# Question on mill/drill traming.



## SonofHarold - Metal Carver (Mar 5, 2019)

I'll try and keep this short but a little back ground. I have one of the older HF round column mill/drills. ( model 24976)I know it has it's limitations but I am trying to get it to be as good as it can be.  Finally got the spindle/quill re worked, and a simple DRO to have something for measruing the Z ( it had nothing) so it's time to dial it in and get everything square. 
The other night I cut some shims and was just going to get started and see just how hard or fussy it was going to be and to my surprise it was much closer than I expected. 
So I started trying to make it better. Ended up chasing the indicator around for more than two hours and a couple dozen different shim combinations.  Made it a lot worse at times but the best I could get was within about .003-.004. I was using an indicator and a new disc brake rotor placed on the table and sweeping about a 10.5 inch circle. Question is; should I expect it to get much better with this machine? I was working alternately on both the side to side and the front to back and was kind of chasing it in and out a lot.... Right now fairly well snugged up it's off about 3 and half thousands on the Y and about 2 thousands on the X. It that as good as it gets or do I need to drink a big cup or patients and go back at it?
Thanks-


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## Norseman C.B. (Mar 5, 2019)

Personally I would dial it in on it's own table surface, that would take out any error from the disk........................My .02


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## Technical Ted (Mar 5, 2019)

Yep, I agree 100% with Norseman... just run the indicator on the table top. If it was my machine, I would like to see it within 0.001" A lot depends on what kind of work you will be doing and what kind of tooling you will be using.

Ted


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## SonofHarold - Metal Carver (Mar 5, 2019)

That has a pretty small table and sweeping across the slots seem difficult, I think I found the idea of using the brake rotor on line someplace - maybe here(?)
I did try tuning the brake rotor 90 deg thinking there was some error in it because sometime it seem pretty consistant and others not so much but the readings on the indicater were the same +- a thou.  or less.
But.... I did try going directly to the table and seems about the same as best I can tell, about .002  or a little less on the x, but sweeping acrross the slots make me question my accuracy too. Any ideas on that? guess I should take some pics of my set up.
So you would think that machine can be dialed in closer than I have it. Seems just reaching up to turn the spindle and touching the maching  can move the idicator a thou or more if I am not gentle.


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## mikey (Mar 5, 2019)

I have an RF-31 so it should be very similar to yours, John. I agree with the other guys that you should use the table surface as a reference PROVIDED it is clean and free from defects. The reason for this is that it is what we mount our vise or work to and that is what we want to tram to.

As for acceptable tolerances, there is no standard for this sort of thing that I am aware of. Most of us want zero deviation in all axes, most of us can get 0.001" or less. 

My column is trammed with precision shim stock and onion skin (precision paper shim stock). It is 0.0005" high in the front of the table and zero in all other directions. It took two days, *two days*, to get it there. I used a torque wrench set to 35 lb/ft on each column bolt to be sure that didn't mess things up and when I got the final shimming done, I loosened and re-torqued the bolts to be sure nothing changed. I admit that I haven't looked at it since so it may have changed. I'll have to go re-check it soon.


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## SonofHarold - Metal Carver (Mar 5, 2019)

So... I don't need a cup of fresh patience  but maybe I should buy a case before heading out there?  I did look around on the site a little more and found someone using 1-2-3 blocks and moving it from side to side when swining the indicator around. (?) When it warms up again some here I'll go try again, I shut down the heat a while a go out in the shop and we are going down to the teens overnite tonight so it might be the weekend before I warm up the shop again...  unless I get bored ( I am sure you have no idea what I am talking about... just looking for sympathy... jk)


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## mikey (Mar 5, 2019)

Yup, patience helps. Look at it this way. The accuracy of every single face or edge you cut on the mill is influenced by how accurate your tram is, and tolerances stack up quickly. If you cut a side and use it as a reference for the next side then it will be off a bit, then a bit more, and so on. I figure its worth the effort it takes to get it right and then do what it takes to keep it right. 

I used a Starrett back plunger indicator to get tram really close. The tip slides over the slots so its easy. Once I got really close, under a thou, I switched to a Compact 215GA tenths indicator and moved carefully over the slots to avoid damaging the indicator. Two days of that taxed my patience but I did it because it matters. 

