Easiest/cheapest source of R8 socket

[Beardy MikeParticipant @beardymike]

I’ve got an R8 spindle in my mill, along with a couple of Er32 tool holders, drill chuck etc.

Sometimes it would be convenient to have a bench fixture to put tools in/out while not in the mill. Bench fixtures to do this seem to be common for iso taper holders, but more elusive in R8.

Rather than making my own from scratch it’d be much easier to start with something containing a socket already. Does anyone have any suggestions of the best source? A replacement spindle would work, or some kind of adaptor; I’m just a bit overwhelmed by how many options and nothing obvious seems to come up from a quick Google.

Thanks,

Mike

[JasonBModerator @jasonb]

This any good, cut the INT end off.

[bernard towersParticipant @bernardtowers37738]

I think Jasons found the only possibility in the world Ive just wasted 20 mins of my life looking and no search engine seems to understand the difference between internal and external!!!!

[bernard towers]

On bernard towers Said:

I think Jasons found the only possibility in the world…

A man called Ali, who sends things by Express, will sell you you a complete R8 spindle for around £70 shipped. True, it is more money than the Arc one, but it offers a solution in a different shape.

If it is something just to poke a male R8 taper into, a 3D printed item might suit.

The ISO taper ones are intended for use as tightening fixtures, for example for an ER chuck, where the nut torque (see Regofix literature) is quite considerable. This torque is adequately resisted by the notches in the ISO tool’s flange.

R8 lacks these notches and only has a relatively small pin projecting to resist any torque. In that respect, it might not be a good idea to use such a fixture on an ER40 chuck on an R8 shank.

It is not 100% clear if the Arc one has the pin so if this is necessary for the item;s purpose, it would be wise to confirm before buying.

[JasonB]

On JasonB Said:

This any good, cut the INT end off.

Probably the best use for it. I bought the INT40 version some while ago and it took a lot of fettling to make it usable. The INT40 taper was ok but a collet wouldn’t fit in the R8 taper before easing. Concentricity between the tapers wasn’t great either at between one and two thou.

Julie

[old martParticipant @oldmart]

I bought a short R8 spindle from ARC, a spare part for one of their mills. It has been running in the Tom Senior light vertical for years now married up with the splined original top half. check their machine spares, they are not very expensive.

 

https://www.arceurotrade.co.uk/Catalogue/Machine-Spares/SX2LF-Mill-Spares/SX2LF-115-Spindle

[DC31k]

On DC31k Said:

On bernard towers Said:

I think Jasons found the only possibility in the world…

A man called Ali, who sends things by Express, will sell you you a complete R8 spindle for around £70 shipped. True, it is more money than the Arc one, but it offers a solution in a different shape.

A man called Ketan will sell you a similar spare mill spindle for £45 so less than Ali. But still not the cheapest a sthat is what I linked to first

[David SeniorParticipant @davidsenior29320]

If you do decide you have to make one, it’s not too difficult. I finally got sick of struggling to tighten the ER collets when there are no flats on the chuck, and made one a couple of weeks ago.

For the key I milled a 4mm wide slot through the side and glued in a bit of 4mm gauge plate. I felt that would be stronger than just a pin.

[old martParticipant @oldmart]

I missed Jason’s link to the ARC adaptors, my excuse is that the “This” in blue and underlined in not very distinct.

[PeteParticipant @pete41194]

R8 spindles have that small pin only to prevent the R8 shank from spinning while the draw bar is partially tightened up. Once the friction becomes high enough between the male and female R8 tapers, that pin isn’t needed and the draw bar can be tightened to whatever you want. It can’t do and was never designed as anything like a drive pin at all. If your R8 tapers fit each other properly as they should, and your tool shank and draw bar threads are kept in decent condition, that pin can even be removed. Mine has and there’s no difference. If you do get unlucky and were to shear that pin under load. It’s remnants can sometimes get forced between the R8’s parallel body section and the spindle bore, seize the tool or collet shank within the spindle, or seriously burr and score a section of your spindles internal bore. None of which any mill owner is going to enjoy.

