Sorce for 1" chromed rod?

have you looked for barbell bars at sports stores? they are 1", I believe.

i

What you are looking for is Thompson rod or the equivalent. Try

to get an idea of what is out there. I would try your local bearing house first. Try some searches on linear bearings, case hardened shafting, etc. Be sure to check out seals and maybe even covers for the shafts to keep crap out of the bearings. Are you using OPN type bearings of full, Rolling element or plain? There is a lot of permutations out there and getting all the right parts that play together nicely will ease the assembly and the reliability of the system. lg no neat sig line

Check with outfits that rebuild hydraulic cylinders. Could be they have it on hand. Just a thought, don't know that they do.

Harold

cylinder repair components in Alabama

will cut and ship

but chrome rod is not really what you want

you want predrilled and tapped Thompson rails and supports

if the load is light enough you can use the extruded aluminum that is all one piece and hard anodized

mcmaster has all of this product

I suspect weightlifting bars wouldn't be accurate enough, though maybe it's worth a look if you have a fair amount of adjustment. What I've looked at plays pretty loosely with size tolerances.

8' of 1045 1" TGP for 64.59+S&H

8' of 1018 Cold Finish for 26.81+S&H (not ground, so I don't know if that will work for you). They also have 17-4 TGP stainless for

101.06+ /8'.

(2) 4' lengths of CF 1018 for 36.31+ (same caveat). They also have SS 303 TGP, but it's 122.28+ for (2)x4' (neglible difference in price between 1x8' and 2x4').

't list prices for their regular stock online, and the only TGP I saw in their "drop zone" was 2".

TGP in 1018 and 1045, but again, doesn't list prices online.

HTH, --Glenn Lyford

MSC stocks it, case hardened or chromed. Chromed is spendy.

Why chrome plated? McMaster has Thomson (no "p") shaft on p.958 in lengths to 96". Prices from a bearing house should be about 15% less.

Ned Simmons

Any I ever came across were slightly over 1", crusted with scale, and made from some of the nastiest steel on earth - probably just non deformed re bar. Gerry :-)} London, Canada

These are Thomson SPB-16 linear pillow blocks with open bottons. They are intended for a pre-drilled and supported shaft which would be nice but I was hoping to find something a little cheaper. After all. if they cost more than $100 I have just about doubled my costs. :-)

Guess I will have to call Nook in the AM and see what their off the shelf rod costs.

I missed that. The plain rod is fairly reasonable but the pre-drilled is kinda pricy. Wish I could get $90 for drilling and tapping seven 1/4-20 holes.

I will have to do some price shopping in the AM.

Several years ago I was in the market for some Linear bearings and such, Ebay had some pretty good deals.

Chuck

Here's your chance. A penny saved... The hard case on Thomson shaft comes off easily with carbide tools and the core machines nicely as well.

Ned Simmons

McMaster does have chromed suitable for linear applications as well as hardened, depending on the spec its about $60 per 48" lenght for the standard and increasing....

Drill rod is not really a good alternative as the spec is +- the nominal whereas proper linear shafting is -.

The open supported bearing is great but beside the additional cost of the tapped shaft also check the price of the supports. I'd do the math and see if I could get away with just the enclosed bearings with end supported shafts.

Bernard R

I think I will go with the standard Thomson rails from McMaster and drill them on the mill.

I am using BeamBoy to do the deflection calcs (A great little program that disproves the idea that you can't get something for nothing) With an estimated gantry weight of 40 pounds, half on each rail at the 24" point, it came up with .0308. A bit more than I can live with. A support every 12" cut the deflection to .0004. Better than I will be able to line up during installation.

I'm thinking I could mill my own supports to an acceptable .001 out of some

3/4" aluminum bar stock.

Hey Glenn,

I was at my favourite ship chandler yesterday, and they had a nice rack of polished stainless steel "railing" in 8 foot lengths, including 1" nominal at $6 per foot (Canadian). I "rolled" it on the floor, and it seemed very straight, in that no matter how I set it down, it didn't assume the same position each time. Probably for bow pulpits and Biminis, and so maybe a bit light. Just a thought.

Brian Lawson, Bothwell, Ontario.

I have a BUNCH of polished stainless tubing for my pulpits and rails but they are not really strong enough to support the gantry. Also it was a hard fought battle to get that railing for the price I did and it is going on the boat. :-)