# Let’s get my RF Clone running as it should!



## HuD_91gt (Feb 8, 2022)

Hey guys,

I’ve posted a few threads and everyone has been a great help.

I bought a ZAy7045fg/1 mill (RF45 clone) used for likely way too much money, and not working.  It was extremely dirty, and had an electrical issue.

After lots of help from some electrical gurus, I got it up and going after what ended up being a blown transformer.

I then tried milling some steel and found the machine had a rediculous amount of chatter.  I replaced the spindle bearings with new off the shelf Japanese units.

I tried milling again, and was still coming across what I found to be way too much chatter but it was reduced.   Spindle runout was in the way of 0.0003-0.0004 as opposed to 0.001” that is was before.

I then trammed the head in the horizontal direction. Over a 12” swing, it was out about 0.040”.   I got this down to about 0.001” over the same period. This helped tremendously.  I do notice the head could be trammed (tilt) forward and back, but that is a little deeper then I want to go right now.

I’m still finding there to be too much chatter from what I’ve seen in videos. I can mill some aluminum with a 1/4” end mill, facing the edge of a block. Taking .100” depth of cut, and about 1/2-1/4” the width of the bit.   The machines head vibrates like a palm sander.  When I go to steel, it gets some worse.

The gibs are likely over tight and locked to try and mitigate the problem. The surface finish is garbage. My bandsaw has a similar finish. I tried using a single point fly cutter(image below, aluminum),   3/4” endmill and some small end mills. No finish is great. This is the same for aluminum, steel and tried 304L as I need to face some tubing

The tooling I’m using is used. I have a box full but likely most of it is junk. I ordered a new HSS set (Chinese, accusize) which arrives today.

I’m curious if anyone anyone has more suggestions.  It definitely seems like the vibration is certainly in the head area.


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## HuD_91gt (Feb 8, 2022)




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## HuD_91gt (Feb 8, 2022)




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## pontiac428 (Feb 8, 2022)

Clear the chips from the spindle bore with a rag every time you remove the tool holder.  Clean any packing grease or cosmolene from your gibs.  Replace any chintzy gib locking levers with good ones (Kipp).  Torque then loosen 1/4 turn and re-torque your collet nut.  Ball bearing collet nuts help, and chinese BB nuts are better than chinese non-BB nuts.  Check the inserts on multiple-insert cutters on a height gauge.  Sometimes one tooth can be low from debris or sloppy import tolerances.  Loosen 1/4 turn and re-torque insert bolts.  I'll assume since you replaced the spindle bearings that you got everything torqued and preloaded right.  Something in the geared head may be eccentric or crooked.  Lock the spindle travel when cutting, of course.  These are the things I do when I get a bad finish, picked up from experience.  These machines have quirks, but can do very good work.  Keep at it!


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## HuD_91gt (Feb 8, 2022)

I’ll definitely use some of those techniques.   All my cutters are either brazed. But drinks on for testing I think I will use my new HSS bits, which should arrive shortly.

As for preload… I don’t have a manual. I did read someone say all the way right, then backed off 1/8” of a turn. The top bearing did not slide on the spindle, rather it had to be pressed off, and back on. So I honestly don’t think the “lock” nut is doing much. But I did as described.  Tightened all the way down (reaches the bearing, then stops) then back off 1/8” and lock a tab in place.  The spindle now gets warm to the touch, but not hot (1500RPM, max).

The tightening and loosening of the collets/spindle technique is a good one. Is there proper torque for this? I’ve read “monkey right, not gorilla tight.”  So I’d say they are quite tight but I’m not stretching any bolts “I don’t think”.

cheers. Will post again with some new results.


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## HuD_91gt (Feb 8, 2022)

I cleaned all bores, torqued and retourqed.   Installed new 3/4” end mill and did a light facing cut on 3/4” aluminum.   Still a lot of vibration and you can feel the chatter marks with my finger nail. The part on the left was without lubricant, right side with alcohol.

previously I took out all the guns and cleaned them up which really helped with the smoothness of the table. After testing this piece. The head started making an awful squealing noise. I guess I’m taking the spindle out and investigating.   It only did it at high RPM


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## HuD_91gt (Feb 8, 2022)




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## HuD_91gt (Feb 8, 2022)

I was just reading a post where someone actually sanded the spindle shaft down to get the proper fit (the bearing slides on) and can then be properly torqued.  I’m just assuming the squeaking noise I just started getting is the bearing, I guess we will see.


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## mikey (Feb 9, 2022)

Whoa, hold on. Please do NOT go sanding your spindle down. The bearings are a light press fit for a reason. If you used decent replacement bearings (hopefully an ABEC or P-rated bearing) and preloaded them correctly then you should have somewhere in the neighborhood of 0.0002" TIR spindle run out or less. I am not familiar with the bearing arrangement inside your head so if you can post a pic of the IPB for us, that would help. 

