Thread: Your latest project

Originally Posted by Gavin Newman

Cooper, good stuff but before you go driving it you really need to rig up a chain guard to protect your elbow. Any kart shop will have one you can modify to fit.

Thanks Gavin, iv got a chain guard in the shed, going to put it on today and fix the motor mount to

Originally Posted by xXvapourXx

Thanks Gavin, iv got a chain guard in the shed, going to put it on today and fix the motor mount to

Goodoh - I've had a chain snap on my kart at over 160 kph at Phillip Island - not pretty......

My latest project is a natural gas powered forge.
The WIP is here.

Well gents I am impressed last time I stuck my head round the corner in this thread was way back when Azrock was doing his panel van

I hope to be able to contribute soon although it will be smaller items I am sure.

Originally Posted by mahgnia

The lathe's minimum speed is 125 rpm, maximum is 2000 rpm.
It would be handy to be able to get it down to around 60 - 80 rpm, especially for thread cutting and large diameter workpieces.
I've been thinking about making an intermediate pulley pair on an idler shaft, mounted under the existing driven pulley as shown in the attached photo. These pulleys would be sized the give half the indicated rpm.

The other day I found a particularly unexpected feature of the C6 lathe - the low speed intermediate drive pulley cluster has no ball bearings, but the cast iron pulley runs directly on a steel (mild) shaft.
I found this because the pulley had a minor seizure on the shaft due to me not noticing the oiling point on the end of the shaft, right at the back of the drive housing.....

At this point I decided to fit ball bearings and a spindle to this pulley cluster to avoid this happening again.

The original shaft assembly
DSCN8694.jpg
The new/modified parts
DSCN8699.jpgDSCN8698.jpgDSCN8697.jpgDSCN8696.jpgDSCN8695.jpg
Back in action
DSCN8700.jpg

All the machining had to be done on the lathe running on the high speed drive settings, so there were lots of cast iron, steel and aluminium chips spraying all over the workshop!
The toothed drive belt was slightly damaged when the drive seized, so it will eventually need to be replaced.

While in there I worked out how to fit an extra low speed intermediate cluster as per the quote above.

Pictures here
DSCN8706.jpgDSCN8705.jpgDSCN8704.jpgDSCN8703.jpgDSCN8702.jpgDSCN8701.jpgDSCN8707.jpg

I calculate that this should give me two extra low speeds of 62 RPM and 85 RPM at the spindle.
With other combinations of low to extra low, or high to extra low pulleys, there may be other useful speeds available.
I will need to get some other v-belt sizes to complete this drive properly, but it seems to test OK with incorrect length belts (unable to tension them properly for use under load on the lathe)

Andrew

Really nice job, that 60 odd rpm will be great for threading.

Dave

Nice work Andrew, and not a big job getting to the change gears either.
Well done

Phil

Since building my version of John Stevenson's swinging thread cutting tool ( John comes up with some great ideas) I have run into the problem of my live centre not having enough clearance to allow for cutting small threads. I looked at buying an extended nose live centre but they required using morse taper reducers to to fit into my MT3 tailstock, too much overhang and expense. So I decided to modify one of my existing live centres, being made of hardened steel this required some heavy cutting with a carbide insert. I mounted the live centre in the headstock in a MT3/MT5 adaptor, fitted the faceplate and made up a top hat shaped clamp that bolted firmly around the live centres shaft and bolted to the faceplate, I checked runout with a dial indicator to ensure it was true, then let the sparks fly removing the hardened outer layer. After that it was relativley easy to machine it down to size. I can now cut 6mm diameter threads.
As a test for the whole set up I picked a pair of Engineers clamps as a project to make and decided to up the challenge by making the threads for the clamps out of 10mm diameter 316 Stainless Steel bar. The combination all worked well.
Bob

Thanks Phil and Dave.

It was a priority to allow enough space for the lead screw drive gears so i could use the extra low speeds for thread cutting.
This was the main reason that slightly shorter v-belts are required.
The extra-low speed big pulley was made removable to accomodate this, and also to allow fitting of the short final drive belt without too much difficulty, otherwise the point of the extra low speeds is lost.
I also had an old nyloc 5" pulley i could use for this(probably the main reason)

Andrew

Hi Andrew,
I just went back and had another look at the pictures and after reading what you wrote above, you have put a lot of thinking and planning into this conversion (not to mention work) and it's great to hear it works well.
I like the way you have bolted the pulleys together, look very neat and factory looking.

Dave

Originally Posted by krisfarm

Since building my version of John Stevenson's swinging thread cutting tool ( John comes up with some great ideas) I have run into the problem of my live centre not having enough clearance to allow for cutting small threads. I looked at buying an extended nose live centre but they required using morse taper reducers to to fit into my MT3 tailstock, too much overhang and expense. So I decided to modify one of my existing live centres, being made of hardened steel this required some heavy cutting with a carbide insert. I mounted the live centre in the headstock in a MT3/MT5 adaptor, fitted the faceplate and made up a top hat shaped clamp that bolted firmly around the live centres shaft and bolted to the faceplate, I checked runout with a dial indicator to ensure it was true, then let the sparks fly removing the hardened outer layer. After that it was relativley easy to machine it down to size. I can now cut 6mm diameter threads.
As a test for the whole set up I picked a pair of Engineers clamps as a project to make and decided to up the challenge by making the threads for the clamps out of 10mm diameter 316 Stainless Steel bar. The combination all worked well.
Bob

Hi Bob,
I see you have been working away in the background as usual. You often spring these updates on us.

