Lathe Rigidity Testing (determine upgrade benefits)

[whydontu]

Good stuff.

Doesn't your lathe already have locks?

FWIW, I've been holding off of putting a DRO on my lathe. I've used lathes for over 20 years without one and done just fine. I'm not sure the pain is worth it.

But I would put a DRO on my mill again in a heart beat!

I have a number of concerns on the lathe.

1. How to mount a scale on the cross-slide that won't interfere with the tailstock when I'm drilling.

2. How to mount a scale on the bed that won't interfere with a taper attachment.

3. The DRO I have on my mill has a lathe mode. The lathe mode has an automatic calculation for the compound angle setting. Very attractive. But the compound is small. How do I mount a scale on the compound without getting in my own way? I wish they made a teeny tiny scale for that.

Anyway, my point is really that I'd be focussing on my lathe technique and tooling before I worried about installing a DRO.

In my mind, my lathe priority is an upgraded VFD Ready motor so I can get speeds under 70rpm.

But who knows, after I put a DRO on my lathe I might wonder how I lived without it. Which is pretty much how I feel about the DRO on my mill.

So many ideas! Every time I surf CHMW I get sent down a rabbit hole of things to do.

#1 - I have the DRO scale mounted on the tailstock end of the cross slide. It adds about 3/4” of width, so the tailstock can’t get as close to the chuck. <However>, going to the fixed eccentric toolpost means I can swivel the eccentric outboard and move the cross slide right up against the headstock.

#2 - on my BB 10x18, the cross slide extends past the back of the bed. The DRO reader mounting bracket is connected to the base of the cross slide, with the DRO scale mounted underneath the bed rail overhang. I don’t think it would foul a taper attachment.

#3 - I don’t use the compound, so I don’t need a scale. I think the slim glass scales could be fitted to the inner face of a cross slide. It probably wouldn’t interfere with the cross slide use, it would be hanging underneath the tool bit projection.


And now for the new project. My DRO cross slide scale covers up the carriage lock that’s on the tailstock side of the cross slide base. So when I want to stop the cross slide from moving, most of the time I just engage the half nut with the lead screw disconnected from the lead screw gears. It’s not very rigid. But Dusty’s 8:00 AM post showed me a solution. Just fabricate a lock plate, and drill the headstock side of the cross slide base.

 

[Susquatch]

So many ideas! Every time I surf CHMW I get sent down a rabbit hole of things to do.

#1 - I have the DRO scale mounted on the tailstock end of the cross slide. It adds about 3/4” of width, so the tailstock can’t get as close to the chuck. <However>, going to the fixed eccentric toolpost means I can swivel the eccentric outboard and move the cross slide right up against the headstock.

I think what you saying here is that you eliminate the loss of space by tucking your cross slide under your chuck. It's a good solution but I like my tool post and it would be a pain to remove it whenever I needed to drill something. So I dunno about this solution.

#2 - on my BB 10x18, the cross slide extends past the back of the bed. The DRO reader mounting bracket is connected to the base of the cross slide, with the DRO scale mounted underneath the bed rail overhang. I don’t think it would foul a taper attachment.

That would not work for me. My saddle does not overhang the base.

#3 - I don’t use the compound, so I don’t need a scale. I think the slim glass scales could be fitted to the inner face of a cross slide. It probably wouldn’t interfere with the cross slide use, it would be hanging underneath the tool bit projection.

I'm terrified of hanging a scale right where my work is being done. But ya, that would work.

 

[Tom Kitta]

Y axis behind cross slide, removes about 20mm or so of drilling capacity. X scale on the back side. Taper attachment would need to be designed to go around this somehow or scale would need to be very low.
On smaller lathe you will loose some capability with a DRO install, but DRO adds so much more that it is 100% worth it.

 

[gerritv]

I think this thread has wandered off topic.

What was/is it that makes you think your lathe is not rigid? Are you hogging .25" cuts and it can't handle it? Are you trying to get a small lathe to behave like a bigger one? Are you upgrading the motor to provide the power to do deeper cuts?

By installing a Type A Multifix, you have added a 48mm lever from the cutter to the toolpost bolt. On a small compound that will add to your problems, not reduce them

A DRO won't help with rigidity

A bigger cutter holder likely won't do much either, esp with the 48mm overhang. Your compound mount to the cross slide will not deal with it. And you will promptly run out of tool height to centre of work.

If you take the time to watch what Tryally does with a Sherline and a 6 or 8mm diameter HSS cutter on a 0XA style tool post you will see that the additional expenses you are incurring are not necessary to get things done. Work with what the lathe can do, use sharp HSS tools

By way of comparison, this is the toolpost that Stefan was using on a 10x22 lathe, your A Type is bigger than that on a considerable smaller lathe.

 

[Susquatch]

removes about 20mm or so of drilling capacity. X scale on the back side.

It isn't the loss of travel that concerns me. I like to bump my tailstock against the saddle as a quasi tailstock stop. It allows me to vastly reduce the amount of cranking on the tailstock Quill between operations. I couldn't do that with a DRO in there.

I think this thread has wandered off topic.

Ya, the DRO is off topic but it was being discussed by the OP as an alternative priority to improving rigidity. I think that makes it ok.

 

[140mower]

It isn't the loss of travel that concerns me. I like to bump my tailstock against the saddle as a quasi tailstock stop. It allows me to vastly reduce the amount of cranking on the tailstock Quill between operations. I couldn't do that with a DRO in there.



Ya, the DRO is off topic but it was being discussed by the OP as an alternative priority to improving rigidity. I think that makes it ok.

While we are still off topic, could you drill and tap a hole in the face of the tailstock base and insert a bolt to act as a stop about a 1/16" before impact with the scales?
Just a thought, might be like many of my other "good" ideas that don't get past the "cutting room floor"..