What is really frustrating is when I move the head, all that careful work goes out the window. We don't actually lose tram when we move the head; we lost that centered position from which tram was set. If we can return to that exact position the mill will be in tram again so the trick is to get it repositioned again. Bruce Witham of Australia came up with the True Line 88 to do exactly that. Others have used linear shafting to do the same thing, or laser pointers. I bought a True Line 88 to see if it does the job and when I have the time, I'll install it and review it for you guys here. 

Unlike you, time is my issue. It is currently 76 degrees with a cool 17 mph Northeast trade wind so I'm comfy but don't have the time to tear into my mill right now. Is there such a thing as a gonad-warmer?


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## Norseman C.B. (Mar 5, 2019)

That tru line looks interesting. 
I'm wondering if the UHMW will hold tolerance over time, I've made lots of 
industrial roller shaft bearings with it but they do wear quicker than bronze the trade off being
cheaper to replace, maybe over thinkin here.......................


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## Bob Korves (Mar 5, 2019)

SonofHarold - Metal Carver said:


> So... I don't need a cup of fresh patience  but maybe I should buy a case before heading out there?  I did look around on the site a little more and found someone using 1-2-3 blocks and moving it from side to side when swining the indicator around. (?) When it warms up again some here I'll go try again, I shut down the heat a while a go out in the shop and we are going down to the teens overnite tonight so it might be the weekend before I warm up the shop again...  unless I get bored ( I am sure you have no idea what I am talking about... just looking for sympathy... jk)


I do not like to use intermediate blocks of any kind when indicating something.  Everything has a tolerance, is not flat or parallel, and using them as intermediates only confounds the readings.  Use an indicator right on the table, and have it set up so the plunger can only go into slots or dings a few thou.  Yes, it will bounce around some, but it will be measuring reality.


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## mikey (Mar 5, 2019)

Norseman C.B. said:


> That tru line looks interesting.
> I'm wondering if the UHMW will hold tolerance over time, I've made lots of
> industrial roller shaft bearings with it but they do wear quicker than bronze the trade off being
> cheaper to replace, maybe over thinkin here.......................



To be honest, I don't move the head much thanks to the 5" of quill travel but it does move from time to time. What I want from the TL88 is for it to return me to my centered position, nothing more. Since it will see limited travel and limited use, I suspect the use of Delrin or UHMW material is a good choice. The vertical bar that travels through it is an accurately squared aluminum rectangular bar that is bolted to a bracket fastened to the side of the head and the Delrin block is anchored with a machined steel collar at the bottom. There is a hole in the Delrin that allows you to use a tensioning bolt to draw the sides of the channel tighter if needed.

All this thing needs to do is guide the head reasonably straight up and down and then allow the head to center accurately once the head bolts are tightened. My criteria for acceptable performance is for it to restore the head to centered position within a thou or less. If it does that then it is worth it. 

I won't lie. I can easily make one of these contraptions but Bruce spent the time, effort and money to come up with this thing. I spent the money on it because it was the right way to do this and also because I wanted to review it for the HM membership. Since I bought it, I feel free to do an honest review, which I will do.


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## darkzero (Mar 5, 2019)

mikey said:


> I bought a True Line 88 to see if it does the job and when I have the time, I'll install it and review it for you guys here.



Awesome, looking foward to it even though I don't have a round column. Take your time but hurry up! 



mikey said:


> My column is trammed with precision shim stock and onion skin (precision paper shim stock). It is 0.0005" high in the front of the table and zero in all other directions. It took two days, *two days*, to get it there. I used a torque wrench set to 35 lb/ft on each column bolt to be sure that didn't mess things up and when I got the final shimming done, I loosened and re-torqued the bolts to be sure nothing changed. I admit that I haven't looked at it since so it may have changed. I'll have to go re-check it soon.



Haha, I think it took me like 4 days! 1 whole day to figure out how to support the head & column to insert & change the shims everytime. I used precision shim stock also. I got mine down to .0007" (low in the front) but I can manipulate it depending how much I tighten the head locks. Mainly it's the top one that affects it.

I just retrammed last week (tilt). Been years since put those shims in there and the nod is still the same from what I remember. My guess is yours hasn't moved either. I'm going to reshim again though, making sure the column gib is adjusted nicely first.


