pulleys for x1 mill

Is anyone willing to make/sell/point me in the right direction for some of these? The plastic gears are utterly rubbish and I cant afford a new mill? Thanks for reading!

fizzy,

Have a look at this recent thread.

I believe that Neil was very satisfied with his PolyVee conversion of an X2.

... presumably an X1 conversion would be similar, but smaller.

MichaelG.

fizzy,

The plastic gears are a fail safe. If you overload or try to use the mill beyond its limitations, the plastic gears are designed to break, reducing the chance of damage to the motor or electrics.

Ketan at ARC.

fizzy,

Also read this thread by Graham Meek::

http://www.model-engineer.co.uk/forums/postings.asp?th=75567

Ketan at ARC.

Surely, if that was the intention, the gears would be made stronger and the drive key would be designed to break. With electronic speed control the overload protection should be built into the electronics.

Russell.

A belt system is better IMO since it produces belt slip when under too much loading and nothing gets damaged

Agreed Russell,

But this is a small light duty machine - not an industrial workhorse. There is overload protection in the electronics. However, depending on what the nature of overload is, at that split second, it is a toss up between what will go first, the gear, or the overload kicking in. The machine is not capable of reading the users mind!.

Almost every time ARC has received a request for a replacement gear, it has been due to the users inability to understand the machines limitations, or the user forgeting about the limitation. The experienced users understand this. New users sometimes dont.

Ketan at ARC.

Ady,

If you read Grahams post to which I referred to earlier, you will note that he got a second hand machine (not from ARC), where the previous owner had the idea of making metal gears thus making it noisy. The plastic gears overcome this, and the belt drive will probably make it even more quieter, and possibly better, if done correctly.

The X1 family have thin section ball bearings in the spindle. In the ten years of ARC selling the SX1/SX1L, I have come across two people who have done belt conversions. In both cases, the thin section bearing located at the top of the spindle got damaged due to the lateral load/force introduced on the spindle. In both cases, they blamed the 'cheap Chinese bearings' rather then thinking that the lateral load/force on the spindle introduced by the belt drive conversion may have something to do with it. Having said this, there are designs out there - home made and possibly commercial for belt drive conversions, which may or may not work. Some commercial kits profess to have 'better' bearings, which is marketing BS!. The bearings are correctly specified for the use this machine is intended for. Any other suggestion is a total load of b******s.

I guess Graham might do a conversion. Being aware of his work, I would guess that his attempt might be better then some of the conversions I have come across.

Ketan at ARC.

Fizzy, I converted my X1 to belt drive using David Whites article in MEW 147 Feb 2009. It uses

Peatol pullies and a Gates belt from Beeline. Its worked fine for 3 years.

Best of luck Pete

Ketan,

Interesting point about the loading on the bearings of a machine modified for belt drive. I modified my mill about 5 or 6 years ago and replaced the useless plastic gears with a toothed belt drive. Since the toothed belt does not stretch (in theory!) then I would expect the loading on the bearings to be much the same is it is for gears, because there is no need to tension the belt to maintain a (relatively) non-slip drive.

It has been noticeable in the various threads on modifying these mills that the trend has been to poly-v belts or similar, and to reject the toothed belt drive. I guess mine cost me about 20 pounds for the pulleys and belt, and it fits in the same space as the original gear drive with approximately the same ratios. It took me about two hours to modify, and has been working happily on the same belt for about the last five years. Of course, I have lost the alleged 'safety factor' of belt slip or tooth breakage (!!!) to protect the machine in case of jamming, but despite stalling the machine several times (no-one is perfect), I have had no other damage (but see below)

Incidentally, I don't entirely subscribe to the catastrophic failure mode of the gears providing protection on jamming. The gear on my machine cracked radially, but apparently not due to a jam - it seemed to me that the gear was somewhat loose on the shaft, and the key was a poor fit, which I believe caused a shock effect when loaded, until eventually the gear cracked radially through the key slot. There is a suggestion in this thread that the electronics should protect the machine, but this was definitely not the case with the older machines. If the machine was jammed, the output driver of the electronics simply went short-circuit, and yiou lost all speed control - it happened to me several times, until I became sick of repairing the thing, and built my own fold-back current limiting circuit.

That's a great philosophy if the gears are reasonably easy to get to for replacement. I don't know the X1 but on my small mill (WM14/16 lookalike) I've never been able to figure out how to actually get at them.

My thoughts on some ot the points mentioned on this topic.

I am sure plastic gears would be quieter than metal ones, 'under the same conditions' however in the case of the machine I had (a secondhand CMD10) the gears are in general, poorly located on a sheet metal box. The gears have quite coarse teeth too allow for the imprecise meshing. Putting metal gears on the same supporting structure is definately going to be noisy!

