Does Anyone Know A Good Machine Shop?

[ianyonok]

Does anyone know a good machine shop in the north. I'm looking for a truck/car repair workshop that employs machinists who know how to use machines and measuring tools.
I have a 45 year old crankshaft from a Triumph twin that needs to have the big end journals ground. This requires a large machine specially for the job and a machinist who knows how to use it.
I did find a shop in Chiang Rai that had a crank grinding machine but there was no-one there who could use it.
I have heard that machinists here can earn very good salaries, so they must be in short supply.
Grinding crank journals is a skilled and precise job. You need at least a vernier micrometer to measure up to 0.0001".
Small bike repair shops and small corner machine shops do not use precise measuring tools but do the machining by "feel and fit".

Here is a pic of a crank grinding machine.... for those who don't know what they look like (I had not seen one before). But sadly, this one is just collecting dust...

 

[John Aero]

While I have had some good stainless steel fabrication done in Chiang Mai (the guy did get confused between metric and Imperial dimension’s though) and a mate has had Ok parts made for his Zundap’s and DKW here I would not want crank grinding done locally. Aside from being a different level of technology if they make an error on a 45 year old crank you will have serious issues. I would bite the bullet and have it done in the “West” - with such an old item would select a specialist old Brit bike shop – Oz, USA, Europe.

 

[canthai]

Years back I tried to find a shop - in BKK even - to grind my HD crank. Sad to say - no luck. Put it down to my non existent Thai language skill maybe.
Took back to Canada, had it done, into the suitcase, off the bird. Along with all the bearings, seals, case cement, ... Would like to find one here.

 

[ianyonok]

I could take the crank to Europe or the States, but really wanted to find somewhere in north Thailand. With the number of vehicles on the roads here, there are many places that do crank grinding. I know of a place in Udon where the machinist knows his stuff and earns 40k Baht a month. There is also a shop in Ubon that I saw on Youtube. Savannakhet in Laos has a machine shop where they do crank grinding. There must be many places in BKK too. I was just looking for a shop in the north.
On a recommendation from Joe, at Joe's Bike Team, I went to Chiang Mai Yontrakit. It is just off the SE corner of the moat right in the city, at; N 18.78120 deg, E 098.99427 deg.
Quite a big shop with 2 crank grinding machines that look like they are used almost daily.
I discussed the job with 2 of the machinsts (my Thai is OK). The senior machinist had a vernier micrometer and knows how to use it. I had the specs in metric and imperial. Shops here are more used to metric.
The crank was already on the 2nd grind size. Triumph list 3 oversize shell sizes, incrementing by 0.0010".
So, I could only go to the 3rd grind size. However, I did later find a vendor selling -0.040" shells, so we could have gone another 10 thou but best avoided if possible.
I picked the crank up the next day and have brought it home. The journals have been polished with something like 400 grit emery. I'll polish them more before building the engine. Now bought a 2nd hand 1-2" vernier micrometer on ebay, so that should be here in a week or so and I can try to properly measure the journals. The spec is +/- 0.00025" so can't measure properly with a regular mic.

A good sign when I arrived, plenty of engine parts hanging around the entrance to a large machine shop full of machines and quite a few staff in uniform company T shirts.

The machinist who ground my crank on this machine.

The second crank grinding machine. Both machines in use when I arrived.

1971 Triumph T100C crankshaft..... The 2 journals before (ugly).. history unknown.

....and the crank after big ends re-ground...The main bearing journals should clean up OK.

Joe had a 2nd suggestion and I found Jagkhon Diesel. A very interesting place. Actually, they didn't do crank grinding but specialised in making gears. They also had many other machines, including the long bed lathe on the right here.

They can make any kind of gear in steel, plastic, bakelite, whatever.

Interesting pieces; thread cutting, spline cutting and gear cutting done here.

Heavy worm drive gears.

If required, when machined, the gears are sent to BKK for heat treatment.

A gear hobbing machine. A very interesting process (perhaps I'm weird..)

Jakgkon Diesel is just NE of the moat on the 118 at; N 18.79930 deg, 099.01505 deg.

 

[canthai]

Super. Will drop by both places and note locations.
No more overweight suitcases for me !
Thanks

 

[ianyonok]

A couple of other shops in Chiang Mai that I found;

Wiwat Steel on Bamrungrat Rd, east of the city; N 18.78993 deg, E 098-00883 deg.
They have steels and no-ferrous metals up to large sizes in round, hex & square bar. Also large pieces of cast alumininum and hollow phosphour bronze bar for bushings.
One of the best metal stockists I have found.

They also have a 4 mill Baht CNC Waterjet cutting machine. Operating at 60,000psi, it can cut thick plate metal. The machine came from China but the waterjet head and operating system came from USA.
I had a wheel embellisher for my cafe racer cut out there, from a plate of 5mm thick alumium alloy. The waterjet cutter leaves a pretty good surface which is easy enough to polish up.

Another place does laser cutting of steel plate. I could get BSA M20/M33 clutch plates made there.
A little out of the south side of the city at; N 18.73513 deg, E 098.96563 deg.

