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Member postings for Ketan Swali

Here is a list of all the postings Ketan Swali has made in our forums. Click on a thread name to jump to the thread.

Thread: Memorable topics discussed on this forum
26/10/2020 16:25:53
Posted by roy entwistle on 26/10/2020 15:51:42:

Whatever happened to Brian Johns. He just stopped writing.

I believe he is still around, and I think he is still using his lathe after getting some help from Hopper. He made general posts over the years on various topics, last of which was in April this year.

Ketan at ARC.

24/10/2020 19:27:42

Every now and then I like reading archive articles as published in the recent issues of Model Engineers Workshop magazine. I also like reading certain old topics on this forum.

There are always new members joining this forum, many of whom may be unaware of discussion which have taken place in the past, which could be of interest for them to read. Here are a few which are memorable to me:

Starting off in memory of the late John Stevenson who passed away on 23rd of October 2017: Todays update from Bodgers Lodge content as the name suggests.

next: Brian Johns Optimum - New Lathe arrived today his was a real beginners story over time.

John McNamaras: DIY Epoxy Frame based CNC MILL this I believe is still work in progress, and I read somewhere that he will be posting new developments soon.

So, which old threads are memorable to you? specifically those which you feel newer members will enjoy reading... ideally with content which is helpful rather than ego related anger or patronising.

For reference, I feel that this thread may be a good place to post links to such topics, if moderators and readers feel it to be appropriate, specifically for this forums ME threads.

Ketan at ARC

Edited By Ketan Swali on 24/10/2020 19:29:42

Thread: Milling for Beginners Book
22/10/2020 10:47:52

Hi MC Black,

Thank you for your comments and observations. We at ARC are glad that you are pleased with your purchase. We know from experience how difficult it is to please you, which includes the choice of delivery systems we use.

I will try to explain some of the reasoning behind what we have done.

The books are broadly generic, using products available from various sellers around the world, rather than specifically from ARC, even though many products were supplied by ARC.

Under normal circumstances, if a person purchased the books from an independent company, the 'Arc Product Guide' (APG) would not be supplied with the book.

The thin 16page (including cover) APG booklet is complementary, and only sent to customers who purchase the books directly from ARC. We just did this as an extra idea. it is not part of the book.

The long-term aim is for other companies around the world to sell the books. So for example, if AUSEE in Australia sells the books, the APG will not be supplied to them. It would be wrong for AUSEEs customers to be directed to ARCs website.

We just wanted to try out the idea of guiding the reader to a source of purchase for a product talked about in a book.

There were two Catalogue 11s included in the package, because you had ordered them...One ordered earlier in the evening and one ordered with the books. The covering letter accompanying the Catalogue 11 does say in one of the paragraphs... 'For up-to-date information on prices and/or product details, please visit our website..' So, we felt it appropriate to link the QR codes in the APG to our website. Whilst I understand and respect your views, we chose to link the QR codes in the APG to pages on our website.

I understand your concern over lack of INDEX. We debated this concern in-house, and once again, whilst I respect your views, after taking many factors into consideration (without going into detail), we felt that the CONTENTS at the beginning was sufficient.

Ketan at ARC

17/10/2020 20:57:22
Posted by Peter G. Shaw on 17/10/2020 15:46:42:

Well, I'm a little bit disappointed that these books aren't in the WSP series (Nos 50 & 51, they would have been). But having said that, I can understand that Ketan will wish to capitalize on the series since it used machines supplied by Arc.

I also note that these are quite large, at 304mm x 218mm they are quite large, larger in fact than the usual A4 size in the UK.

Peter G. Shaw

Apologies Peter. The idea of WPS was considered earlier. In terms of sales, having issue 50 and 51 in WPS would have automatically generated fast and potentially greater sales, especially to those who have the complete WPS series in their collection. But of what use would that have been to the total beginner who has yet to know what WPS is?

We wanted to see the pictures in colour, content laid out for easier understanding and reading, on high quality paper, and in hardback. The technical attributes for the books are totally different from what was possible with WPS or Crowood. These comments are made without any disrespect to those publishers or their profession.

By controlling the whole process, ARC got the products we wanted to present to prospective buyers.

Ketan at ARC

Edited By Ketan Swali on 17/10/2020 20:58:27

17/10/2020 20:12:09

Hi MCB and All,

The ISBNs are the same as the product codes stated on our website.

As Jason mentioned, they are a reworking of the two series in the MEW. They have been edited, laid out and published by ARC.