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## Aukai (Mar 6, 2019)

The guys in America don't feel bad for how cold it is here lately. Looks like a ski resort without snow with everybody bundled up around here. It's almost in the 50s in the morning, and doesn't get above 75 till the afternoon. OK back to regular programming.


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## mikey (Mar 6, 2019)

Brah, when these guys are seeing -50 degrees, we'll get no sympathy when we complain about +50 degrees! Let's you and I just enjoy where we live and quietly feel sorry for those frozen guys.


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## Aukai (Mar 6, 2019)

Ya think, well maybe some.....But they do have heaters too.


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## mikey (Mar 6, 2019)

darkzero said:


> Awesome, looking foward to it even though I don't have a round column. Take your time but hurry up!



I'm gonna' indicate the head so I'm sure it is dead on center first, then re-check tram to make sure its good, then install the TL88. May take a little while - my project list is HUGE and I am waay behind.





darkzero said:


> Haha, I think it took me like 4 days! 1 whole day to figure out how to support the head & column to insert & change the shims everytime. I used precision shim stock also. I got mine down to .0007" (low in the front) but I can manipulate it depending how much I tighten the head locks. Mainly it's the top one that affects it.
> 
> I just retrammed last week (tilt). Been years since put those shims in there and the nod is still the same from what I remember. *My guess is yours hasn't moved either*. I'm going to reshim again though, making sure the column gib is adjusted nicely first.



God, please let Will be right!


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## darkzero (Mar 6, 2019)

Aukai said:


> The guys in America don't feel bad for how cold it is here lately. Looks like a ski resort without snow with everybody bundled up around here. It's almost in the 50s in the morning, and doesn't get above 75 till the afternoon. OK back to regular programming.





mikey said:


> Brah, when these guys are seeing -50 degrees, we'll get no sympathy when we complain about +50 degrees! Let's you and I just enjoy where we live and quietly feel sorry for those frozen guys.



It got down into the 30s 2-3 weeks ago, that's not normal for sunny SoCal! Well it happens every 4-5 yrs. It snowed here last week where it never snows. I didn't actually see it though.

Reminded me of this video about it.


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## darkzero (Mar 6, 2019)

mikey said:


> May take a little while - my project list is HUGE and I am waay behind.



I can relate, it only took 2 years to get my Yuasa round mag chuck mounted & only 4 yrs for my TS DRO! 
	

		
			
		

		
	






mikey said:


> God, please let Will be right!


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## Buffalo21 (Mar 6, 2019)

I’ve used a brake rotor years, when I finish up, I rotate the rotor, 90 degrees, resweep and recheck the readings, I’ve never had to change a thing, some readings.


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## ThinWoodsman (Mar 6, 2019)

Aukai said:


> The guys in America don't feel bad for how cold it is here lately. Looks like a ski resort without snow with everybody bundled up around here. It's almost in the 50s in the morning, and doesn't get above 75 till the afternoon. OK back to regular programming.



Ten or so years ago, I went to visit an ex-pat friend living in Thailand. It dipped below 70F there one weekend, and all the young kids were out in the winter gear they'd inexplicably purchased and had been waiting for a chance to wear.

Same guy was telling me a story of explaining to a local (obviously not a very bright one) that houses in other places have heaters as well as air conditioners. "But why would you heat up a room when you're just going to have to use the A/C to cool it down again? Isn't that wasteful?"

Yeah, I kinda prefer having seasons. It passes the time


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## SonofHarold - Metal Carver (Mar 6, 2019)

Dropped the brake rotor and tried in directly, I think I also get a better more solid rig for holding the indicator. Do the pics look like the set up is OK? or should the indicator be at a lower angle more parallel to the table? At this point with out too much trouble I have it within a thou to a thou and a half (0.0015) the greatest error is in the nod (Y) and it tends to be low in the front. I notice it does not take much to push the head up/back a little and take out that error and figure any cutting is going to tend to push it in that direction anyway -(?) that is the .0015 and the largest difference as I sweep around. Big question is if my set up is OK per the pics? Thanks again! How about the set up for the vise?


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## ThinWoodsman (Mar 6, 2019)

SonofHarold - Metal Carver said:


> Big question is if my set up is OK per the pics? Thanks again! How about the set up for the vise?



