Arc SX2P head drop

Hi

After deciding on the pros and cons between the Arc SX2P and the Warco WM14, I've pretty much decided on the SX2P - brushless motor, belt drive and R8 are all real positives for me. I appreciate that the backlash on the Z feed is grim, but I think I can live with that. The only concern I have is, as a beginner, the possibility of a sudden drop of the head, due to the lack of decent support (ie cantilever rather than strut). I don't want to have scary events!

Can anyone give me some comfort that this isn't really a big issue? I will plan to upgrade to a strut at some point - but will that actually totally resolve the problem - if indeed there is a problem?

I really appreciate any feedback. I do a reasonable amount of woodturning and have invited several folks round to evaluate my woodturning lathe. If anyone in the Yorkshire is able to show me their experience hands-on I would really, really appreciate it.

Many thanks in anticipation.

Andrew

At the risk of stating the obvious, the standard advice is to lock all traverses, other than the one in use, (ie. Y and Z if moving the table in the X plane).

If the Head is clamped, it should not move in the vertical (Z plane).

If plunging, X and Y would be locked, to prevent any unwanted movement during cutting.

Howard

Andrew,

I believe that the answer to your question has already been covered in your earlier thread **LINK**

After watching Youtube videos or hearing about the machine, or seeing it in the flesh, some people make the comment which you make:

'I appreciate that the backlash on the Z feed is grim, but I think I can live with that'

With the greatest of respect, in my opinion this is an incorrect understanding. I would direct you to Howards comment, which deals with the observation which you and some people make. For the activity of 'milling' the Z axis has to be locked. For the activity of drilling, the Z axis is un-locked, but one does have to hold the three pronged lever to avoid the head dropping from above a certain point.

The general Z axis movement is on a rack and pinion arrangement. Yes - this movement can benefit from the use of a gas strut, but, the movement difference between it and a torsion spring is not an issue for the purpose of milling, unless one forgets to lock the Z axis into position on the relevant lever dog (can't remember how to describe it) and the dovetail - locking the gib with another lock which is standard practice when using a milling machine.

I know that you would think that as a seller I would say all of the above, but this is truly what i believe.

Arc sells the original SIEG design of machine with torsion spring. This was due to patent issues which SIEG had, which have since lapsed. Yes there are gas strut kits available and yes there are competitors who have the gas struts fitted to the machines as standard. The ones fitted to such machines are not being considered by us at present, for technical reasons, which I would prefer to keep to myself, as I wish to avoid instigating a debate or argument on the subject.

Ketan at ARC.

I have had my SX2P for a couple of years. Worked it as is for twelve months and I did get the odd tool snatch and drop. Then designed and built a double has strut assembly that fitted inside the column. Had no trouble since and a better feel while moving the head. Some pictures in my album. Still a worthwhile machine for the price and size.

Andrew

I would endorse the posts from Howard and Ketan, and whilst acknowledging that Ketan wants to make a sale, there is nothing in his post that is misleading. I have found that the issue only really occurs when the head is at the top of the column and I overcome that by keeping the head locking screw partially tightened. Once you have a feel of it, it becomes second nature and it hasn't caused me a problem. As Howard T comments a worthwhile machine for the price, with all the benefits you have already identified. Be prepared to do a bit of work on getting the X Y and Z gibs adjusted, the factory setting can be a bit variable, other than that I am completely satisfied, apart from the proverbial " a bigger machine would be nice", which is nothing to do with the SX2.

Regards

Martin

Posted by Ketan Swali on 21/01/2018 18:44:45f the above, but this is truly what i believe.

Arc sells the original SIEG design of machine with torsion spring. This was due to patent issues which SIEG had, which have since lapsed.

The mind boggles at how the use of a torsion spring to presumably support the weight of the head could ever be novel and thus patentable.

Originally, the gas strut arrangement was patented by a Taiwanese company. Only one company was prepared to take the risk of being challenged for using that design without the Taiwanese companies permission. Rest of the world - including SIEG and ARC - continued and still continue to accept the torsion spring, be it on the X2 or the SX2, and there are tens of thousands of this version in the international market.

Ketan at ARC

Ketan

I'd be quite interested to know how you can patent the use of a gas strut to support a more or less vertically moving load. On that principal every car maker in the world is infringing a Taiwanese machine tool manufacturers patent, or paying them a royalty, which I really don't believe. I suspect this comes down to commercial clout rather than patents, notwithstanding that despite the tens of thousands of torsion spring supported milling heads it really is a pretty rubbish way to do it, which is why I and just about the rest of the world do an after market gas strut mod. If the "patent rights" have lapsed, why on earth hasn't the design been changed to something rather better. I suspect I know the reason.

Kind Regards

Martin

Good question. I asked the same question around the year 2002, when ARC started purchasing the X2. There were five other competitors selling the same machine at that time in the U.K., and/or anyone who came up with an offer to SIEG, until SIEG decided to settle down with nominated distributors. SIEG was prepared to sell me the machine with the gas strut then - for any quantity I wanted, if I was prepared to take it under 'ARC branding - as a manufacturer'.. there by ARC holding the can for patent infringement for the whole machine. Only one of the five companies took on that risk, as advised earlier. In addition, my company was too small then to do own branding. Initially i was just selling the SX1 under our own brand 'Magic Mill', however, as the sales increased, issues surrounding CE compliance surfaced. So after doing necessary risk assessments, I decided to promote SIEGs brand which are backed up by technical data files for CE compliance, for the designs as they stand for SX1, X2 and so on. I was not prepared to take risks outside the designs which were registered.

For the above reasons, I don't believe that SIEG lied to me.