 

[DavidFL]

Fantastic. It sounds like your trip down was well worthwhile and you won the lottery for machine shops & info.
A plug for Joe as he certainly knows his stuff being an old hand here. If anyone needs some fabricating or engineering work done Joe is your man. If he jcan't do it .he will know where the best place is to get it done.. Cheers Joe @ Joe's Bike Team.. Joe also rents bikes and they are always in top condition .

 

[canthai]

Gmaps took me here - is this correct ?
Google Maps

The first place on Bamrungrat Rd did not come up at all.
I can find the Road no problem but the coords - no go

 

[canthai]

Google Maps

 

[John Aero]

Still think you took a risk – my experience of working as a technical manager in Asia in the 80’s showed me that developing countries can leapfrog technology i.e. have little expertise in something fairly common in the “West”. Your 1-2” micrometre is almost certainly out of calibration – have you come across Plastigauge a fairly good method of checking plain bearing clearances Plastigauge - The Accurate Way to Measure Bearing Clearances...

 

[Big_Dave]

Great post Ian.

I started life as a Fitter Machinist and just love the stuff. I have a small lathe in my workshop now that I turn stuff up with when reqd. Its like riding a bicycle, you never forget how to use them.

I always stick my head in machine shops when I come across them. I've found a lot of the fishing port areas tend to have a shop or two.....brings back a lot of memories seeing guys at their machines.

 

[ianyonok]

Canthai,
Not sure why Google is off there. I can't seem to get a google maps link on my phone.
But here is a couple of pics that should help.

I am going back to the shop today, to pick up a barrel from a '52 BSA, after sleeving, honing and boring.

 

[canthai]

Thanks, Muchly appreciated

 

[ianyonok]

John,
Thanks for the input and I agree with what you say. But I wanted to do this work in my home country, which is here. Messing with old bikes and engines is a hobby and interesting learning experience for me.

I received the VIS 1-2" vernier micrometer, bought on Ebay. It has a friction thimble and came with a 1" standard and C spanner. After zero-ing it, used a 50mm standard from another mic set to check it near full scale. It seems to read 0.0002" low, at that. Best I can do for calibration.

After watching lots of Youtube vids, did some measuring on the freshly ground journals of the T100 crank. Took 8 measurements on each journal to check for ovality, taper & size.
Results; max taper 0.0005" each journal and ovality 0.0008" & 0.0006".
The journals measure between -0.0007" and +0.0002" relative to the minimum on spec size of +/-0.0005", for the conrod on this 3rd grind.
If I add in the micrometer error of -0.0002", the size looks a little better, but still undersize. The worst case looks like 1/2 thou undersize.
Another factor was the poor condition of the rusted journals prior to grinding. They still have some imperfections, so the machinist would have been trying to get the finish as good as possible, too. I have now polished them with 600 & 1200 paper.
So, I think it is good enough to use.
Yes, I have seen Plastigauge and it looks like a good double check. Very handy in car engines for checking multiple main bearing clearances, too. But the old Triumph big end bolts are torqued up until they stretch a certain amount and not recommended for re-use.

 

[ianyonok]

Oh, I just found the big end clearance spec which is 0.0005" - 0.002". That indicates the crank journals should be fine.... I think.....

 

[ianyonok]

The story continues....

I went back to the same shop in CNX with a BSA 500cc single barrel (with a new Gandini piston), to have a new liner machined and fitted, then boring and honing.
When I got back to the shop, the next day, the machinist was trying to check the piston to bore clearance with a set of feeler gauges.
I only had a set of feelers with me too, but could tell the clearance was insufficent. I got them to hone some more out. Feelers are not a great way to check bore clearance. I guessed it may be OK and took the barrel home. Really, this shop does boring and honing like other shops. They dont have the correct tools to measure accurately enough so, do they boring and honing by "feel".
After I got home, I could see that the clearance is between 0.0035" and 0.0040". The BSA spec is 0.0045" - 0.0065". That is a very sloppy fit by today's standards.
So, now, I have bought some more 2nd hand measuring tools on ebay; a Starrett 3-4" mic for 20 gbp and a Mitutoyo bore gauge for 40 gbp. Also bought new standards of 1", 2", 3" & 4" which I can use to zero and calibrate all the measuring instruments. A bore gauge is really the best way to check a bore diameter, relative to a known spec.
I could remove about 1/2 thou by honing at home, but any more and the bore may start to get out of shape. I need to take out about 1 thou. So, expect to be taking the barrel to a shop again, for more honing on a machine, but this time I will have to take mic and bore gauge with me.

 

[John Aero]

Ian hope you did not think I was being too negative or cautious but did not want you to have a fairly rare item ruined – you obviously have the drive and ability to follow through on this, good luck and enjoy! Yes the old engines had big clearance’s this plus being low revving make them a bit more forgiving than modern ones.

 

[John Aero]

As I said Asia can leapfrog technology – in the 80’s in Singapore coordinate measuring machines became common (almost always operated by women – in the West a totally male preserve) but they could not use basic methods - height gauge, sine bars, slips/Jo blocks etc – did they need to, probably not!

 

[canthai]

My Father was a machinist. Many hours with him working the lathe. Using Micrometers, bore gauges, etc
Miss him every day ...

 

[ianyonok]

John,
Your reply to my post was excellent, Thank you, gave food for thought.
Actually, a T100 crank is not so rare, you can pick them up on Ebay. There are still lots of old used Triumph spares around, fortunately, particularly in the USA.