I'll let others speak more definitively on this, but right off the bat I would suggest making the indicator holder more horizontal (which entails lowering the quill towards the table) so you can sweep a greater distance. You want the greatest distance possible between the two points you are comparing (one to the left, one to the right of the spindle)


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## SonofHarold - Metal Carver (Mar 6, 2019)

darkzero said:


> Awesome, looking foward to it even though I don't have a round column. Take your time but hurry up!
> 
> 
> 
> ...


I checked out that True Line Kit, and found the Price at $400+ with shipping to be a little pricey. I am not sure my HF Mill Drill is even worth that much as it sits now.


mikey said:


> To be honest, I don't move the head much thanks to the 5" of quill travel but it does move from time to time. What I want from the TL88 is for it to return me to my centered position, nothing more. Since it will see limited travel and limited use, I suspect the use of Delrin or UHMW material is a good choice. The vertical bar that travels through it is an accurately squared aluminum rectangular bar that is bolted to a bracket fastened to the side of the head and the Delrin block is anchored with a machined steel collar at the bottom. There is a hole in the Delrin that allows you to use a tensioning bolt to draw the sides of the channel tighter if needed.
> 
> All this thing needs to do is guide the head reasonably straight up and down and then allow the head to center accurately once the head bolts are tightened. My criteria for acceptable performance is for it to restore the head to centered position within a thou or less. If it does that then it is worth it.
> 
> I won't lie. I can easily make one of these contraptions but Bruce spent the time, effort and money to come up with this thing. I spent the money on it because it was the right way to do this and also because I wanted to review it for the HM membership. Since I bought it, I feel free to do an honest review, which I will do.


I looked at those also but at $400 (?) I am not sure my mill is worth it. I'd be happy to get much more than that for it as it sits. I only paid I think about $200-$250 for it from a friend who did much of the mods; power X feed and a DC variable speed drive motor. But I'll look for the review when you post it.


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## SonofHarold - Metal Carver (Mar 6, 2019)

ThinWoodsman said:


> I'll let others speak more definitively on this, but right off the bat I would suggest making the indicator holder more horizontal (which entails lowering the quill towards the table) so you can sweep a greater distance. You want the greatest distance possible between the two points you are comparing (one to the left, one to the right of the spindle)


I understand a larger arc results in more accuracy.  I set it there as the width of the table limits me, that set up sweeps within about 1/8" of each edge of the table which is only about 6" wide. I was trying to get both X and Y with one indicator set up. That is part of the reason I had been using the brake rotor which gave me about a 10 Inch circle... My main question here is the indicator itself accurate at that angle?


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## mikey (Mar 6, 2019)

SonofHarold - Metal Carver said:


> ... should the indicator be at a lower angle more parallel to the table?  Big question is if my set up is OK per the pics?
> 
> How about the set up for the vise?



The tip of the indicator is at too large an angle. This will introduce Cosine errors that will give you false readings. The indicator arm needs to be nearly parallel to the table surface. A quick search turned this up:https://www.cnccookbook.com/cosine-error-indicator-measurements/

You should also lower the quill and stretch out the indicator holder arm to give you more reach. The larger the sweep, the more sensitive the readings will be. 

The vise set up looks fine.


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## mikey (Mar 6, 2019)

SonofHarold - Metal Carver said:


> I checked out that True Line Kit, and found the Price at $400+ with shipping to be a little pricey.



Gotta' agree with you that the kit is pricey and I don't think he'll sell too many because of that. If it works, the result will be that folks will just quietly pirate the idea and make their own. The kit is intended for older mills that are just not worth the cost. Moreover, the problem it seeks to solve is not a major one so the price is too high.


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## RJSakowski (Mar 6, 2019)

One practice that I use when moving the head on my round column mill/drill is the snug up the center nut first.  The I snug the top and bottom nuts.  I then repeat the procedure a second and third time with the last time being to fully tighten all three nuts.  

The reasoning being that if you tighten the nuts in a single operation, there is the possibility of resulting friction capturing a bias and skewing the head.

I did check to see if the tightening sequence affected tram and there was some difference but it was under .0005"/6".


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## mikey (Mar 6, 2019)

Is you mill drill a HF model? All the Rong Fu mills have two bolts only, although I think three would be better.