I really cannot see how the radial loading from a belt drive can load the bearings any more than the cutting forces. As it happens I converted mine to polyvee and used a different motor and I regularly used 10mm end mills on steel without any problems. To be fair there was no radial belt load on the spindle because I modified it by extending the keyway and fitting a pulley with its own bearings effectively creating a quill arrangement. At the same time I replaced the ballraces were ones that I was told were better than the originals. (got very slightly warm at 4000rpm though)

As Ketan says, the X1 is a light duty machine but is a good starting point and it has lots of scope for improvement. With care it will produce quite accurate work. The main reason for me changing machines is because of the small table travel, which the X1L solves.

Ian

also, when the motor gets very hot, which it does after prolonged use, the gear on it goes soggy ant the key tears through it. I have to praise machine mart for their parts service and cost of new gears, they are pennies each, usually in stock and posted straight out. I try to keep 3 of each in stock. Alas the electronics are utter rubbish and readily fail! Only on the machine mart model I am led to beleive?

Hi All

I have one of these little mills, did break a motor gear so now have three spares with my luck it will be the other gear that breaks

I have a question for wotsit in regards to how he fixed the electrics, mine has a mind of it's own, (works fine then loads of switching on and off ) have bought a new switch (one that increases the speed) and the two IC's that bolt on to heat sinks but a bit weary so will wait until it gives up the ghost..

Going to post a photo of what has saved me a load of hand cranking

Hi All,

I have done a belt drive conversion on my X1 mill. I made the pulleys from a cast aluminium blank but it coulld easily be made from stack of discs cut from aluminium plate pinned together and then machined.

I have not had any problems with the spindle bearings. In fact when I designed the belt drive I was much more worried by the lateral load on the very small motor bearings rather than the much larger spindle bearings. For this reason I used a timing belt drive from the motor to a layshaft and then a vee belt drive to the the spindle. For further information see:

**LINK**

Mike

I have just added some picture of my conversion in an 'X1 Mill' album

I dont know what electronics are inside the machine mart model. ARC has sold plenty of the SX1/L over many years. Failure rate has been low. Based on conversations had with buyers who buy replacement gears from ARC, breakage has usually been when using a two tipped indexable carbide end mill - due to intermittent cut with incorrect feed/speed/depth, or when using a fly cutter at incorrect feed/speed/depth, depending on the material being milled.

Again, this is a light duty machine, designed for intermittent and not prolonged continuous industrial type use. It is a hobby machine, built for the hobby market at a price dictated by mass affordability, rather then rugged precision continuous/industrial use, which in turn would be more costly which in turn would suit a more limited affordability market.

First you suggest that the gears are rubbish and then you suggest that the electronics are rubbish. Perhaps you need to pay the price and consider a bigger machine more suited to your needs, rather then slagging off a machine which is not designed for the purpose of YOUR intended use! .

At the end of the day, you definitely get what you pay for. ARC has been extremely happy with the sales of SX1/L over the many years we have been selling them. What customers wish to do with them in terms of adding belt drive is entirely up to them. At the end of the day it starts off as an economical light duty machine. This is a hobby, and the conversions I have come across are good, bad and ugly.

Ketan at ARC.

The plastic gear in my X1 failed because the key was 3mm long with nasty burs on the edges. It took a while to find the problem because at first glance the gear looked fine and because the plastic had melted around the much too short key, turning the gear by hand did turn the motor. When i did eventualy did find the cause of the problem it was easy to fix with a new piece of key steel of the right length and a new gear. The mill was about 8-9 years old before i had the problem, and is now only used for small drilling jobs as i now have a bigger mill.

Cheers Derek

there is the possibility that it depend where the gears are sourced from, I have a similarthing happening here, a friend has two 5.5hp horizontal shaft 4stroke motors, they look identical. One is a Honda, and the other is a clone, both made in China, the plastic govenor and gear collapsed on the clone, so we took the gear etc from the Honda (not working, other problems), and put them in the clone, bingo up and going. On inspection the damaged plastic was rubbish, fine for making plastic toys, but not engineering grade. Ian S C

Hi Grey,

In the 9+ years ARC has been selling this machine, these gears have not deformed on the teeth due to running hot. This is not a problem we have come across. Poor alignment is something which does happen, but not something that has majorly effected this family of machines. Breakage resulting from this type of a problem is very low.

Issue has been more due to perception due to lack of knowledge, rather than quality of plastic component.

There were many good and bad modifications made to this mill by David White - in my opinion. His series resulted in good sales for us and others for this mill, but in some cases, for the wrong reasons. In short, in my opinion, some of Davids modifications were done to turn this machine into a heavier duty something for which it was not designed for.

By the way, ARC has purchased David Whites machine which was used for the articles. One day, when we get around to it, we will see what are the real effects of his modifications.

Ketan at ARC.

Edited By Ketan Swali on 10/11/2012 10:35:30