What are the odds of getting two bad arbors?

[mksj]

Actually I think the odds are quite high, when you consider that it is a production run and the distributor often will get stock from the same batch. I have seen the same issue with Dorian in the past with regard to their QCTP and holders, let alone they kept changing the design of their holders. When they put together their kits, it was whatever they had on hand. I considered buying a Sierra America Arbor, they weren't inexpensive and I recall similar reports to high runout (TIR), and I did not want to fork out $$ for their high precision saw arbor line. I made my own and the TIR was about 0.001" and the holder cap to arbor clearance is a close fit (0.0005") that it holds the saws very true. I might suggest you call the company directly as they state they have a "limited" 5 year warranty.

General Purpose Reach Arbor SA-3L (Set - .625-.1.000-.1.250 dia)

Description Set includes one of each: SA-625, SA-1000, SA-1250 Most accurate general purpose arbor sold .001 SQUARE shank to cutter locating area “VIBRA-CORE DESIGN” allows for most cutter vibration to be absorbed through our special heat treating process Deep low profile caps g

sierraamerican.com

 

[Jim F]

Some time, I will do that. My first one was a failure. I really am not quite sure what went wrong. All I know is I hit the cap dimensions "perfectly" and the saw just fits. But the cap interferes when inserting part way into the arbor, and I couldn't figure out where it is hitting. I strongly suspect a boring issue, or even a taper issue. At the time, I was not proficient or knowledgeable enough to determine the problem.

I have only about 1 yr running my lathe and mill/drill.....

 

[WobblyHand]

Is it only the counterbore that is off-center, or is the hole for the bolt off center too? If the former, I'd just widen the counter-bore to give the bolt clearance. A too-large counterbore isn't going to cause a problem until it gets really big.

If the bolt hole is too large, you might get away with enbiggening it too, as long as you don't have to make it big that the bolt head goes through it (though even THAT could be fixed with a washer).

I think the cap and the holes in it are fine, but I will indicate it tomorrow.

Pretty sure the hole in the arbor body is not on centerline of the spindle. That is what it looked like with arbor #1. The hole is straight, but not on centerline of the spindle axis. It is like it was removed from one machine or fixture and placed in another fixture, and there is an offset error.

 

[WobblyHand]

I have only about 1 yr running my lathe and mill/drill.....

Apparently you are very talented. My hat is off to you

 

[ErichKeane]

I think the cap and the holes in it are fine, but I will indicate it tomorrow.

Pretty sure the hole in the arbor body is not on centerline of the spindle. That is what it looked like with arbor #1. The hole is straight, but not on centerline of the spindle axis. It is like it was removed from one machine or fixture and placed in another fixture, and there is an offset error.

Ah, well, even this doesn't really matter as long as the cap can bolt in/be used as a clamp, the critical dimensions are:
1- the cap's inner diameter piece is a very close fit to the inner diameter of the body.2
2- the body's inner diameter's runout.

Everything else just has to be a 'clamp' for the cutters.

 

[benmychree]

As mentioned above, the cure is to bore out the counterbore and the body fit for the shank of the screw, and get on with your job.

 

[WobblyHand]

Ah, well, even this doesn't really matter as long as the cap can bolt in/be used as a clamp, the critical dimensions are:
1- the cap's inner diameter piece is a very close fit to the inner diameter of the body.2
2- the body's inner diameter's runout.

Everything else just has to be a 'clamp' for the cutters.

As I have mentioned before, these arbors are fixable. On my "freebie" I will fix it. I'm inclined to fix arbor #1 by boring the hole in the arbor body true and rethreading with a larger screw. Or I could play around with the cap and enlarge the counterbore. Either would work, with your suggestion being easier.

But, honestly, I don't feel that I should be expected to accept this second defective arbor and have to pay for it. (I didn't contract for a defective arbor. I paid for a new, serviceable arbor that would hold the saw blade true.) Neither arbor #1 nor arbor #2 should have been shipped to McMaster, or to me. I will call Sierra American next week. They seem to have some sort of problem that is letting these parts get shipped. The arbors I received are not up to quality standards. One should be able to tighten the screw all the way into the arbor without binding or interfering with the counterbore, especially if the binding can cause the saw blade to not run true.

 

[ErichKeane]

As far as 'should you get something like this', the answer is obviously 'no'. The fact that you got 2 is probably as others said, a bad production run, someone asleep at the CNC machine A call to Sierra would be nice to at least alert them of their mistake, perhaps they can get the rest off the proverbial shelves. That said, I'm immediately disappointed in their QC, and probably am going to mentally consider them about equivalent to 'chinesium' products.

 

[WobblyHand]

As mentioned above, the cure is to bore out the counterbore and the body fit for the shank of the screw, and get on with your job.

The arbor is fixable, both of them are. Fixing the arbor is not the point of the thread.

I do not accept paying full retail price for defective equipment whether I can fix it or not. It is the principal of it.

As an example, would you accept delivery of a car that you paid MSRP without the rear axle and wheels? You paid for a full vehicle and expect full function for that price, wouldn't you?

 

[mmcmdl]

What size saw is that for ?