Having a short R8 taper as an off the mill tightening fixture for an ER collet chuck. You still need two wrenches and wrench flats on the collet chucks body. Simply unbelievable that some ER collet chucks are still being made without those. There not optional considering the recommended torque any of the larger series of ER collets have. So you don’t need that pin for that use either since there’s no need for any draw bar. It’s then just a holding or positioning fixture for the collet chucks R8 taper. And the opposing wrench and what ever collet nut wrench your using hold the collet chuck from any rotation, and the other tightens the nut. For the task it has to do, I’d just make one, but I’d want two larger milled flats on it for the vise jaws to grip.

[IanTParticipant @iant]

“Simply unbelievable that some ER collet chucks are still being made without those”

Given the R8/ER32 chuck that I’ve just purchased seems to be one such (e.g. no spanner flats on the body) – is there a good reason for this lack? I’m thinking of calling the (UK) supplier and returning it – as it doesn’t seem usable without them…??

 

Regards,

 

IanT

[PeteParticipant @pete41194]

There’s mills made with spindle locks or even brakes on them Ian. Even so, every well known brand name ER collet chuck I can think of that I’ve seen so far all have at least two wrench flats on the chuck body. About the only reason I can see for not having them would be just some minor cost savings by the manufacturer at the expense of the end user. All of my ER 20,25,32 & 40 series collet chucks came with those wrench flats. You might ask the company you bought your collet chuck from how anyone is supposed to properly tighten it.

If you have a secondary method of tool holding on your mill, you could also just machine your own flats into yours as there likely not hardened too much. Something like a tommy bar holes could also be used, but in my opinion are probably inadequate for enough tool holding closing torque on the collet nut unless your also using a well made pin spanner. Smaller diameter tool shanks don’t require the same recommended maximum torque values. But as an example, ER 32 sized collets have upwards of 100 ft. lbs recommended for there largest collet size. Most of us can get away with a bit less given the much less horse power our mills may have and the usual lighter depths of cut and feed rates compared to what industry might use. My own mill does have a spindle brake, but I’ve never once used it for tightening my own collet chucks since it’s not really meant for that use. The usual ER nut wrench with a standard open end wrench opens and closes the collets just fine.

[DiogenesParticipant @diogenes]

Ian, well yes I would.

– if you can’t secure the body whilst you release or tighten the closer with the chuck up the spout it’s going to be a right pain.

 

[IanT]

On IanT Said:

“Simply unbelievable that some ER collet chucks are still being made without those”

Given the R8/ER32 chuck that I’ve just purchased seems to be one such (e.g. no spanner flats on the body) – is there a good reason for this lack? I’m thinking of calling the (UK) supplier and returning it – as it doesn’t seem usable without them…??

 

Regards,

 

IanT

I have an ER25 with no spanner flats and have no problems tightening it into either of my R8 machines. Likewise no problem tightening the nut or undoing it, don’t know what Force I tighten it or my other ER chucks to but never had a cutter pull out. Never thought of sending it back.

EDIT. Just had to go and check the ER16 that mostly gets used in the CNC as I could not remember if it had flats or not as I have never made use of them, but again no flats and again no problem fitting it or changing cutters.

Should add all my cutters get changed with the holder in the machine be that R8 or MT.

[DiogenesParticipant @diogenes]

Do you have a spindle lock on the Sieg?

 

[JasonBModerator @jasonb]

Also as I have holders both with and without flats I can make my own assumptions as to why some don’t have flats and it is not due to cost cutting.

Compare a pair if ER16 holders the top one with no flats and the bottom with flats. Fairly obvious that the one with flats needs to be longer to accomodate the flats. That is why I chose the top one when I bought it for the CNC. Not only is a shorter holder going to be more rigid it also saves that bit of head room if your benchtop mill is vertically challenged. So that is two good reasons for no flats in my book.

[IanTParticipant @iant]

Thanks for the feedback everyone.

I had a cutter move many years ago and it ruined the work (it was on a Brigeport and I was under time pressure, so pushing things – always a mistake) but it’s made me somewhat paranoid to the extent I’ve always used my 2MT Clarkson (if I have the right threaded cutter) since. When I do use the ER32 chuck, I make sure it’s pretty tight – tighter than I could do by just gripping it.  I should mention that I have a problem with my thumbs (basel joint arthritus) fortunately not too bad at the moment but I have be very careful when gripping spanners etc or it can be painful for a day or two..

As I don’t have delivery of the new mill yet, I don’t know what locking arrangements it might have, if any..

Jason – are you just gripping the chuck to change tools – or is there something more to your method?

