# What grit of Timesaver brand lapping compound should I use?



## Mini lathe owner (Nov 3, 2020)

Can anyone give me advice on the best lapping compound grit to use when lapping the cross slide and compound slide on my mini lathe.

I have heard that Timesaver is a good brand. Timesaver has a Yellow and Green line. The Green line is what is used on steel. My question is of the 4 grits that they offer,

Coarse: 40 grit
Medium: 80 grit
Fine: 220 grit
Very Fine: 320

Which grit would you recommend? 

If not Timesaver brand, what compound and grit would you recommend?


----------



## Cooter Brown (Nov 3, 2020)

I really don't think you should lap your compound ways that would remove all the space for oil.....


----------



## middle.road (Nov 4, 2020)

Try some searching on Youtube for mini lathe improvements.

This Old Tony has a series of videos on tweaking a mini lathe.

And there's this one also:


----------



## C-Bag (Nov 4, 2020)

Cooter Brown said:


> I really don't think you should lap your compound ways that would remove all the space for oil.....


Cooter is very right. You don’t mention why you want to lap your compound but if it’s for smoothness of operation lapping is not quite but close to the worst thing you could do for a number of reasons. More than likely you are seeing the machine marks on your dovetails and thinking it would work better without them. Believe it or not, they wouldn’t. Ever wetted two pieces of glass and stuck them together? You would think they should slide smoothly. Not so, they stick tight because of a phenomenon called stiction. Those machine marks actually help foil stiction but barely. The best is a process called scraping which makes a pocketed surface for oil and is a more precise way to make the dovetails more parallel. Non parallel dovetails and wear cause problems too.

The other problem with dovetails and lapping compound is it embeds into the cast iron and no amount of cleaning will get it out, only wearing it out. That’s why the best lapping plates are made of cast iron. This embedding is called “charging”.


----------



## Mini lathe owner (Nov 4, 2020)

Here we go....

I figured no one would actually answer my question.

Here is the situation. I have watched The Frank Goose detailed videos on how to set up your mini lathe and meticulously followed his instructions. My lathe is lubricated with a high quality oil and oiled often.

If the gibs are tightened in a way that allows firm but usable tightness in controls, the cross slide rocks enough to cause a catch. If the gibs are cranked tight on both cross and compound slide, there is no rocking, but it takes 2 hands and some sweat to turn the dials.

 As I am a novice, I do not have the skills or materials to make new gibs.  I do however have elbow grease. I have heard from others that lapping helped with ease of movement without play.

I doubt they are lying. 

I just want to know what compound to use. 

Anybody want to answer that question?


----------



## C-Bag (Nov 4, 2020)

Then the people to ask are those that say it helped.


----------



## middle.road (Nov 4, 2020)

Mini lathe owner said:


> Here we go....
> 
> I figured no one would actually answer my question.
> 
> .........................


I kinda did, even gave you some links for reference.
@C-Bag answered it in detail.
Two lapped surfaces will stick together, that's physics, that's also the problem with my 1440 cross-slide.
It came out of a plant that made granite counter-tops, wore the scrapping on the cross-slide, the stiction is annoying.

I've tweaked two 7x14's for acquaintances and both required reworking the gibs amongst other things. Sorry but that's the reality of it.
The cheesy gibs really bound up the cross-slide.


----------



## Mini lathe owner (Nov 4, 2020)

Can I buy better gibs? Or pay someone to make them?


----------



## Mini lathe owner (Nov 4, 2020)

Mini lathe owner said:


> Can I buy better gibs? Or pay someone to make them?


Or would it be possible to pay someone to scrape the cross slide and compound? Do you know anyone who might do it?


----------



## C-Bag (Nov 4, 2020)

I get you are looking for quick answers but most of us who own Chinese lathes have come to grips that they are really an assembled kit. And it’s a roll of the dice if there was something not done right and it’s up to us to fix it. And 99% of the time it’s something different on each machine.

The compound on my 9x20 lathe once I read up how to measure the dovetails accurately was so out I opted to buy a new one from Grizzly. It was like $40 if I remember right. The old one was some how twisted. The new one was way closer and could at least be deburred and some minor filing and is 100% better. I do need to go back and do some minor scraping. The gibs are fairly easy to check with a straight edge and clean up defects and burrs.

 Scraping is very time consuming but very rewarding and just like so much of our time is spent making tools and fixtures much time is spent fixing and tweaking our machine tools. It’s part and parcel of being a hobby machinist. You will notice on this site the shared knowledge here has a lot to do with fixing and improving machines.


----------



## tq60 (Nov 5, 2020)

A bit of work with files and sand paper can tune it up.

Clean all of the mating surfaces then with a Sharpie paint them and slide them together and then examine the surfaces.

Where ink gone it is rubbing and ink left not.

Careful work over time will improve it.

Lapping will ruin it.

Sent from my SAMSUNG-SM-G930A using Tapatalk


----------



## Weldingrod1 (Nov 5, 2020)

First, you should explore where in the travel is tight, and what shape your ways actually are.
One quick technique is to pull the gib, clean the faces and sharpie one side. Install the mating part (staying away from the sharpie). Slide the two parts together over their full travel, and remove without touching the sharpie. Look for where the sharpie is removed...
If you've got a high spot in the middle You could put a strip of PSA lapping film (or fine sandpaper) on the straighter side. Trim it off flush. A few strokes with lube and cleaning off the film could help pull down the high spot. You would want to handle it to control rocking too. It wouldn't be crazy to install the gib, assuming there was enough clearance; that would keep it from rocking. Look at the pattern! Dont try to go all the way at once! Pull the film off and re-spot with sharpie.
You could also alternate which side has film... 

High on the ends would be tougher but could be addressed the same way, and tapered would be the worst. You can look for taper by putting two round pieces (ideally dowel pins, but drill shanks could work) and checking the measurement across them over the length of the part.

Anyway, that's some thoughts based on your constraints.

Sent from my SM-G892A using Tapatalk


----------



## addertooth (Nov 6, 2020)

To answer your question, YES, Littlemachineshop.com sells improved Brass Gibs for the 7X12/14/16 lathes.   They are a step up from the steel gibs which come with the lathes.  They aren't priced too terribly high ($33.60).  They seem to improve the smoothness and reduce the amount of force required to turn the handle, for a given amount of tightness.  

They sell the brass gibs for both the cross feed and the compound.  

Brass Gibs for 7 by 12/14/16 lathes


----------

