Lathe Mods

[Brass_Machine]

Alright... I have been inspired by Bogs, Darren and Websterz to mod my little 7x10 lathe. I could spend the money and get the 8x14 or the 10x22, BUT being who I am (and money considerations) I am going to mod my lathe. I want to get the 14" bed extension kit:



I am also going to replace the bearings in the head (got those part #s Darren) and mod the tailstock (quick release cam). True up my cross slide.

Now the big one which is the purpose of this post. I am pretty sure this can be done, but I want opinions. I am thinking about machining up a spacer .5" to 1.0 to fit under the head to increase the swing as well. I know I will have to mod the tailstock and possibly the cross slide. Those of you that have had this lathe apart... is this possible? Does it sound feasible?

Eric

[Brass_Machine]

Ahhhh.... I see a possible problem with the spacer idea:



the drive train. Doh 

Hmmm...

[Darren]

Eric, you might get enough movement in the bottom gear assembly to lift the headstock 1/2", maybe more.

If not just add an extra idler gear, but remember reverse becomes forward etc.

I'll look for those bearing No's later for you.

[Brass_Machine]

Eric, you might get enough movement in the bottom gear assembly to lift the headstock 1/2", maybe more.

If not just add an extra idler gear, but remember reverse becomes forward etc.

I'll look for those bearing No's later for you.

Cool...

I think I see ways to get that extra play for a spacer. Can't really check as I am at work and the lathe is at home.

Eric

[Stilldrillin]

Eric, you might get enough movement in the bottom gear assembly to lift the headstock 1/2", maybe more.

If not just add an extra idler gear, but remember reverse becomes forward etc.

I'll look for those bearing No's later for you.

I would like to know the bearing No`s if possible...... Please! 

David D

[Darren]

The bearing No' 30206JR for the inner race and 30206 J-N for the outer race. Those No's are all you need for any bearing supplier.
You do of course need two sets.

The spacer you need to modify is already on the lathe. I managed to shorten mine on my lathe before fitting it. When you get to that part you will realise what I mean. It's part of the bushing at the back of the spindle just under the pre-load nut. Just lathe it with no pre-load. Easy cos it's plastic, if it where metal I doubt you could do it without another lathe.
I had no choice at the time as I only had one lathe.

Hope this helps
Darren

[Brass_Machine]

The bearing No' 30206JR for the inner race and 30206 J-N for the outer race. Those No's are all you need for any bearing supplier.
You do of course need two sets.

So I need 2 of each right?

[Stilldrillin]

Thanks Darren!

Yer a Gent. 

David.

[Darren]

Yes, they come in sets. inner and outer race, you need two of them.  

[bogstandard]

Here I am again Eric, piddling on your parade.

Can you tell me the reason for the risers?

The reason being, if it is to turn larger items or fit a larger chuck, I honestly don't think the gear trains will take the pressure of the extra torque required to cut or swing larger items. They really are borderline.

If you look at the ML7 which has about the same swing as yours, they are regularly fitted with riser blocks. But if you look at how they are made, they can take the extra forces involved. Massive metal gears compared to yours, and a motor that is about 3 times the size.
These lathes are made down to a price, so everything on them is really at the max they can cope with. That is why when you go for a larger lathe, they start getting made stronger and stronger as they go up in size, and that is what you are paying for.

It is your choice, but honestly, for the extra work involved, and the suspect strength of the machine itself, I personally would accept it as it is, or if you want the larger size, spend your money on buying the next size up.

John

[websterz]

Bogs is right, the extra mass of a chuck over 4 or 5 inches alone, not counting the torque applied when cutting, would bring these little lathes to their knees. I upgraded to a 4" 3 jaw and it is about the biggest chuck I would try to run on my 7x12. You also have to consider that every inch you increase in work diameter you lose a half-inch of cross-slide travel. It's not worth the engineering headache to try and make these machines much bigger than they are. Just my 2 cents of course. I would pursue the other mods out there to improve the lathe's performance and move to a bigger one when the time comes.  Already, with less than 12 hours of actual work, my little lathe is 10 times the machine it was when I started and I haven't even begun to align the head and tail stocks to the bed yet. 

[Brass_Machine]

Alright... you guys made a good point. I really don't turn anything over 2" anyway. Savings account will be started.

Eric

[Darren]

Just to rub salt in the wound I'd have to agree. When you get to turning 3" dia you begin to realise you are pushing it....not just power wise but stability as well.