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## SonofHarold - Metal Carver (Mar 6, 2019)

mikey said:


> The tip of the indicator is at too large an angle. This will introduce Cosine errors that will give you false readings. The indicator arm needs to be nearly parallel to the table surface. A quick search turned this up:https://www.cnccookbook.com/cosine-error-indicator-measurements/
> 
> You should also lower the quill and stretch out the indicator holder arm to give you more reach. The larger the sweep, the more sensitive the readings will be.
> 
> The vise set up looks fine.


Doing a little mental gymnastics on this... just want to make sure I'm thinking of this right....
Looking at the graphic on the cnccookbook site and if that is represented correctly for the example - the position of the indicator itself is at the same angle (0) and it is the angle of the tip in relation to the indicator which creates the error, or is it the angle of the tip to the surface being measured without regard to the angle of the indicator itself. The tip on mine has a ratchet or detents and can be postioned through more than 180 degrees in relation to the indicator. This is the only DTI I have, It is a Federal Testmaster. Do all lever type indicators have that feature?


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## SonofHarold - Metal Carver (Mar 6, 2019)

Just located a PDF of an instruction sheet For my old DTI which answers my questions and has a table with a correction factor for various angles. More Tramming practice tomorrow. THNX!
Adding:  thanks for the Ref to the CNCcookbook site! Never spent much time there cause I'd see the CNC and didn't think much there would apply to me. Looks like there is a lot of good info there tho. It is now bookmarked. You know I do love learning new stuff!


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## mikey (Mar 6, 2019)

It's the angle of the tip that matters. Position the body the way you want but get the tip near level for that indicator. All DTI's should be able to do this.


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## SonofHarold - Metal Carver (Mar 6, 2019)

darkzero said:


> It got down into the 30s 2-3 weeks ago, that's not normal for sunny SoCal! Well it happens every 4-5 yrs. It snowed here last week where it never snows. I didn't actually see it though.
> 
> Reminded me of this video about it.


I was stationed up at Edwards AFB near Palmdale in the 70's and it snowed once, about 3-4 inches. Seems it hit all at once and I was in a truck out near the end of one of the runways near the dry lake. Visibility went to what seemed like near zero with no refferences out there anyway drove down the taxiway feeling when the right side wheels would drop off the pavment going like 15 mph to find our way back to the parking ramp and our hanger. Fun times! They closed the base and we all got to go home for the day.


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## yendor (Mar 7, 2019)

One more thing to consider is you are using a drill chhuck to hold your indcator.
the drill chuck will have it own runout that will add error to your process.

I used a grizzly indictor holder that clamps onto the quill and doesn't introduce additional error.








						Universal Indicator Holder at Grizzly.com
					

Mount your dial indicator right on your milling machine for guaranteed accurate readings. C-frame holder mounts with a single screw directly on the machine's quill and does not interfere with the cutting tool. Clamping diameter is 1-7/8". The length from clamping bracket to indicator is 4-1/2"...




					www.grizzly.com
				




Its on sale right now for $11.99 (-$4.00)
It worked great for me.


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## SonofHarold - Metal Carver (Mar 7, 2019)

I did buy one of the holders lke those, (as I'd saw one before being used on a bridgeport) without measureing, and it is too small and will not fit my quill by about 1/4" I have ordered the correct size collett tho to hold the indicator. If I am calculating the error from the angle correctly (which makes my driret reading from the indicator smaller(?) I think I have it all within about a thou tho at this point. That said I may just wait for that collet before I go and do anything more... Thnx


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## Technical Ted (Mar 7, 2019)

yendor said:


> One more thing to consider is you are using a drill chhuck to hold your indcator.
> the drill chuck will have it own runout that will add error to your process.



Sorry, but I have to disagree unless I'm misunderstanding what you mean. Clamping up on an indicator mount in a chuck or something else that runs out will not effect the accuracy of the reading. You can also use an edge finder in a 3 jaw chuck that runs out and it will be accurate.

You could use a mag base and attach it to the side of the chuck and it would work just fine also.

I do love those holders though. I have an Indicol and use it all the time!

