Just bought a Fortis lathe

[GraemeVW]

What a day!
Why do I always do this? I always think, no, I won't get it blasted, I'll strip it myself.
It's ALWAYS way more work than I think and blasting is cheap really!
But anyway, it's hand scraped back to whatever the indestructible red primer coat is.
Just wanted to get most of the top 5 layers of paint off before swapping to wire wheel/stripping disc/da.
Surprisingly rust free really.

Need to decide how I can raise it 7" in the neatest way.

 

[Jelly_Sheffield]

Need to decide how I can raise it 7" in the neatest way.

High strength concrete blocks underneath the feet with a decently thick steel pad for each of the feet to sit on, spreading the load is effective and doesn't break the bank.

It could be executed far neater, but jacking a 1.8 tonne machine up 9" onto blocks alone was enough of a challenge that I was happy with it just being secure.

Just be mindful of the center of gravity and if it seems top heavy consider anchoring it in some way.

 

[GraemeVW]

Been chatting with another fortis lathe owner. It seems the bed on these lathes usually has a removable V. I think tonys site also mentions this.
On mine the V way is cast into the bed.
I'm wondering why they changed this.
Is a removable way better or worse than one cast in?
I'm wondering if mine is early, and they changed it to removable for better accuracy, or easier manufacturing etc. Or if mines late, and they changed to it being part of the bed casting as an improvement.

 

[GraemeVW]

Another thing that puzzles me is the tool holder. This is going to show my inexperience with lathes!

I don't tend to have any preference for compound slide angle when doing normal turning, unless it's going to get in the way of the tailstock.
As long as the tool is 90 degrees to the work, then fine.

This lathe has a rotating 4 way tool holder bit it's also pegged. So loosen the handle, raise the tool holder, and rotate for each tool. This means the tool always has to be inline, or 90° to the compound slide.
So if I wanted to have the slide at say 30°, I can't have the tool at 90° to the work.
What's that about?

 

[Seadog]

That's a conventional 4-way tool post.

 

[GraemeVW]

That's a conventional 4-way tool post.

Ok.
So you always have the compound inline, or at 90°? Unless cutting an angle.

I don't, but I've read alot of machinists saying they keep the compound at 30°. I'm not super sure why, I think as you can then advance the compound instead of the cross slide for finer adjustment using the scales.
But that wouldn't be possible with this tool post would it.


Edit, I haven't taken it apart yet, but it also looks like the tool post spindle was set up for some kind of one way gathering spring and ball system. That's not there anymore. I'll know more when I take it apart.

 

[E T]

The 30 or 29 degrees is for single point threading. Less tool pressure than straight in.

 

[Seadog]

They are generally one way. Undoing the clamp turns the post one position anti-clockwise. As you tighten it, the post is totaled against a stop before being locked in position. The reason for the offset is that you can get a finer feed on the compound than if it were at 90°.

 

[GraemeVW]

They are generally one way. Undoing the clamp turns the post one position anti-clockwise. As you tighten it, the post is totaled against a stop before being locked in position. The reason for the offset is that you can get a finer feed on the compound than if it were at 90°.

Finer feed is what I thought. But I can't offset the compound can I, as the tool can't be set to 90° again.

I'm not sure if this will be an issue in reality. I'm just used to being able to put everything wherever I want. Even if there was no need for me to do so.

 

[GraemeVW]

It Seems this tool post is the same as a colchester maybe. Watched a short video on how it's indexed. Mine must be missing some parts though. It's not the original compound slide, but I don't think its colchester either.
I'll investigate further down the road.

Edit... think the compound slide is roundhead colchester triumph.

 

[Jelly_Sheffield]

Finer feed is what I thought. But I can't offset the compound can I, as the tool can't be set to 90° again.

I'm not sure if this will be an issue in reality. I'm just used to being able to put everything wherever I want. Even if there was no need for me to do so.

You can, but you just can't use the pin to index it, the toolpost should be secured by the clamping force from the handle on top, even without the indexing pin.

Whilst you've got the machine in bits it's possible to drill additional indexing holes for other angles if desired either in the topside for use with the pin, or in the toolholder for the spring detent mechanism if you reinstate it, you just have to be careful.



As an aside whilst people use 29.5° or 27° for supposedly better threading, if you actually set the topside to bang on 30° (using an angle block or such), then the trigonometry means that for each 1 thou you advance the topside, the tool moves inward by ½ a thou; you can also use 14.48° for a 1:4 reduction or 5.74° for a 1:10 reduction, if you can acquire a suitable gauge or accurate protractor.

