Acceptable Runout Tolerances for a Shaper Spindle

      High-quality machinery has minimal runout. Excessive runout is a safety risk and a source of trouble. December 20, 2005

My shaper is not performing well. Based on the dial indicator, with the 1.25" spindle at full height, I measure .008" runout. How do I fix this? I have heard the phrase "shim the spindle" but don't know how. What is acceptable runout for a large heavy-duty shaper (7.5 hp and 850 lbs)

Also, what are acceptable tolerances, runout, and setup criteria for the other basics, such as table saw, jointer, and planer?

Is it reasonable to dial in my foreign-made Grizzly machinery to tight tolerance? The table saw isn't much better at .04". They all vibrate excessively and I notice this when I use US made Powermatics, Deltas and SCM / SCMI's at another shop, then resume using my own machinery. Should I just accept that I got what I paid for, or do I need to invest a day or two to setups?

Forum Responses
(Architectural Woodworking Forum)
From contributor A:
I think the part about shimming the spindle cartridge is to make the shaft true to the table 360 degrees. You may have seen a diagram from your shaper knife maker showing a straight edge clamped between two nuts on the shaft and that can be spun to take measurements in a full circle and the cartridge is shimmed to where the measurement from the bottom of the straight edge to the table top is even in 360 degree path.

From the original questioner:
The spindle itself is .08" variation.

From contributor B:
Please say it is .008 not .08!! I wouldn't even turn it on if it is .08. Either way, .008 is quite excessive. I would pull the spindle out and check the bearings, and replace them with a quality product. With the bearings off, place the spindle in V-blocks and check the runout from the journal to the spindle. They should be .0005 TIR or better, but you could live with .001. Check it in several places. If it is excessive near the shoulder, it was machined wrong. If it is good near the shoulder and excessive near the end, it is bent and should be scrapped. At this point I would nuke the whole machine, but that's my opinion.

From contributor C:
Like contributor B said, even 0.008 is way too far out. I would take the spindle out and bring it to a grinding shop that does shaft work. They can tell you how bad it is, and possibly can recommend a shop to turn you a new one, which they could then grind themselves to exacting tolerances. The reason to go first to a grinding shop is that they will know the quality machine shops in the area, because they do the finishing for these shops. They will also have incredibly precise measuring devices.

From contributor D:
I own an import shaper and it works fine. I checked the runout at full extension .003.

From the original questioner:
I measure .008" at full extension just below the threads. Also at full extension, but measured at the lowest place on the spindle, I measure .004". I spoke with Grizzly's tech department this morning and was advised that this is acceptable runout! This machine has been run for less than a few hours since it was purchased a couple months ago. Im not sure what to do. I can't go without it, as I have jobs coming in right and left that are dependent upon this machine. I hate to have custom machined parts fabricated.

From contributor E:
A recurring observation through these types of postings is basically that you get what you pay for. Many individuals who have worked with starter equipment make a step up and are really impressed. But without experiencing the top of the class - shapers, t-saws, planers, etc. - one really has no idea what to compare to - other than dollars saved. If you have never used a power feed sanding machine, a double drum sander looks like heaven. If you have ever used a decent wide belt, you know the drum sander is hell.

You simply can't expect to pay $1800.00 for something that is called a shaper and expect it to be like a $10,000 machine. Exactly where the differences lie is unknown. But if you use a $10,000.00 machine, you will know where you need to aim.

If I bought a new machine and had to spend a day or so tuning it up, I'd send it back. That day will cost over $1000.00 in lost billable time. Machinery has to work for me, no questions asked - I don't work for either the machine or the machine maker. I do not want to have the machine's potential for problems to enter the equation. When I look at a shopful of equipment, reliability is extremely important. If I can't trust the equipment, then the foundation of all our work comes into question.

My advice is to send that shaper back with an invoice for your trouble. Did they explain their tolerances (and how they may differ from what is considered acceptable) to you before you bought?

From contributor B:
Regardless of what the Grizzly tech guy says, .003 to .008 is excessive and is bordering on dangerous. This amount of runout will cause a out of balance situation that will quickly ruin the bearings and possibly the bearing housing. When run at speed, the spindle will further deflect, increasing runout and vibration. Like the previous post mentioned, you get what you pay for. You don't have to spend a mint on a shaper, but do your homework. The shaper is the most versatile machine in the shop and has the potential to make you lots of money. Take it back. I checked my SCM and Oliver last night. The SCM had .001 total runout and the Oliver had .0014 on a 8.0 spindle and it's 50 yrs old.

From contributor B:
I also work in a very precision shop. .001-.003 runout is about the max on a shaper turning a 3- 5 pound cutting head. Try slowing your machine down, and make sure your knives are balanced well. A decent machine shop may be able to straighten a bent spindle. Hopefully you're not trying to run 5" tall heads, or even 2" heads with spacers under them. Once we were having trouble with excessive vibration on a shaper and the problem turned out to be spacers that weren't surfaced parallel. The local machine shop trued them for us, and this cured that particular problem.

From contributor C:
I doubt the spindle is bent because they are hard to bend, and if you bent it you would know it. We don't even know what kind of spindle it is, whether it is tapered or shouldered. If it's tapered, and removable from the top, it could easily be that there is a chunk of grit or something preventing it from seating properly. At any rate, it either has to come out, or you have to get a new machine or spindle and quill from Grizzly, or get your money back.

My choice would be the latter, if I had bought it through a local dealer. Most states have small claims courts where you can sue the local shop for about a $25 filing fee, and represent yourself without a lawyer. When you win, which you will if it even gets that far, they will have to pay the fees, and return your money. Then buy a used Italian shaper if you can't afford a new one.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor T:
I routinely make new spindles for my equipment due to bearing failures, damaged shafts etc, and I can tell you for a fact that .008 runout on 6-8" is way too much. You should be well within a .001 - .0015 range. You will have vibration and all kinds of other problems with that kind of a runout. Any good machine shop can make you a higher quality spindle than the one you have. This is the sole reason I have my own machine shop in my wood shop. It pays for itself daily.

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