Ted


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## SonofHarold - Metal Carver (Mar 7, 2019)

I was kind of second guessing about the chuck throughing out at least the measurement I was trying to get and being a new to this thought I was might be missing something. I know a drill chuck is not a supper accurate way to hold things... .but I want to have a 1/4" collette anyway
(hi my name is John and I'm tool addicit)
But I am now declaring a success and Much Thanks and Kudos being due!  It was a good learning experience regarding the details of using a Test indicator plus I got my mill/drill trammed to a closer tollerance than I thought would be possible, along with a fair amount ot practice getting the vise on and off and trammed as well, which is pretty easy now. Got the indicator to a postion with an angle that was about 20 - 25 degs and a little larger sweep circle as well.  Applying the correction factor for a 30 degree angle ( from the Federal instruction sheet I found) and it is within a thou all the way around. Close to only half a thou in the tilt and just shy of a full thou in the nod front being the "high" point. I also tried it again with the brake rotor and it was about the same, turned the rotor 90 and still the same. I then undid everything, set it all up again from scratch and still +- .001 or less.
Thanks everyone but especially Mikey,TT and Norseman! Yinz all try and stay warm...


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## mikey (Mar 7, 2019)

Glad you got it sorted, John. It is a royal pain to do this but necessary.


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## darkzero (Mar 7, 2019)

Technical Ted said:


> Sorry, but I have to disagree unless I'm misunderstanding what you mean. Clamping up on an indicator mount in a chuck or something else that runs out will not effect the accuracy of the reading. You can also use an edge finder in a 3 jaw chuck that runs out and it will be accurate.
> 
> You could use a mag base and attach it to the side of the chuck and it would work just fine also.
> 
> ...



Yep. Indicator is logical, doesn't matter what it's mou ted to or held in cause it's spinning on the spindle axis. When I first heard about using in edge finder in a drill chuck with runout I didn't understand it or believed it until I tried it. It was just as accurate in a drill chuck that had .003 runout as it was in a collet.

But what is affected are the electronic contact type edge finders. Those matter cause you don't use them spinning. I use one when I don't want to mar a finish.

Still I always use edge finders in a collet though. I also love holders and enjoy using my Nogas.


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## RJSakowski (Mar 7, 2019)

mikey said:


> Is you mill drill a HF model? All the Rong Fu mills have two bolts only, although I think three would be better.


That's an interesting question.  The mill was private labeled by a local DIY.  I can't find the nameplate butI am quite sure it was a Taiwan machine.  Thr user manual calls it a JP-30 but inside, it is referred to as an RF-30.  There is an anomaly though.  The table is speced as  8-1/4 x 28-3/4 but actually measures 9-1/2 x 23-1/3.  It has a 2 hp motor and the column diameter is just over 4".  I purchased it around 1980.


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## mikey (Mar 7, 2019)

Doesn't really matter, RJ. I just noticed that the HF-sourced mills have three bolts and the RF models have two. Personally, I would rather have three bolts.


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## yendor (Mar 8, 2019)

Hmmm... apparently I stand corrected and that's not a bad thing.
It always good to learn something. I was thinking someting with it's own built in error would pass that same error onto an indicator but it seems not.

I'm going to have to go try this myself but only for satisfaction purposes. 
I suspect you guys have much more knowledge than me.
I've got a LOT to learn still... (just ask my wife


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## SonofHarold - Metal Carver (Mar 15, 2019)

SonofHarold - Metal Carver said:


> I did buy one of the holders lke those, (as I'd saw one before being used on a bridgeport) without measureing, and it is too small and will not fit my quill by about 1/4" I have ordered the correct size collett tho to hold the indicator. If I am calculating the error from the angle correctly (which makes my driret reading from the indicator smaller(?) I think I have it all within about a thou tho at this point. That said I may just wait for that collet before I go and do anything more... Thnx


OK. Got the collet to hold the indicator rather than the 3 jaw. rechecked it all around, and after doing just a couple of practice type, making swarf cuts it looks to still be in the +-0.001, Even after raising the head a bit on the column. I am happy that its going to stay but I'll be rechecking in several months just to up my confidence, Again - thanks for every ones help!


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## mattgray_calif (Aug 27, 2021)

RJSakowsky, you probably figured it out already, but your JP-30 might be a Jia Piin JP-30.  Example faceplate in this reply.  Do you happen to know the spindle taper of yours?  MT3 or R8 perhaps?


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