It's not particularly common because it's a pain to set up but can be a good trick to get out of trouble when you need to turn something down to a very tight tolerance and being able to take a measured final pass that's very small indeed could make or break the whole job.

 

[GraemeVW]

You can, but you just can't use the pin to index it, the toolpost should be secured by the clamping force from the handle on top, even without the indexing pin.

Whilst you've got the machine in bits it's possible to drill additional indexing holes for other angles if desired either in the topside for use with the pin, or in the toolholder for the spring detent mechanism if you reinstate it, you just have to be careful.



As an aside whilst people use 29.5° or 27° for supposedly better threading, if you actually set the topside to bang on 30° (using an angle block or such), then the trigonometry means that for each 1 thou you advance the topside, the tool moves inward by ½ a thou; you can also use 14.48° for a 1:4 reduction or 5.74° for a 1:10 reduction, if you can acquire a suitable gauge or accurate protractor.

It's not particularly common because it's a pain to set up but can be a good trick to get out of trouble when you need to turn something down to a very tight tolerance and being able to take a measured final pass that's very small indeed could make or break the whole job.

There are 2 pins facing up from the top of the compound slide. Without checking I'd say they are about 1/2" diameter and 1/4" high. Once I undo the top clamp I have to lift the tool post off the pins and rotate it.
If I set it anywhere other than 90° it will be sat up on those pins.

Although this looks to be a colchester set up, I couldn't see those pins in the colchester diagram.

Am I being dense?

 

[E T]

Judging by the first picture in the OP it looks like you will never get the tool on centre height.
The toolpost is sitting way to high on that thick compound slide.
Or is that just the angle the picture was taken?

 

[GraemeVW]

Judging by the first picture in the OP it looks like you will never get the tool on centre height.
The toolpost is sitting way to high on that thick compound slide.
Or is that just the angle the picture was taken?

It's just the angle. I'd took the compound off to clear straps when transporting it. It's sort of just balanced on the back in that pic.

I haven't checked properly, but it looked like tool height, from the base of the tool mounting slot, will be about 30mm!

It had been used not long before I picked it up, believe it or not.
You can see there are 2 tools stacked in the tool holder.
If anything, I'll be struggling to get the tool high enough.

 

[GraemeVW]

To give more of an idea, this is the original compound

 

[Jelly_Sheffield]

There are 2 pins facing up from the top of the compound slide. Without checking I'd say they are about 1/2" diameter and 1/4" high. Once I undo the top clamp I have to lift the tool post off the pins and rotate it.
If I set it anywhere other than 90° it will be sat up on those pins.

Although this looks to be a colchester set up, I couldn't see those pins in the colchester diagram.

Am I being dense?

Oh, that's quite different to how it's "normally" set up, I can see why it's giving you an issue!

Given it's not in the drawings I would guess was done by a previous owner of either the Fortis or the donor Colchester after the original spring detent mechanism failed.

In a standard Colchester setup there's a spring loaded round pin in the topside with a bevel ground on top, and holes in the bottom of the toolpost.

Such that you can turn the toolpost clockwise freely, but the when a counter-clockwise force is applied the pin will drop into one of the holes and lock it from being pushed back, as shown in this video..


The alternative way to do it, which seems to be more common in the US, is to have a hole in the topside and several through holes (which line up with it) in the toolholder, allowing you to insert a close-fitting pin as a lock, or pull it up and have rotation unlocked.

Both of those approaches allow you to set intermediate positions between the locking holes freely, whilst the current setup on your machine definitely can't do that.



In your shoes I would probably modify it to use one of the other two methods of locking, as you will inevitably want to turn a tapered item at some point.

How you could do that would depend on:
• if the original recess for the sprung locking mechanism is still there,
• if you're considering fitting a quick change toolpost in the future, and
• if so what type of toolpost you'd choose.

But there's never going to be a more convenient time than now when you have it all apart anyway to figure out if its something you want to do, and how.

 

[GraemeVW]

Oh, that's quite different to how it's "normally" set up, I can see why it's giving you an issue!

Given it's not in the drawings I would guess was done by a previous owner of either the Fortis or the donor Colchester after the original spring detent mechanism failed.

In a standard Colchester setup there's a spring loaded round pin in the topside with a bevel ground on top, and holes in the bottom of the toolpost.

Such that you can turn the toolpost clockwise freely, but the when a counter-clockwise force is applied the pin will drop into one of the holes and lock it from being pushed back, as shown in this video..