Insofar as preload is concerned, touching the nut to the bearing and backing off means you have zero preload ... zero. This does nothing for you and may be the source of your chatter. There is no recipe for preload on these machines but the process many of us use is to bring the preload nut into contact with the bearing and then snug it firmly, not overly tight. Then check the temp of the upper and lower spindle bearing with an infrared thermometer to ensure that bearing temps do not go above about 100 degrees C (75-80 deg C max is better). 

If you used tapered roller bearings then be sure you did not fully pack them with grease. Spindle bearings should be packed to 25-30% capacity, max. The grease will distribute during break in. If you pack them full, they will overheat and likely destroy any hardening of the bearing and it may fail. 

As with all troubleshooting processes, make a diagnosis before doing anything destructive. You need to know where the chatter is coming from; there are MANY potential sources. I would begin by making sure you know what your actual spindle run out is so you have a baseline from which to make reasonable comparisons to other components. This will give you an idea of how your spindle bearings are doing and you can go from there. 

Please do not sand your spindle. While I know somebody did this, it is not the recommended procedure.


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## HuD_91gt (Feb 9, 2022)

I understand your concern.  Below is a photo of a similar mill. The arrangement is the same as mine.   The top bearing of mine was a fairly significant press fit. Meaning, the preload is whatever the position the bearing was pressed into.

the bottom bearing is pressed onto the spindle, the spindle then slides into the quill from the bottom, where I then pressed the top bearing into position, with a locking type washer and nut to set “preload”.

the bearings are of no particular grade. I had my dealer go direct to their suppliers, and none had anything besides the “standard.” They are Japanese made though. I made sure of that.   I did not pack them as tight as a normal wheel bearing. I had read those warnings.

how would one check the runout on the spindle?   Precision V blocks and a surface plate?  I’m sadly working with measurement tools down to 0.001”. So it won’t be much help. But as I said, with the current bearings the needle barely moves. Absolutely Less then half of a single line, not that that is very accurate…


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## mikey (Feb 9, 2022)

Yeah, that is the typical spindle bearing arrangement and yes, the bearings are a press fit. Still, preload is adjustable because there is play in the bearings themselves. I used angular contact bearings and there is literally no play between the bearings and the races and even those can be preloaded.

You have to keep in mind that, assuming the spindle is in good shape, the accuracy of the spindle depends on the quality of the bearings you use and the care with which they are installed. These bearings are simple to install but you do need to ensure that pressure is applied only to the race being pressed to avoid brinelling the races so pressing adapters need to be used. Personally, I would go with at least ABEC 3 or 5 bearings in a milling spindle. I don't think going beyond this is necessary but I would consider this a minimum.

In order to check run out of the spindle, you need a tenths reading dial test indicator and readings can be taken while the quill is installed in the mill. *This is all done manually, not under power*. The indicator must be held in a rigid stand; the old-style two-arm stands are best for this and you need to get the stand and indicator close to minimize extension of the arms of the stand so as to minimize any flexion anywhere. You need to make two marks with a Sharpie; one on the quill itself and one on the spindle nose. As the spindle is rotated the mark on the spindle nose will move but the one on the quill will not; that non-moving mark is your reference index mark. The tip of the DTI is inserted so it touches the R8 taper that has been cleaned of all oil and debris. Your first trial should have the tip of the DTI touching about 1/3 of the way in from the edge of the spindle.

Preload the DTI by at least 0.015" and zero the dial. Make sure your Sharpie marks are aligned with each other. Now slowly rotate the spindle from the top and make a complete revolution until you Sharpie marks align again. Check to make sure the DTI returned to zero. If it does then your set up is reliable and you can proceed. If it does not then your set up is not rigid enough and you need to fix that. Assuming the DTI returned to zero, make another single revolution but this time note the amount of positive and/or negative deviations the needle makes and if you can, use another colored Sharpie to mark where the high and low spots are. Bring the alignment marks together again and make sure the DTI returns to zero. Repeat the process to make sure the deviations are accurate. Your spindle TIR will be the positive deviation minus the negative one. I would then repeat this entire procedure by moving the tip of the DTI in to the half-way mark of the spindle taper and then 2/3 of the way in. If all three positions show the same TIR readings then you can rely on those readings.

Once you know the total run out, your actual TIR is one-half that amount so if you see anything under 0.0002" TIR then you're probably okay. If the TIR exceeds that number then the bearings are suspect.

Spindle run out is most commonly done this way; it is called static run out. You can do dynamic run out checks but that requires pretty expensive equipment not commonly found in a hobby or average pro machine shop. Static run out is fine for our purposes but it must be done in a specific manner. Bear in mind also that if you install crappy bearings then do not expect the spindle to be accurate. By that I mean if you install automotive quality bearings then expecting to have less than a tenth run out is probably not going to happen.