 

[Dabbler]

I couldn't do that with a DRO in there.

insert a bolt to act as a stop about a 1/16" before impact with the scales?

It is alos common to bolt a shield on your cross slide that is rigid enugh to take the 'bump of the tailstock. Either way, the tailstock 'bump' can be acomodated.

-Why I never did this was the loss of drilling depth on my small lathe. On my larger lathes, this is not a problem - so a DRO may well be in my future...

 

[opensourcefan]

I think this thread has wandered off topic.

I'll be honest with you, I liked it's off topicness more than your post. You are writing from a sour negative point of view. Your comments aren't absolutes and the reality of each has more to be considered. You only offerd one line of neutral advice. Your DRO comment set me off and is indicative of your mindset when writing your post.

Re the Multifix lever, if you want to talk physics I'd be happy to engage, that is my training. The Principal Direction of Force in this situation lowers the 48mm moment that you eluded to.

 

[gerritv]

How is my post sour? You go on about trying to make a lathe more rigid, and then segue into DRO. If you can't deal with the advice, based on experience with lathes from a Unimat to now a 1022 BTW, then you shouldn't ask.

I hope you enjoy the journey, not sure where it will take you though but I'm sure it will be interesting to follow.

 

[opensourcefan]

How is my post sour? You go on about trying to make a lathe more rigid, and then segue into DRO. If you can't deal with the advice, based on experience with lathes from a Unimat to now a 1022 BTW, then you shouldn't ask.

What advice did you provide? Use a smaller tool post and that a DRO won't help rigidity? Experience is one thing, being able to convey it in a useful manner is another.

I hope you enjoy the journey, not sure where it will take you though but I'm sure it will be interesting to follow.

You see, you just can't help it. Such a rude comment and we don't even know each other.

 

[Tom Kitta]

It is alos common to bolt a shield on your cross slide that is rigid enugh to take the 'bump of the tailstock. Either way, the tailstock 'bump' can be acomodated.

-Why I never did this was the loss of drilling depth on my small lathe. On my larger lathes, this is not a problem - so a DRO may well be in my future...

I have two bolts in there for that purpose. Do not want to slam the tailstock into DRO accidentally and shields are huge and would take like extra 20mm or more.

Actually I just checked and I lost ZERO drilling capacity for drills over around 1/4" . The tailstock tube normally extends over an inch and then there is the chuck body plus drill length. Unless using very short drill such as center drill my tailstock will not bump into bolts protecting DRO before it bumps into the work piece.

Dabbler, you may do measuring on your lathe as well, use say 3/8 drill bit and see whatever you can touch work with say tailstock tube fully retracted and with say 20mm spare - if yes, DRO for most drills will not have effect on drilling ability.

Besides, how deep do you plan to drill with smaller drills. My tailstock tube extends just over 3".

DRO would be more of an issue installed this way on large lathe - but on the large lathe there is space elsewhere for it - so no issue.

 

[Susquatch]

While we are still off topic, could you drill and tap a hole in the face of the tailstock base and insert a bolt to act as a stop about a 1/16" before impact with the scales?
Just a thought, might be like many of my other "good" ideas that don't get past the "cutting room floor"..

Actually, I like it. But I'm thinking a bumper on the cross slide might serve the same purpose and protect the scale even better because it can be better located. Only the loss of repeatability would stop me.

I like how one good idea leads to another.

 

[Susquatch]

It is alos common to bolt a shield on your cross slide that is rigid enugh to take the 'bump of the tailstock. Either way, the tailstock 'bump' can be acomodated.

-Why I never did this was the loss of drilling depth on my small lathe. On my larger lathes, this is not a problem - so a DRO may well be in my future...

I could NEVER put a scale in there without a shield. So I think you may be onto something there. Like the bumper as an off shoot of @140mower 's suggestion, I think that a separate but robust shield is yet another step forward!

Edit - English sucks. By separate I mean not attached to the DRO scale in any way. By robust I mean can handle bumping with the tailstock.

 

[Dabbler]

Dabbler, you may do measuring on your lathe as well,

I like your lateral thinking, but you have missed my point.

The way I work, with the drilling I do, from #40 all the way to 1", I could find all kind of work-arounds to allow the DRO and shield, bit I choose to have full drilling capacity instead of having a DRO.

Yes I can buy long series drills, Yes I could buy a longer chuck arbor combination, but to me it just isn't worth it. I really do not like stick-out, on the work or on the quill. It increases flexibility (vibration) and magnifies inaccuracies in the lathe chuck or the tailstock chuck. I keep everything as compact as possible.

On my bigger lathes, well, that is another matter: longer quill reach, better access to the chuck because of longer overhang on the tailstock. easy-peasy.

After all, we are talkng about rigidity here as the *primary* focus...

 

[whydontu]

Being the rule follower that I am, I started a new thread called "Lathe Rigidity Testing Segue To DRO" with photos that demonstrate my solutions to most of the DRO, crosslide, tool post questions raised in this thread. I didn't add anything about rigidity, since my BB B2227L CX708 has one aspect that quite a bit different than most of the smaller lathes - the bed is quite solid, no arches on the front of the bed. Flat cast iron from top to bottom over the full length of the bed. Lots of beefy ribs between the front and back. Fiddly to install because I have to make sure the bench surface is flat everywhere, not just at the mounting points.

 

[Dabbler]

@whydontu I love your lathe! it seems very well built...

 

[Susquatch]

Being the rule follower that I am, I started a new thread called "Lathe Rigidity Testing Segue To DRO" with photos that demonstrate my solutions to most of the DRO, crosslide, tool post questions raised in this thread.

What rule?

See you there!