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Discussion Starter #221
Moving my shop

I’m in the process of moving my machine shop. The last load of equipment nearly blew my truck tranny, pictures to follow. Everything in the new shop must be 115vac house hold power. I purchased a Cherry Picker hoist to unload equipment. Although rather clumsy to position, it works OK for garage lifting.
The new lathe is a little light weight but will work with lighter loads. I purchased a set of ½” carbide turning tools on EBay, the inserts are JUNK. I’ll fire up the lathe in a few days to try out a quality set of inserts. The work load is far behind on account of the move. Hopefully I’ll start to catch up in the weeks to follow.

JT
:Cheers:
 

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Hi guys, I am back doing the re-bores and projects to enhance the cylinder business, the workshop almost done just spent the last week doing the 3phase supply for the smaller machines that I run on a converter.
The machinery has been moved around and about and I think I am finally there(unless I buy another machine) still looking for a 14" shaper for my hobby if anyone has one in the UK.

I have just done my first rebore and hone today after a long absence.
The barrel is a mates Yamaha FSiE, it was the original barrel that he took off and put a new copy barrel on that did not work well, think it had too much mid range causing it to rev out too soon. Looking at the ports both barrels had different port heights and I think the newer exhaust port was too high. I will compare the ports later and make some notes.

The barrel was cleaned off and old gaskets removed from the base.



I found the best collars/adopters to match the barrel so no damaged would occur whilst clamping.


The reboring machine in action.
The new piston was 0.50mm over size and measured 40.46mm at the skirt so the boring machine was set to piston size, (I wanted 40.46 and it came out on size wow not bad for long time not in use)


Honing for bore to final size and cross hatch finish. The one thing we dont get over here is piston clearance on the new piston box, because it is only a small piston it needs very little clearance so I honed it to the feel of the piston until it just had a nice sliding action.


Job done, rebored, honed, ports dressed and final clean.


I am hoping now to continue with the liner work and make some patterns for sand casting.
I do have a machine to repair and some tooling to make but finally hope to make some progress.

Lathemad Kev.
 

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Discussion Starter #223
Kevan; thank you for your input & efforts. I’ve been buried in my shop move for the last 2 months, more on that later.
I’ve seen your kind of cylinder mounting set ups on some of the Chinese boring machines featured in the Alibaba web sites. (I’d expect that space is a large consideration in some of your equipment decisions)
What is the brand & size limits on your cylinder boring machine? I’m sure that some of these machines will show up on our side of the pond. Will you please show how the tool bits are set to size? I’ve been hyping the Kwik Way brand for so long that the Rottler & Van Norman brands have been buried in the past. The other 2 brands are equally robust & do well on cycle & other small engines. I hope in the future that you might consider my kinds of cylinder boring stands. Sliding around the multi cylinder units will soon give you some problems.

Longer stands will help with the larger cylinders

I watch Craig’s List from time to time looking for cycle shops going out of business. Most times many cylinder boring machines & equipment will go at excellent prices. I also hope that many other readers would get into the small business mood & consider our writings a little more seriously. ($$$) With some time & a savings budget, anybody can muster up 2 thousand $ & start to make money servicing small engine cylinders.

How about your honing machine; what brand? Is tooling readily available? Is there an adaptor to fit Sunnen tooling? It took me some time to save up & locate a set of small mandrels to operate my hone from 1 ½” to 2 1/2”. With my Sunnen equipment the AN adaptor will run all of the larger size bores from 2 ½” up.


Larger tooling to fit our Sunnen machine.

You mentioned your 3 phase converter; I’ve converted my equipment to household power. I can only run 1 machine at a time because of my 15amp breakers.
 

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Hi JT, hope you are well and getting your home workshop sorted. I have just about got mine done will post some pics soon.

The red boring machine and table was made by SPS in England(38mm to 95mm bores) and is like the Van Normans, here is a pic of the tool mic for setting the cutter size. I am trying to set this smaller machine up on the boring table but found the barrels did not sit square to the table, I think the problem was that I fitted a foam filler to the underside of the table when I made it and it lifted the table when clamping barrels down.