Both books are based on modern day machines. Aimed at beginners who are:

  • less inclined or able to join an engineering club for a variety of reasons, but still want to use a metalworking lathe or mill.
  • less willing or able to ask for help, but need to ask basic questions, for example: what is a headstock of a lathe, or why an end mill should be held in a collet rather than a drill chuck, or even what is an end mill.

The books mentioned in Georges posts are great. They are based on older machines where the basic principals of turning or milling are the same as those used in the modern day machines. Most of the target audience of those books had some engineering background or access to machines in metalwork at school, so there is in my opinion some presumption that the reader has some level of understanding of terminology in those books.

During the editing process, ARC has tried to further elaborate, simplify, clarify certain basic ideas for the beginner, based on questions/issues we have come across over the years.

Ketan at ARC

Thread: DHL Rip Off
13/10/2020 19:01:25

If one reads the policy paper to which Michael G has linked to, and if it is truly implemented, the OMPs like Amazon and eBay will finally and hopefully be forced to collect revenue for HMRC. If the system works, it can only be a good thing, to deal with certain overseas sellers undervalue declaration which they won’t be able to do... hopefully, to get through the postal system. Also, maybe, if the revenue is already collected for small value goods, it could mean that couriers may not need to make a customs entry for the buyer, so, maybe no handling charge?. Not sure if this will happen though. All fun and games to look forward to on the 1st of January depending on how things pan out between now and then.

Ketan at ARC

Edited By Ketan Swali on 13/10/2020 19:05:14

13/10/2020 18:44:13

Steve,

You may be right to a certain extent. Here is another possible reason for such companies to move to Prague as I mentioned on another thread a few days ago:

‘About three years ago, HMRC issued a warning to freight forwarders based in Southampton mainly, which were acting as fulfilment centers for mainland Chinese companies. The Chinese companies would collect revenue, fail to pay, and go bust, and start in a new name the next day, operating with the same freight forwarders - warehousing.. HMRC advised freight forwarders that changes in rules were on their way to hold the freight forwarder responsible for revenue which the Chinese company failed to pay. Being aware of what is coming, this kind of fulfilment business moved to certain ports in the EU, where the regulations are more relaxed.’

Ketan at ARC

Thread: SIEG SX2.7 Mill DRO
11/10/2020 08:52:46
Posted by Andy Brocklehurst on 11/10/2020 08:35:34:

I like the suggestion Ketan makes for a machine specific dro which would make fitting simpler?

Thanks

Hopefully yes. ARC is lending them one of each of the following machines: SX2.7, SX2.7L, SX3 and SX3.5ZP, which they will get in the middle of next week. They will use them to make the kits.

Once the kits are made and fitted to those machines, we will sell off those specific machines. There after ARC will direct potential buyers directly to M-DRO. At present we do not intend to sell their kits, nor do we want any re-directing commission. As they are, the kits can be perceived to be expensive for model engineers, but are reasonable according to industry use.

As ARC has no intentions to make/sell magnetic scale kits at present, our idea is to direct people to a reputable U.K. supplier who can assist. There are other good U.K. suppliers all of whom can probably assist in their own way.

Ketan at ARC.

11/10/2020 07:53:30

Hi Andy,

If you want a good magnetic scales system, Machine DRO - Allendale are the people to ask.

If you can wait for about two months, I think they will have a kit which will be machine specific.

For a 3-axis (5 micron resolution) kit from them include custom brackets, all bolts and full colour install guide, you will probably have to budget for £550.00 to £600.00 Inc.vat.

Ketan at ARC

Thread: Syil X3 CNC Spindle Failed
08/10/2020 08:30:02

Hello Rod,

Welcome to the forum.

Have you asked Amadeal or SYIL U.K. ?

Ketan at ARC

Thread: Ball bearings and friction.
06/10/2020 18:13:47
Posted by Vic on 06/10/2020 17:58:49:
Posted by Ketan Swali on 06/10/2020 16:07:33:
Posted by John Haine on 06/10/2020 16:00:12:

Rex recommends washing out with the metal shields fitted, using several changes of fluid.

That is okay provided the bearings have metal shields. However, no one really knows how old the grease/oil inside the bearing is, or the type of grease. So, difficult to say how difficult or easy it will be to remove. Worth a try I guess.

Ketan at ARC.

For several Vacuum engine designs I’ve seen they recommend either washed out plain bearings or remove the shields and wash out. Seemed to work ok for me.