You suspect you know the reason why they have failed to change the design. It could be that you believe that this may be down to cost. If so, you would be mistaken. The SX2P initially cost more to make than the SX2. The fixed column was a modification I made. The long table and base carried over from the SX1 were modifications I made. For the initial quantities I committed to, these modifications cost more money than the SX2 - a standard mini-mill in mass production. The SX2P is exclusive to ARC in the U.K.. For the first two years of sale of SX2P, the product was exclusive to ARC for worldwide sales. Thereafter, this machine is still exclusive to ARC for the U.K. market.

After the patent lapsed, Axminster (SX2) and LMS (SX2 and SX2LP) incorporated the gas strut into their range. I can too into the SX2P if I want. If and when I do, it will be a little different gas strut arrangement, as I do not agree with the current factory fitted design. Until then (don't know if and when), if a person feels that the torsion spring design is poor, they can buy a slightly different machine with gas strut from our competitor, or they can put on an after market gas strut mod. Perhaps the cost saving from the difference in price could allow the buyer to make up their own mind about what gas strut mod kit they would like to install .

I understand your reasons for doing the mod. There are plenty of mods out there ranging from fixed column, gas strut, metal gears for the original X2, bearing change, etc. However, just because you made a modification, to then presume that the rest of the world who have the torsion spring design will automatically modify their machine to gas strut would be wrong. I am aware of plenty of customers who have left it alone, for one reason or another. Who am I to judge the person who wants to make the mod.

I've had a Sieg X2 (non brushless, 350W motor etc etc) for about 10 or 12 years. Yes the torsion spring thing is a little bit harry tate, I changed to a gas strut about 6 years ago. Yes the "Z" axis movement may not be as wonderful as it could be, whether fitted with a torsion spring or gas strut. However, the machine is basically a good small mill. I have become used to working around the Z axis lack of precision movement, which is only a partial problem when wanting to change the direction of feed from "down" to "up", when the user forgets that there is a issue.

Best of luck!!

cheers

Bill

Many thanks to everyone for getting back to me. I certainly didn't intend to 'knock' the SX2P. I just wanted to get the views of those who had experience of using the machine, to help me with my decision making. I recently purchased an SC3 mini lathe from Arc and I have no issues with that or the company.

I really had planned to purchase the SX2P today (together with loads of extras), but having considered all the information (from this forum and other sources), I think I would personally be a little disappointed with the head support arrangement. I have a 56 year old Meddings floor standing drill with a quill feed which performs superbly. Probably a really unfair comparison, but it's an absolute pleasure to use. So, I think I will have to reconsider and look at a machine that offers an accurate quill type facility - such as the SX2.7? I will have to revisit my workshop layout (again) and get saving (again) .

Again, many thanks for all your feedback.

P.S. If anyone in the Yorkshire area is able to recommend a mill costing < £1,400 and is up for giving me a demo, I would really appreciate it. An alternative might be to wait until the show at Doncaster - but that is way off.

There are plenty of happy users of the sx2 and sx2p with or without the gas strut mod.

You seem to be trying to justify to yourself that a better machine is needed, when in fact the sx2p is the perfect match to your sc3 mini lathe.

If you think a bigger , better, more expensive machine is needed, then why not!

What you would like and what you actually need can be two different things.

The sx3 would be my preferred starting choice but is too expensive and too big for my workshop, such is life!

Perfectly happy with my sx2p especially with my gas strut mod and digital scales on all axis.

Hey Andrew and all,

I personally didn't consider your comment to be 'knocking' the SX2P or any other mini-mills of the same family. What you read on threads and YouTube in respect of this is just a matter of opinion. Some of the comments are made by beginners, some are made by people who like to show what they have done to make an improvement. However, when a person describes the original set-up with a strong negative statement, they do so without a clear understanding of a rack and pinion arrangement. This in turn has a rolling snowball effect, if the view is not challenged.

At the end of the day, you should buy what you feel happy with. Please keep in mind that every machine will have a positive or negative feature which you like of dislike. Also there is nothing wrong with the other WM Warco mill you were considering, in this price range.

Good luck with your sourcing journey.

Ketan at ARC.

Edited By Ketan Swali on 22/01/2018 10:47:54

Thanks Ketan

All the best. Andrew

Another mod for an X2-type machine is a sash-weight, rope and a pulley or two. Unlike struts or springs it gives constant lift force and is easily tunable by adding or removing weight.

Not practical to sell though as the machine needs to be self-contained.

If you do decide to go up a size to the SX2.7 then the head on that works nicely and the built in digital quill readout will not be affected by any backlash.

Hi All

Just to let you know that upon checking my workshop, I don't have enough space for an SX2.7.

So, I have bitten the bullet and ordered an SX2P from Arc.

Many thanks for all the help and advice.

Cheers. Andrew

I have the Chester version of the SX2 mill. It has the damper type counter balance. It also has a mechanical stop block that I can slide up and down the vertical ways. Never had a problem with head drop.

When I set up a job I find the relevant position for the head and then adjust the stop under the head. It is then not possible for the head itself to drop at all. Also I tighten the lock on the head. All movement is then done buy the micro feed on the quill.

regards.

One other slight mod I made while fitting the gas strut assembly to my SX2P was to pack out the rack. This by trial and error reduced the backlash by getting the correct dimension between the rack mount face and gear centre.

I have an early SX2P, still with the coil spring. The underlying problem is the backlash in the rack and pinion. That is the same regardless of spring, gas strut, or sash weight. The only operation where I have not figured out how to prevent head drop is breaking through when drilling. Nothing bad happens, just a conspicuous 'clunk'.

If adjusting down using the fine feed to get to a vertical dimension, I keep sufficient friction on the Z-axis lock to ensure the head remains biased up, It seems to work, If I do supect the head has dropped doing this, time for the Rizla Blue..