Making small gibs

[Vince]

Anyone got any tips on making small gibs?
I need to make a couple, 2.5 inches long, .300 wide, and .200 thick.
I started milling last night and thought I would mill one gib a little over 5 inches long and then cut in half.
The problem I ran into was warping. I might be using the wrong material I don't know.
I was using a piece of key stock.
Any tips would be appreciated.

 

[chips&more]

I have made several small gibs of the size you are trying to make. I’m not the expert on metal choice, but I use 12L14. Mainly because it has lead in it and I’m thinking it will help with lubricity. It also has less tenancy to warp. Been rough milling to shape and size. Then over to the surface grinder to finish up…Good Luck, Dave.

 

[kvt]

most even small ones that I have seen looked to be made of cast.

 

[Bob Korves]

Cast will give you much less issues with warping, but it can be difficult to find an appropriate piece of stock to work with. Cast is also prone to breaking if you are not careful with it. Once installed, cast is very good and quite stable, cast iron against steel has low friction. I assume they are parallel gibs, not tapered? On taper gibs, and of flat gibs as well, a surface grinder and/or scraping will be useful to get a good fit.

Edit: gibs can be made of brass or bronze as well.

 

[Vince]

I don't have any cast readily available. I do have some oil impregnated bronze though.

 

[4GSR]

Small gibs like that, I generally start out with material already on size, for the thickness, like flat ground stock. In your case, this won't work. On the width, if you have a 4 x 6 bandsaw, start out with a wider piece of material than needed and push the material thru the bandsaw to make a strip wide enough for the gib.
If it is a dovetail gib, get you a angle vise to hold the piece in to cut the dovetail edge needed. Going back the the thickness needed. To do it right, you almost need a surface grinder, of course to may, this is not an option. So what you have to do is take a little off of one surface, flip it, take a little off the next surface. And keep doing this until you get the thickness needed. Try not to take deep cuts, keep them around .015". Yeah I know, lat of wasted time. But to keep it from warping this is what you have to do. Use a good sharp endmill or a good sharp fly cutter. Try to stay away from using a insert type of face mill! There's always exception to the rule.

 

[john.oliver35]

I made a couple of small gibs recently for my little Sherline lathe. I started making rectangular brass stock a little bigger than maximum thickness. The Sherline gibs are tapered dovetails 55.5 degrees on the ways, and they mate to the carriage into a 45 degree socket. I designated one of the flat sides as the mating/sliding surface to ride against the ways and milled all the angles with reference to this surface.


The 'top' and 'bottom' edges of the gib were then cut at a 55.5 angle so they would be parallel to each other and align with the top and bottom of the ways.

I put the sliding surface down onto a sacrificial piece of material and fastened them together with some recessed #4 flat-head screws. This was mounted in a vise at an angle of 0.1" per foot (which is, as close as I could measure, the taper in the Sherline gibs using a sine bar to align. Then tilted the head of the mill 10.5 degrees (55.5 - 45 = 10.5). Milled the side opposite the sliding surface with a sharp fly cutter. I added an aluminum 'fence' to help hold the gib, shown clamped onto the sacrificial piece below:




I also had to taper 'pointed' tips of the gibs so that they would seat into the milled 45 degree corner of the carriage (not shown) . I finished up by flattening the non-sliding surface on a diamond stone and checking on a surface plate. The gib was fit to the lathe by rolling Dykem Prussian blue onto the ways, tapping the gib into place, removing then scraping the high spots. Repeat this last step a jillion times and I got a nice fit to the lathe.

 

[Vince]

Thank you for the replies. A lot of good information here.
When I get back next weekend I will see what I can do.
Thank you again for the replies.