Yes Vic, I agree. John Haine was responding to my comment, which I made at 15:48, to which I responded.

If you read the post I made at 15:48 first, perhaps the rest, including what John said will make sense.

Ketan at ARC.

Thread: Sieg sc3
06/10/2020 16:16:34

Mark,

Neils Clarke CL300M is a SIEG C2. Before he became editor, he changed the bearings to TRBs on his standard machine... I think about 12 years ago. Once he became editor of MEW magazine, he did his hells angel mod to 3-phase motor too. thinkingsmiley

Ketan at ARC.

Thread: Ball bearings and friction.
06/10/2020 16:07:33
Posted by John Haine on 06/10/2020 16:00:12:

Rex recommends washing out with the metal shields fitted, using several changes of fluid.

That is okay provided the bearings have metal shields. However, no one really knows how old the grease/oil inside the bearing is, or the type of grease. So, difficult to say how difficult or easy it will be to remove. Worth a try I guess.

Ketan at ARC.

06/10/2020 15:48:33
Something I have found when making prototypes is that the bearings need to be 'tight' in the sense of keeping all the moving parts coplanar. Any wobble and parasitic vibrations set in which sap the energy surprisingly quickly. I guess there is a trade-off between that and friction. I imagine people making Stirling engines must face the same sort of challenge.

Robin.

In the early days of ARC, we used to sell Stirling engines, and seek advice from Roy Darlington (key member of Stirling Engine Society who sadly passed away in late 2018). His simple advice was to remove all seals/shields and wash the ball raced bearing in paraffin. 'The oil' in paraffin was enough to lubricate the bearing, resulting in the lowest amount of friction.

Most metal shielded bearings have two metal shields. Could you live with one shield, remove the other and wash the bearing grease out?... or remove both shields, wash out the bearing, and clean the bearing when necessary.? Once metal shield/s are removed it is generally difficult to put them back on. They are usually press fitted into a grove on the inner side of the outer ring, or, in some cases, depending on the size and supplier of the bearing, the shield is retained with a snap ring... if you are lucky.

Ceramic ball raced bearings which require no lubrication are available with cage for certain sizes/without cage but with full complement of ceramic balls, where the bearing bore is 3mm and upwards, but I have no idea for how good they would be for your application.

Ketan at ARC

Edited By Ketan Swali on 06/10/2020 15:50:18

Thread: Sieg sc3
06/10/2020 12:49:52

Generally, there are four categories of buyers we come across in the hobby industry:

a. Total beginners who don't know what they are doing, but are prepared to listen and be guided. When they break things, they don't whinge. They ask what they did wrong, replace broken part, get on with it.


b. Total beginners who know think they know everything. Everything the seller says is wrong. 'I am a qualified so and so'. Everything is a warranty issue, not fit for purse purpose, 'I read this, saw that on You Tube' (70% garbage 30% good), 'I will write about this on forum, I will give you a bad Trustpilot review, I will take you to court'.


c. People who generally use small hobby machines who are prepared to tweak things to their requirements, keeping in mind the price they paid for the product. Most hobby machines (with a few Friday afternoon exceptions) regardless of which U.K. reputable dealer you buy from are fit for general engineering use. There after, it is up to the user and their ability to get the best result out of the machine, to tweak it to meet their specific accuracy/precision requirement. This category is the least likely to break parts on a machine, and if they do, they usually know why it happened.


d. Engineers who use big industrial machines in their day job. They usually break machine components/tooling because when they use a hobby machine at the end of the working day, in their garage, sometimes they are still 'in work mode'.. forget, and introduce work related feed rates to material being turned. The second something breaks, they usually say some expletives and immediately realise what they did. That evening they will place an order for a replacement part, or phone us for it the next day, and tell us what happened. smiley

Chinese built hobby lathes are light weight, and NOT anything like the accuracy or precision or assembly you may be used to with the heavy weight industrial machines which you may use in your full time job. To get the result you want, you may/will have to tweak them to meet your expectations. If you are expecting anything beyond the 'general engineering use', and if you are prepared to pay the price, look at the EMCO WABECO offering in the advert on the right hand side of this page.

The SC3 and most mini-lathes will take 8mm tooling - HSS or Carbide insert lathe tools. Depending on tool post being used - fixed or QCTP, you may need to make your own shims and use them to pack the tooling to get it to the correct height for turning, depending on tool form.