I need to make one of those threading tools. A few years back there where a few versions of them including Johns.
It would be nice if you could do a post just on the threading tool to show how it's made and how it works for members here, as it will get buried here.

Those clamps look great, can we get a close up of those stainless threads, but I enlarged the photo but cant see them. I have a few older ones I use a lot.

With your center thats good to know about the hardening in them. I bought the ozmestore 7pc set, but had to send the first set back (at there expense) as it had a mile of run out. The one I received in replacement run dead true, so it must have been a one off.
I have found it useful for all sorts of jobs that are difficult to hold.

Dave

Hi Dave,
The threads are 10mm diameter * 1mm pitch and are 4.8" long being made out of 316 Stainless I thought this would be a good test. As you know this material work hardens pretty easy and cutting a long thread lets it move around a bit. I cut them at 100 RPM and used flood coolant (oil in my case) to keep the temperature under control, I also did not do any spring cuts until the end as rubbing would only make it harden. Before starting the threading I cut a grove in the bar at the chuck end a little deeper than the thread depth, set up the lathe for threading and noted how many turns the chuck revolved after turning it off, I then hand wound the chuck backwards to the point where I cut the power plus half a turn to allow for reaction time-getting slow in my old age and then zero the DRO. By doing this I could leave the oil flooding all the way during threading and ensure the threading tools carbide tip was free of the work before reversing and save me from breaking the tip of by stopping in the cut. This tool is very good to use as you only have to start and stop the lathe in forward and reverse and by timing the stopping point at the chuck end you can let it almost stop before engaging reverse so that it puts very little load on your gearbox. With the extended nose live centre on the tailstock end I let the lathe come to a stop before reversing.The cutting tool automatically lifts up when you go into reverse and drops down under it own weight at the other end of the thread, all you have to do is add the next depth of cut as it is reversing. I use the cross slide only for threading with this tool.
From the pictures you can see how the tool is made, I used one of my light duty tool holders for it. The vertical rod through the front of the tool is 4mm diameter stainless steel and the pivot point allen bolt is 6mm diameter. I used a piece of a coke tin 0.005" thick as the rear washer just to eliminate any drag on the tool when using it. All bolts are loctited in with one of the lower grades 222 I think. I cut the slot in the tool shank with a 4mm carbide end mill but it was not that hard.
This link has a few different versions on it and a couple of videos showing it is use. I hope the thread photo is OK as it is a dull day here again. I had another look at your tool holders posting last night, that was a marathon project Dave great work.

Bob

Those threads look great close up, thanks for the extra pictures and the right up.

I have been wanting to make one of those tool holders since they where all the rage over on Madmodder a few years back but it's one if them get around to it jobs.
Hopefully in the near future I can make one out of the spare holder I have. There where a few ideas of a pin, wedge etc, so not sure which one I will go but I like the pin idea.

That threading tool holder came out really nice, I take that is linished finish on the side?

Dave
PS you forgot the link

Originally Posted by krisfarm

Hi Dave,

I cut them at 100 RPM and used flood coolant (oil in my case) to keep the temperature under control, I also did not do any spring cuts until the end as rubbing would only make it harden.

Bob

Hello Bob.

Two things stood out in your post, the typically well executed work and your use of oil as flood coolant. Coolant has been discussed ad nauseam with most users favouring soluble oil in water. I don't want to use the later because of my infrequent use of some of my machines. My mill has an integral tank cast into the base which would probably become an ameoba aquarium if filled with soluble oil and water. It's a long while since I've turned the thing on. I'm not sure when I'll turn it on next.

So... what's the oil you are using?

Bob.

Hi Dave & Bob
You are right Dave I left out the link http://bbs.homeshopmachinist.net/sho...php?t=38585but
I chose this design for two reasons, firstly I had the tool holder made and I could use the front hold down bolt hole- 8mm and just put a 4mm stainless pin in a bolt and use that. I also liked the idea of having the side load covered, not that it is high for when you reverse. When cutting a large diameter thread say 50mm or more the tool has to raise up a fair way when reversing and the full length vertical rod offered I felt better security. I did give that tool holder a quick hit on the belt sander, but i did not have a fine belt to finish it off with-more things to buy.
Bob, I used to have the soluble coolant in my mill and lathe but did not like it as the water would be constantly be evaporating. By adding more water you had no idea of your mixture rate and I started to get staining and minor rust spots. Plus that soluble oil costs a packet. I swapped over to using automotive transmission fluid, an old friend of mine who was an industrial chemist told me years ago that the auto transmission fluid is one of the first cuts that the refineries take out of the crude and is a high grade oil.He used to get second hand oil from the transmission service people run it through a fine filter and mix it one third oil to two thirds diesel and run his big bus camper on it for years. I did use it for years as well on my farm l in my tractors.I made up a pump/filter set up and got 80 litres of relatively clean transmission oil from the local auto transmission service guy and changed over. It has stopped the rust/ evaporation problem. It may not in theory be quite as efficient as water for cooling but I prefer it. As for cost- no dollars just a bit of your time.
Bob
Ps Bob just reread your post again and noticed your comment about the cast tank in your mill, mine is the same. It took me a days to get my cast iron tank clean all that gung that grows in that oil water mix. Another reason to give it a big miss.