Once you know what the spindle run out, THEN you can evaluate anything that goes into the spindle to see if it is a contributing factor. Remember that anything that inserts into the spindle will have its own run out. So will anything that goes into or attaches to that inserted thing. For example, an R8 collet inserted into the spindle will have its own run out. So will the end mill that goes into that collet, and it is all additive. Also bear in mind that you cannot measure run out of any of these things under power. So say your spindle has 0.0002" TIR and you put an R8 collet in the spindle and measure the run out of the collet; say it shows 0.0007" TIR. Then you insert an known good end mill in the collet and it has a TIR of 0.001". Now you know that the combination of the R8 collet plus end mill is causing at least 0.0008" of run out. This might sound like its pretty good but there is evidence that for every tenth of run out of that end mill, you will have a 10% reduction in tool life so we're looking at about an 80% reduction in the life of that tool. Some folks think this isn't a big deal in a hobby shop but in my opinion, if this happens to an industrial mill then it will happen in a hobby mill, too so to me, run out is a big deal and is another reason why I think installing a decent class of bearings in your spindle is a wise decision.

I'll end this with one more thing. Many of us use decent ER chucks with good collets and good nuts for a reason. ER chucks are about the most cost effective tool holding system available to the average hobby guy. It may not be the most accurate but it is very good and it is also the industry standard for most shops. Once you get your spindle running accurately, look into a good ER system for your mill.

My personal ETM ER40 chuck in my personal spindle will hold an end mill under 0.0002" TIR and that's good enough for me.


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## HuD_91gt (Feb 9, 2022)

Thanks for the extensive explanation. It took a couple reads, but I’ve now come to the conclusion that is exactly how I tested my runout. Not quite as detailed, but the procedure was more or less the same. I need to get my hands on some more precision instruments though. As for the “old style” holder. That’s all I own .

I’m still wrapping my head around the preload on the bearings. If the lock nut, putting the pressure on the bearing, is only pressing on the inside race, which in my mind is “fixed in place due to the press fit.” How is it preloading the bearing? Unless im visualizing the lock nut incorrectly, and it’s putting pressure on the outside of the bearing (not the other race. Please ignore my ignorance.  Mechanics are far from my expertise, although I always figure them out, it’s not a trained skill of mine.  Bearings were all pressed in with machined pieces to ensure proper installation of the races. A selection of pipes and a lathe come in handy. Although it was done without a press, a lot can be done with threaded rod.

Anyhow, I’m taking it apart today to see what’s going on. If everything visually looks ok I may tighten up that bearing and see what happens. New bearings would be nice, but this “drill press” replacement (what I told my wife) is getting mighty expensive after vises, tooling, measuring equipment, bearing replacements. Haha. If I do need to replace the bearings, I will search eBay and go for something higher quality like you state.  Locally nothing was available.  

Thanks for all the help, lots of knowledgeable people here.


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## markba633csi (Feb 9, 2022)

You need to check the fit of the spindle quill to the head casting- a loose fit there would cause movement and chatter
-Mark


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## HuD_91gt (Feb 9, 2022)

Just tightened the preload nut. I still don’t understand how it preloads the nut without movement from the center race.  I think it does feel a little more stiff though, so maybe it did?
Edit: just tested the runout again using my 0.001” DI.  No detectable movement from the needle. That’s a bonus.

The squealing is coming from the auto feed gearing. A quick spray of penetrating lubricant in the area and the sound went away.

to check the tolerance of the quill/machine… bore gauge and outside micrometer?

Improvement for sure. 850RPM(also tried 1500RPM, similar maybe slightly better) . 3/4” 4 flute HSS. Light facing. Feels smooth to the touch now. But can get a much better finish in my lathe. Not sure if that’s normal??


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## HuD_91gt (Feb 9, 2022)

So latest tests.

Undetectable runout on the spindle.
Less the. 0.001” on the ER32 taper.
0.0015” on the shaft of an endmill in the collet
I get 0.003” if put horizontal force with my hand, using the collet holder for leverage against the spindle. This seems excessive? This would be the standard force the spindle sees when milling.


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## pontiac428 (Feb 9, 2022)

The measurement obtained while pushing and pulling the spindle isn't truly runout, it is deflection.  Deflection counts towards inaccuracy, but it behaves a little bit different than runout alone.

Which end mill are you using?  It's tough to tell TiNi junk from Niagara yellow gold in a photo.


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## HuD_91gt (Feb 9, 2022)

Oh yes. I know it’s not runout. But it seems excessive for pretty standard forces in my eyes.

I’m using some standard Chinese HSS made by “Accusize”.  Seem to be leaps and bounds better then the other tooling that came with the machine

“Tin Coated”



			https://www.amazon.ca/Accusize-Coated-Mills-Flute-1810-0100/dp/B01FGFFDAU/ref=mp_s_a_1_16?crid=388URV3E16Y7N&keywords=hss+accusize&qid=1644445965&sprefix=hss+accusize%2Caps%2C135&sr=8-16


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