My honing machine is a Delapena that I think uses the same mandrels as your Sunnen machines but we do not have a very good supply of mandrels like you have, we are a bit limited to whats available.


Lathemed Kev.
 

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Montessa 250
last week I was ask to do a rebore and hone on a 250 aircooled barrel, my customer was doing the rebuild and he dropped of the barrel and a new old stock piston that he had been given, when I checked the sizes the piston was only 0.15mm bigger then the bore and only 0.05mm bigger then the worn part of the bore in the middle.
A rebore would not be possible due to the lack of metal that needed to be removed, so I had to hone out the bore to the piston size plus piston to bore clearance and true up the bore plus keep it true.

calipers are used to measure the piston and for setting the bore gauge to piston size.


now the caliper is set and locked off the bore gauge is set to sizeL


the bore gauge is set to zero (a little tricky to get set correct in the caliper) now we can use the bore gauge in the bore to check size and true the bore



at the honing machine the bore starts to come true by honing the barrel at the outer ends of the barrel with regular checks with the bore gauge until the bore is true and straight, after the bore is true we finish honing the bore to get the piston clearance we require, the barrel is rotated on the honing mandrel to keep the bore true


lathemad Kev.
 

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DT400 Liner.

I have been busy making the new liner for the DT400. the machine work is a straight forward process but the port alignment work is proving difficult, JT makes it look easy but until you have done one you find out that the ports angles are hard to judge were the cutter will end up on the inside of the bore.
I think it is even more difficult when fitting a very thick liner because the angles become longer when cut in at 45geg and you end up getting to close to the next port.
I have cut in the 4 smaller ports at 45deg inwards at the moment and I will refit the liner to study some more, this is were it is a good plan to make a port map in advance



I will keep you posted.

LathemadKev.
 

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Discussion Starter #229
Kev; I eyeball the port angles. The front transfer port is always the first one to cut After you do a few it starts to get easier.
JT
 

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DT liner
Thanks John, I was planning a phone call, I have spent today getting a bit more done and almost gave up the other day due to having problems with solving the angles but I have sent too many years doing rebores and buying equipment, plus I like doing the work and I have my eye on two more boring machines.

I was trying to eyeball the angles but then you are right the ports need to be study very carefully before cutting but I was over shooting the angle on the front transfer.
I have now re-cut the ports bigger and it helped to slowly increase the port size to watch how it came out on the inside, I guess you learn by your mistakes and you get better with practise.



I was not looking forward to cutting out the bottom of the liner but once I rechecked my sizes it came out ok and easier than I thought it would be.



The new liner is back in now and I am just checking the alignment and dressing up the lower portion on the liner.
I hope to give you a call when I work the time zone difference.

In my town we have a local auto engineering firm that does engine machining work like re-bore, head skimming valve seats and more and I have just been told it has now closed it doors after been in business since 1918, I guess it is the sign of the times

Lathemad Kev.
 

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Boring machines and workshop update

I have recently added two more boring machines to my collection, both are made by SPS and one is a mark 8 the same one that I have and the other is a mark 10, same size has Van Norman 944 I think.The mark 10 is a rare machine and I have only ever seen one for sale before that costs double what I paid and that was about 5 years ago.

I now have the boring machines set up in the middle of the workshop and have just about got things in the right place after a few more changes to get things right.

The DT400 liner is on going and I have just been doing some more machining to the transfer ports today after finding out the barrel is a YZ400 and I have got the new port dimensions, the tricky bit is working out the port angles so the gases flow towards the inlet port and not facing the exhaust port.





lathemad Kev.
 

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DT400 liner

Hi to all,
update on my dt400 liner work.
the customer has got the barrel back complete with new liner and piston ready to install and ride,
after a few goes I found out the hard way what works best for me when machining the ports, the transfer ports are quite tricky in getting the angles right so that the widows point towards the inlet and away from the exhaust port, also found that the transfer port roofs need to be angled upwards to help the fuel charge go above the piston.









I am now working on a set of RD350 YPVS barrels that I have got spare to practice doing both water cooled barrels and those fitted with an exhaust power valve.

Hoping to keep you up to date with the progress.

Regards Lathemad Kevin.
 
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