Ketan at ARC.

06/10/2020 12:49:27

Hi Mark,

This is a long post...sorry. smiley

The original headstock casting design from the East German-Russian days was made to accept Taper Roller bearings (TRBs). As U.S. demand for cheaper source of production grew, the sourcing moved to Taiwan where bearings were changed from TRBs to ball-race, and as the Taiwan production costs increased, the machine moved to Mainland China production, when the Chairman of SIEG brought it back with him from Germany where he was stationed for a while; initially for demand from a German company, followed by Harbor Freight in the U.S., and so on.

Ball raced bearings (BB), Angular Contact Bearings (ACB), Taper Roller Bearings (TRB) :

The balls in the BB have a small area of contact between the ball and the raceway/groves - Generally not designed for pre-load - but still done.
ACBs have a greater area of contact between the balls and the raceway surface.
TRBs have the greatest area of contact between the ROLLERS (not needles) and the raceway.

So, when you put on pre-load by tightening the nut/nuts (depending on who you buy the mini-lathe from), your motor/assembly needs to work harder to drive the spindle. For brushed motor machines, there are pots (can't remember the technical word) on the control board used to control torque/speed. This would have been factory set, based on the bearings used in the assembly, along with the gear/belt arrangement. So, where BBs are used, the pots are set accordingly. General advice is leave the posts on the board alone, unless you really know what you are doing. There really is no need to worry about the reduction in maximum speed.

Based on the two above factors, the RPM will drop if and when you change the bearings from BB to ACB to TRB.

The assembly is designed for hobby, rather than industrial - continuos use. Under certain scenarios, the motor could over heat, especially brushed motors where the brushes could wear faster, the drive belt could wear faster/break, if there is a hi/low gear arrangement, the gears could break under heavy load, the circuit board could also blow - based on load. So, when you change from BB to ACB to TRB, the load will increase. As long as you are aware of the factors which can effect the machine by making any changes, you can use the machine within its limitations, before something goes wrong.

You may wish to read these threads to get further ideas:
Pre-load of new bearings
SC3 Headstock bearings

In the SIEG mini-lathe range, there are brushed motors and brushless motor versions. How things work electronically with brushed motor versions is explained above.

For the SC brushless versions, there is no hi/lo to control torque. These machines are purely belt drive, and the torque is controlled via programing of a chip on the control board.

The WARCO version of the brushless motor is smaller (lower power rated), combined with a belt and hi/lo gear arrangement. Their version is discussed of the following thread:
WARCO Super mini-lathe Brushless motor version

As far as mechanical components and assembly are concerned, regardless of factories used by ARC, Chester, Amadeal, WARCO are concerned, they are broadly similar (from about four different factories). Generally, 80mm chucks are fitted as standard on mini-lathes - based on an engineers view point. There are versions available with 100mm chucks factory fitted. Initially around 19 years ago we liked that idea, but after discussion with the SIEG factory technical engineer who explained the limitations/extra load mechanically over distance of spindle, combined with load on motor/board, size on machine, I had a better understanding, learned and decided to keep with the 80mm arrangement. ARC can get 100mm chuck based spindle assemblies, along with other features, but we are happy with the situation as it stands. We do offer the backplate with 100mm chuck as optional accessories, but generally I would suggest that they are used on limited occassions.

In support of Hugh (Harry) - Amadeal, some of the bad press you read - especially ebay linked, is because on ebay, many buyers confuse the mini-lathe he sells with mini-lathes sold by 'Hu Flung Dung' sellers, because of the common name CJ-18. These buyers purchased from HFD sellers because it was cheaper than Amadeal.

So when the HFD control boards on their brushed motor mini-lathes fail, they will buy a new board from Amadeal, thinking that the board will be the same - which it might not be, or, they have failed to check the brushed motor before buying a new board. If the motor has blown, it will take out the new board!.

Amadeal sell a lot of mini-lathes directly and via ebay, and you will find happy/un-happy customers using their mini-lathe, just as much as you will find for WARCO, Chester and ARC.

What is classed as 'heavy-cut' on a mini-lathe is down to several factors: User, material being turned, feed, speed, DOC, use of coolant, tooling - HSS/carbide.

Continued...

05/10/2020 16:14:28
Posted by Mark Rea on 05/10/2020 14:10:33:

I did not see any indication of whether it was a brushless or brushed motor, and from what i have read you have to push it hard to overheat the brushed motor, which was the major problem with them.