The alternative way to do it, which seems to be more common in the US, is to have a hole in the topside and several through holes (which line up with it) in the toolholder, allowing you to insert a close-fitting pin as a lock, or pull it up and have rotation unlocked.

Both of those approaches allow you to set intermediate positions between the locking holes freely, whilst the current setup on your machine definitely can't do that.



In your shoes I would probably modify it to use one of the other two methods of locking, as you will inevitably want to turn a tapered item at some point.

How you could do that would depend on:
• if the original recess for the sprung locking mechanism is still there,
• if you're considering fitting a quick change toolpost in the future, and
• if so what type of toolpost you'd choose.

But there's never going to be a more convenient time than now when you have it all apart anyway to figure out if its something you want to do, and how.

Yes, I thought it was a little restrictive.
I've not taken it apart at all yet so no idea what's really going on. It could well be supposed to do something different but bits are seized.

I ha e a few projects on the go so I'm trying not to take too many assemblies apart yet. The headstock is apart, that's enough for now.

Plan is to get the cabinet, bed, and headstock painted. A raising platform made, and get that lot reassembled. Once I've done that I'll strip and sort the gearbox, red or, then stip and clean the carriage, refit etc etc.

Means it will be a while before I take the compound apart, unless I get super curious.

No plans to replace with a quick change, unless I have to throw money at this one, then I may as well.

If I just remkoved any indexing at all, so it can just be clamped wherever I want, that would work ok right?
Can't see why that would be an issue.

 

[Jelly_Sheffield]

Yes, I thought it was a little restrictive.
I've not taken it apart at all yet so no idea what's really going on. It could well be supposed to do something different but bits are seized.

I ha e a few projects on the go so I'm trying not to take too many assemblies apart yet. The headstock is apart, that's enough for now.

Plan is to get the cabinet, bed, and headstock painted. A raising platform made, and get that lot reassembled. Once I've done that I'll strip and sort the gearbox, red or, then stip and clean the carriage, refit etc etc.

Means it will be a while before I take the compound apart, unless I get super curious.

When you do get round to it, it sounds like either:
• Parts 19-24 in the exploded diagram below have been replaced with solid pins.
• Parts 19 & 20 have been refitted so badly in the past that they're sat proud and the machine was modified to match.
• Part 22 is seized solid so badly that you can't tell it's meant to move anymore.

Edit:

If I just remkoved any indexing at all, so it can just be clamped wherever I want, that would work ok right?
Can't see why that would be an issue.

Depends how well the clamping mechanism grips really, if it's still working even a fraction as well as they do when new it will be fine for all normal operations (and many abnormal ones, anything other than really aggressive knurling with a push knurl or using huge form-tools really).

The worst that would happen is you might find it's mildly annoying to have to set the toolpost square to the chuck each time the toolpost is rotated to switch tools.

If the clamping mechanism is badly wallered out, then you might run into issues... But short of the previous owner being a 300kg gorilla with a real penchant for using scaf-pole as a cheater on everything they touch, I just can't see that kind of wear and tear being likely.

 

[GraemeVW]

When you do get round to it, it sounds like either:
• Parts 19-24 in the exploded diagram below have been replaced with solid pins.
• Parts 19 & 20 have been refitted so badly in the past that they're sat proud and the machine was modified to match.
• Part 22 is seized solid so badly that you can't tell it's meant to move anymore.

View attachment 398901

I found a different diagram

I think it may be this one, but year, with a pin stuck.
I assume there should be a spring to lift the tool post too.

So, in use, it will index on the pins, or push the pins down out the way if being indexed at something other than 90°, just means you haven't got a locator telling you your quickly at the right angle.

 

[Jelly_Sheffield]

I found a different diagram

View attachment 398902

I think it may be this one, but year, with a pin stuck.
I assume there should be a spring to lift the tool post too.

So, in use, it will index on the pins, or push the pins down out the way if being indexed at something other than 90°, just means you haven't got a locator telling you your quickly at the right angle.

Looks like they changed the position of the sprung bits at some point, but used the same parts in a different position.

I don't think there's a spring to lift the toolpost, the ramp on the sprung pin (2 on your diagram) should let the toolpost itself stay sat flat on the surface and just push the pin down when it's turned clockwise.

The sprung Ball Bearing bit which is opposite the sprung pin assembly on your diagram, should engage some little divots on the base of the toolpost to give you a less precise indexing option for angles other than 90°