade.
 
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Step 1: Mount the blade for enlarging the hole

Picture of Mount the blade for enlarging the hole
I do not have machine tools and decided I could do the job with a faceplate on a wood lathe and a Dremel tool. I have a plywood disc mounted on my faceplate.

I glued a scrap piece of fiberboard at the center of the plywood disc and marked the center while the lathe was running. I scribed a 5/8 inch circle on the scrap of fiberboard.

Step 2: Turn the scrap to make a center for mounting the saw blade

Picture of Turn the scrap to make a center for mounting the saw blade
I turned the scrap of fiberboard to make a round center 5/8 inch in diameter. The hole in the saw blade will fit snugly over this round center and will center the saw blade on the plywood disc with precision. It is important to stop regularly and check so the fit of the blade on the fiberboard is as exact as possible.
RainDog072 years ago
This is a bit off topic, but new 1 1/4 arbor blades are available from Shopsmith www.shopsmith.com and from Forrest www.forestblades.com but I didn't confirm the latter. I just wanted to mention this in case there are folks out there who need a new blade but don't want to modify one.
Phil B (author)  RainDog072 years ago
Your comment is not really off-topic, at all. After I adapted the blade for my friend I found the Shopsmith blades with 1 1/4 inch arbor holes. My friend has always used a 9 inch blade and wanted that size. The Shopsmith blades are 10 inches in size.

I checked the Forrest Blades site, but could not find blades for a 1 1/4 inch arbor.

Thank you for looking and for commenting.
leadpencil3 years ago
Did you try using a hole saw in the tail stock? It seems like it would be a little easier than the dremel.
Phil B (author)  leadpencil3 years ago
The primary concern with the task of enlarging the arbor hole is to maintain a hole that is absolutely on center. My lathe is not capable of mounting a hole saw in the tailstock, but if it were, there is too much possibility some chattering would cause the expanded hole to be a tiny bit off center. I read stories of people who tried to expand the arbor hole in a saw blade with some type of drilling operation, but the final result was not entirely centered. They had to deal with the fact they had ruined a good blade, or manage with a blade that ran with a lot of vibration. Using the Dremel was easy enough and worked very well.
Don Rieg5 years ago
Check with the SawSmith users group on Yahoo. They have a file copy of the drawing needed to reproduce the 5/8 inch acme thread LH and RH nuts which came with the saw originally and allowed the use of 5/8 inch bore blades. I quit using the original 1-1/4 bore blade when the saw was new and never looked back. I believe one of the group members had found a machinist who would make the nuts for $25 a copy.
Phil B (author)  Don Rieg5 years ago
That is another option. Thank you for the information. After I published this Instructable I poked around the Internet and found several posts on various forums by people new to a Sawsmith who were wondering what to do about blades. There will come a time when original owners of the Sawsmiths will pass them to new users. It will be good for those new users to have several options for the blade problem. So far, Google turns up my solution pretty readily and it is easy for a home user to make work.
rimar20005 years ago
You are very smart, Phil. You make me remember an uncle that I had, who was very intelligent and able to fix almost everything that fell into their hands.
Phil B (author)  rimar20005 years ago
Thank you, Rimar. You are very kind. I am thankful to be able to do things like these. They seem simple and easy to me. But, other people have talents for other things I have never been able to do. Those things seem simple and easy to them.
grunthos5 years ago
Great explanation. I love seeing adaptations which enhance or extend the life of tools.
Phil B (author)  grunthos5 years ago
Thanks. I am glad all of the steps were clear for you. Later I always think I should have added or changed this or that. I did another Instructable a few weeks ago on restoring accurate settings to a Sears radial arm saw after the indexing holes have worn into egg-shaped patterns due to wear. It is another one of those that extends the original useful life of a good tool.
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