Regards,

 

IanT

 

[JasonBModerator @jasonb]

The SX2.7 has holes for a pin spanner in the end of the spindle, the KX-3 has tommy bar holes in the side of the spindle nose. Both get used when tightening the drawbar and also when changing cutters etc in the ER chucks.

When I originally got the X3 I bought one of the far eastern ER style chucks that take a similar looking collet and that just has a knurled area above the nut thread and that was just tightend by holding the knurled area with left and and C spanner with my right.

If you do have grip problems then you will need to find a way to stop the spindle turning when fitting tooling, drill chucks, saw arbors, sidelock holders and finger collets don’t have flats so you will need a way to stop the spindle rotating if the mill does not have a facility to do it. So may as well use that same spindle lock for tightening the collet nut.

[Howard LewisParticipant @howardlewis46836]

Quite often, a collet holder without flats can be tightened sufficiently by using the inertia of the machine drive to resist the tightening torque.

Having clamped, as hard as possible, give the end of the spanner one or more hard, sharp biffs with a hand or a soft mallet.  The nut will only move a very little, but apply a lot more clamping force.

Sometimes this technique has to be used to slacken a holder, with flats, that has been tightened in the usual way. The sharp impact overcomes the thread to thread stiction.

A suddenly applied force has double the effect of a gradually applied one.

Howard

[IanTParticipant @iant]

OK thanks Jason.

I can’t see from the photos what the spindle locking arrangements are on my new mill but as it will be here Friday, I will wait till then and see what I have available to stop the spindle rotating. If it’s got tommy bar holes, I suppose I could make a ‘C’ spanner for it…

But frankly, I’m still puzzled why they would make the chuck without ‘spanner’ flats.  The ‘body’ of the chuck is 1″ long, so plenty of room to do.

Regards,

IanT

[Tony Pratt 1Participant @tonypratt1]

IanT, from a practical viewpoint not having spanner flats makes the collet chuck ‘not fit for purpose’, I would return it and get one which has flats.

Blow me I’ve just looked in my milling machine tool holder selection & have also got an ER holder with no spanner flats so ‘not fit for purpose’, bought 25 years ago & never used. 🙂

Tony

[JasonBModerator @jasonb]

It is hard to expect a supplier to take something back just because a user feels it is not fit for purpose when other people have managed to use tham without a problem. The ME trade have been selling holders without flats for years, if they are all NFFP and got sent back they would have stopped importing more long ago.

 

Couple of parts I machined last week. Two identical items, machined on both sides. 4 cutters used per side so that is 16 cutter changes, two more if you include drilling and tapping the tooling plate. Fit enough for some!!

As I said the shorter distance is a bonus as far as I’m conserned and why I bought that one as it was listed with a short gauge length.

 

[NealebParticipant @nealeb]

I have both R8 and BT30 ER32 collet holders. I realised that I didn’t know if they have spanner flats or not as I have never used them – fit in respective spindles has always been enough. R8 mill – I hold the spindle pulley which is enough for collet closing; BT30 mill – has spindle nose tommy bar holes and I use those. My ER20 collets do need a spanner on the spindle but that’s a 3HP water-cooled router with the collet holder being cut into the end of the spindle. Certainly a sharp tap with a mallet to undo the collet closer nut is a help sometimes (and I always use ball-bearing closer nuts).

[JasonBModerator @jasonb]

I wonder if anyone sending their holders back to Haas as being not fit for purpose has got a refund? They are hardly likely to sell unfit goods and are not really aimed at the hobby user

ER16 & ER32.

For Ian. This is the arrangement on my two R8 machines. Relly no different to putting a spanner around the chuck flats if they had them.

KX-3, supplied bar with my added plastic handle

SX2.7 supplied spanner with a slight modification as per my MEW article. In both cases no need to go reaching upto the top of the machine and I quite often use the SX2.7 seated

lastly the chinese sort of ER chuck with just it’s knurled body

Fit enough for the purpose of making this and several more of my earlier engines

 

[Howard LewisParticipant @howardlewis46836]

You could try holding the body with a “Boa Constrictor” holder. Intended for undoing jar tops, the rubber strap is tightened by the plastic body gripping against it. (Same principle as a Stilson wrench, but no teeth to bite into the metal and cause damage)

Howard

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