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RF-40 with DRO

DavidR8

DavidR8

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If you can stomach the price...$2750.
I looked at this machine last year when I was looking for my mill. Was priced at $2800 then IIRC.
Since then owner added a DRO.
https://www.usedvictoria.com/classified-ad/Milling-Machine-with-DRO_36222727
Screen Shot 2020-08-13 at 9.48.43 AM.png
 
If it's in good shape what is it worth? The DRO is what, $300ish? Looks like a newer motor, Baldor.
 
YotaBota said:
If it's in good shape what is it worth? The DRO is what, $300ish? Looks like a newer motor, Baldor.
Click to expand...
I think more than $1800 is too much to be honest. It has a geared head but it's still a round column mill, same as mine. I paid $1300 for mine.
My DRO which looks virtually identical was $306 so the math doesn't work out. He's deducting $750 for the DRO.
Here's pics from Feb of this year.
https://www.hobby-machinist.com/threads/1-4-of-the-way-to-a-mill.82188/post-716223
 
@David_R8 Now that you've had your mill for a while, how do you feel about the Morse taper spindle? It seems to me that R8 stuff is a little more common. Is the MT spindle a drawback or is it a non-issue in practise?

BTW, I guess the seller ascribes to the Barnum Bailey theory: "There's a sucker born every day!"

Craig
 
trlvn said:
@David_R8 Now that you've had your mill for a while, how do you feel about the Morse taper spindle? It seems to me that R8 stuff is a little more common. Is the MT spindle a drawback or is it a non-issue in practise?

BTW, I guess the seller ascribes to the Barnum Bailey theory: "There's a sucker born every day!"

Craig
Click to expand...

I have no issues with it.
I use an ER32 collet and your MT3 collets (which are great by the way) for milling work and a pair of MT3 drill chucks for making holes. I found a Criterion boring head with a straight shank which was a bit of a score.

I can find most tooling I need with a straight shank so I can use it in one of my two collet options.


Sent from my iPhone using Tapatalk
 
The biggest downside to MT3 spindle is it lacks repeatability when clamping down - not too big a deal, actually. Changing tools always resets your tool length anyway. They can be a little tough to release, especially if you have used a face mill, and clamped down real hard. Morse tapers get tighter in use.
 
Dabbler said:
The biggest downside to MT3 spindle is it lacks repeatability when clamping down - not too big a deal, actually. Changing tools always resets your tool length anyway. They can be a little tough to release, especially if you have used a face mill, and clamped down real hard. Morse tapers get tighter in use.
Click to expand...
Being new to milling machines I've been surprised how light of a tap it takes to release tooling from the holder. I had read about hammer integrated wrenches for the drawbar and how whacking on the top of the drawbar is often a necessity. I have not experienced that yet...I am assuming that is because I have an R8 collet. Maybe I'm also not tightening things up enough???
 
DPittman said:
Being new to milling machines I've been surprised how light of a tap it takes to release tooling from the holder. I had read about hammer integrated wrenches for the drawbar and how whacking on the top of the drawbar is often a necessity. I have not experienced that yet...I am assuming that is because I have an R8 collet. Maybe I'm also not tightening things up enough???
Click to expand...

I have had to use a mallet to release my ER32 collet chuck from the mill.


Sent from my iPhone using Tapatalk
 
All of my equipment is MT3 so don't have an opinion on "what is better".
The lathe tail stock MT3 isn't "drawbar pulled tight" and it releases easily every time, just cranks up against the internal threaded rod and pops out. I have only ever had it 'remove itself from the socket" once during use, I was enlarging a hole in a brass shaft with a twist drill and it "bit" enough to pull the spud away from contact. I was very worried that I had screwed the socket when the spud started turning with the chuck but it pulled far enough out the instant it grabbed that there wasn't even a scuff mark visible inside.

My mill is drawbar equipped of course and I snug firmly when installing drill chuck or collet holder. I always just loosen the drawbar a thread or two and then have to "sharply whack" the drawbar head to loosen the spud before unwinding the rest of the threads. By "sharply whack" I mean hard enough to flare the hex head a little ( requires a trip to the grinder every couple years to remove the fold-over lip). In 15 yrs I haven't (other than the flare) notice any adverse damage from this treatment....never had a spud turn in the socket neither, I think the belts would burn or the motor stall out before that happened.
 
I use MT3 collets in my Southbend headstock occasionally. They don’t release as easily as R8 does on my mill.
 
I’ve wondered about those torque specs. My ER32 collet chuck came with a fairly short hook wrench. I can’t image that it would survive 100 ftlbs.
 
Yes, they are for the ER collet nut.

The ER wrenches, are rather short for the kinds of torque they require.

As @historicalarms mentions above, the drawbar needs to be tight so the tapers lock. A sharp tap should be required to break it free. If it just falls out of the spindle, all the rotational forces are taken by the anti-rotation feature of the R8 collet. That can shear off and really mess up the inside of the spindle.
 
I think those torque specs are what they reference to achieve rated collet runout. I had the same thought when I stumbled on a similar chart - that is a lot of gronk especially considering the length of wrench typically supplied. I did some informal tests just measuring runout on an accurate endmill shank. Seemed like anything reasonably tight enough to hold the tool seemed to give me pretty consistent runout reading, within tenths at least. All of this assumes you have a good quality collet holder & collets to begin with. If its a cheapo with 0.002" runout than no amount of wrenching is going to fix that.

Seating a tool in the quill is actually a different matter. It is pulling the 2 solid surfaces together axially to seat. There is no collet action (collapsing slits). Personally I'm of the opinion tight enough to not let go is good. Hard hammering to release cant be too good for the threads on the inserted tool nor the drawbar. Even though they pretty meaty & threads are strong, doing this repeatably must take some kind of toll. If the surfaces are clean & taper in good condition, it doesn't seem to take a lot of force.

I've always been curious, when people install those power drawbar units, do they set them to some kind of torque? And what kind of spring pressure to release when its un-tightened?
 
David_R8 said:
I think more than $1800 is too much to be honest. It has a geared head but it's still a round column mill, same as mine. I paid $1300 for mine.
My DRO which looks virtually identical was $306 so the math doesn't work out. He's deducting $750 for the DRO.
Here's pics from Feb of this year.
https://www.hobby-machinist.com/threads/1-4-of-the-way-to-a-mill.82188/post-716223
Click to expand...

What about a RF30? No tooling (aside from a drill press vice), no DRO.

Just seen one... too much for me at the moment (minimal income at the moment, and I don’t have any ‘real size’ machine tooling), but it’s around the figure you posted on a RF40.


Brad
 
Bradells said:
What about a RF30? No tooling (aside from a drill press vice), no DRO.

Just seen one... too much for me at the moment (minimal income at the moment, and I don’t have any ‘real size’ machine tooling), but it’s around the figure you posted on a RF40.

Brad
Click to expand...
$2700 for a used RF-30 is crazy, crazy high. A brand new RF-30 is $2200 at KMS.
I paid $1300 for my RF-30 and that probably made some folks cringe but I live in a place where milling machines and lathes are rare.
 
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