The sieg, according to the downlaodable review does use nylon gears to drive the leadscrew.

The ebay one has a cast iron bed, the aluminium would refer to the gear/ main shaft housing. Looking at the weight of the sieg i would expect a similar construction.

As i understand their are two manufacturers, sieg and real bull, both using the same russian design.

The parts diagram of the sieg sc3 shows ball races on the main spindle shaft, as opposed to tapered roller, which are a superior bearing in terms of load bearing and alignment.

 

Hi Mark,

SIEG makes following models of mini-lathe: C2, C3, SC2, SC3.

The C2 and C3 are brushed motor versions with hi/lo gears.

The SC2/SC3 are hi- torque brushless motor versions with belt drive.

C2 is the cheapest. The SC3 the most expensive in SIEG mini-lathe range.

Most of the ones I have seen on ebay are models which are based on the C2, or sit in-between the C2 and the C3, and generally not made by SIEG. Generally, on most mini-lathes the gearbox covers are made from plastic.

Unless specifically stated, most mini-lathes are factory fitted with ball-raced bearings. If factory fitted with taper rollers bearings, or angular contact bearings (ball), then the probability of reaching 2500 RPM are reduced, unless there really is a powerful motor combined with appropriately geared/belt driven/control board torque adjusted output to deliver the RPM.

About three years ago, HMRC issued a warning to freight forwarders based in Southampton mainly, which were acting as fulfilment centers for mainland Chinese companies. The Chinese companies would collect revenue, fail to pay, and go bust, and start in a new name the next day, operating with the same freight forwarders - warehousing.. HMRC advised freight forwarders that changes in rules were on their way to hold the freight forwarder responsible for revenue which the Chinese company failed to pay. Being aware of what is coming, this kind of fulfilment business moved to certain ports in the EU, where the regulations are more relaxed.

You also state at the beginning: ' from what I have read you have to push it hard to overheat the brushed motor, which was the major problem with them. ' - Your reading and understanding in incomplete, as it all depends on your own knowledge and skills to ascertain meaning of 'pushing it hard' - this is a very loose term, especially in the hands of a beginner. Add to this, 'the base model' depending on manufacturer, combined with what the seller specified to the manufacturer as their requirement for cheap, cheap, cheap, may have failed to provide any form of 'overload protection'.... so chances of failure of control board, motor, gears breaking in these set-ups increase. There is a direct relationship between beginner and mini-lathe failure.

Unfortunately, we get calls each and every day from beginners looking for electrical components,who think they have a SIEG mini-lathe gone wrong... especially from those who have purchased from ebay. Whatever you decide, good luck with your purchase. Do consider Amadeal, WARCO and Chester in your decision making process, all of whom will also provide spares and after sales service, even if their mini-lathes are made by factories other than SIEG. smiley

Ketan at ARC.

Edited By Ketan Swali on 05/10/2020 16:19:16

Thread: Sieg Mill from ArcEurotrade
02/10/2020 15:58:44

Joel,

SX3.5ZP with R8 spindle (means without DRO), current estimate Mid-December...early January 2021 if we are lucky. Price to be decided nearer to when the goods are shipped.

Unfortunately ARC don't stock 3MT.

Ketan at ARC.

Thread: Quality Problems With the Sieg sx2.7
01/10/2020 20:21:18
Posted by blowlamp on 01/10/2020 19:33:26:
Posted by Ketan Swali on 01/10/2020 18:06:45:
Posted by blowlamp on 01/10/2020 17:00:13:

I don't understand the logic of this argument. thinking

How did Colchester, Harrison and all the other machine tool manufacturers manage to export their machines abroad without them losing precision question

Martin.

Hi Martin,

There is no logic to argue, but I really don't expect a person with your level of compitance to understand. wink

Ketan at ARC.

Edited By Ketan Swali on 01/10/2020 18:10:49

Edited By Ketan Swali on 01/10/2020 18:11:12

Hi Ketan.

Is this meant as a joke or an insult?

Martin.

Hi Martin,

How can I ever insult you? We have known each other for over 10 years now smiley

Ketan at ARC

01/10/2020 18:25:17

Nir,

You obviously know what you want, and this machine fails to meet your expectations. So perhaps you may want to call it a day. You have explored all the comments on here, and chosen what you wish to believe. Perhaps it is time for you to return the machine to the supplier and get a refund.

I really do not think you will find a solution to meet your expectations.

Ketan at ARC.

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