Bolt only - no weld?
 

I thought I saw references to folks JUST bolting together a version of the MechMate, but after searching I can't seem to find any 'supporting' information.

Is there a 'bolt only' version? Or was I smoking something that I didn't know I was smoking?

If there is, could someone nicely point me to where I can RTFM (Read The Fine Manual ;-) ) about it?

Tia, ... JC

Hi Jack,

There aren't any "bolt together" plans. There are some of us that have modified the plans to make certain parts of the MM bolt together (a design that I don't believe Gerald necessarily agrees with). Flanges still needed to be welded to the ends of some of the parts to allow them to be bolted to other parts.
After finally completing my MM I'm not sure, if the need ever came up, if it would be more difficult to disassemble the "bolt together" unit or transport it as a whole. I think Sean may have a better idea as he recently moved his MM.

I hope this helps.

Greg

Hi Jack,

It is possible to make them bolted type. As Greg said you have to weld the flanges and use plenty of fasteners to hold them takes more money & time, not advisable because could loose rigidity if not done by a pro. Well see my thread to have a idea i have made my machine removable into two in case the mechmate is required to be relocated.

http://www.mechmate.com/forums/showthread.php?t=973

Vishnu

Jack, our last 5 tables are partially bolted together. (I am not against it in principle, Greg ;))

It depends on what your reasons are for bolting:
- Smaller pieces for transport, or
- dislike of welding?

If it is because of a dislike of welding, well, the gantry and y-car and z-slide all need some welding, so you can practice on some table welding. There are no critical welds - even a first-time welder should be able to produce adequate strength without affecting the cut quality of the final machine.

My MM is a screw, solder part.

I follow the plans as far as possible.

Welding is the best option :)

My reason is partly for transport/moving and partly because of lack of any welding skills. But I can get over the latter with some $$ and tinkering.

Welding is not so bad. You get better with practice and time.
On my machine you can tell what welds were beginning welds and what welds were done toward the end of the build. Wish I had spent more time Practicing before I actually started on the machine.

My base is a bolted/welded together base. It is 4 sections, 2 ends and 2 sides.

Attachment 3123
The #2 legs and the #4 pipes are welded to the #1 main beam. The long #3 pipe is welded to
the #2 legs and also to the #4 pipes. The #5 braces are welded to the #2 legs and also to the
#4 pipes, completing the welded side.

The #7 braces are welded to #6 pipes, almost completing the welded ends.
The ends of all braces have been flattened for ease in welding.

The #8 cross beams are bolted to the #1 main beams.

Attachment 3124
I made inserts for the ends of the #6 pipes, they are 1/2" X 1 1/4" X 1 1/4" with the corners cut
and a 1/2" tapped hole in the center. I recessed them in the ends of the pipes about 1/4" and
welded them all the way around, completing the welded ends.

The ends were then bolted through the #2 legs. This has made a very stout base.

Ok, I think I am convinced that 'even I' can do enough welding to get by, and I will probably learn to enjoy it. Now to put that into my build budget too :(

You can always rent a welder or trade a tradesman some time on your machine when its done for the welding. Good luck,

Tim

Hi,

I'm also weighing a few alternate design of the table structure, which i later find is not much different than the shopbot table design. the only difference would be that it will have the main longitudinal beam flipped (flange facing outside) and the feet will be attached to the main longitudinal beam on it's face instead of feet-top to beam bottom. go google shopbot PRT for images.

The guys at LumenLab (brainchild) in designing his RoBlok mentioned about bolt construction method where when 3 beam/tube each on different axis, is bolted twice (each bolt attach that tube to each of the other tube) it's a few time stronger. However some precaution step has to be taken, for example use wide washer and also use bolt with wide head.

Please note that all above, i haven't tried. I mean, don't take it like it's a sure thing. just ideas, see?

Welding the gantry shouldn't be much of a problem. If you're building 4 feet Y (that's like no more than 6 feet of gantry final length) it's worth the trouble putting it inside a car and take it to a welder.

Nikonauts, what the ShopBot guys don't tell you is that the dust collector foot collides with the feet/legs screwed to the inside of the main longitudnal.

:), i see. is it ok to widen the Y dimension to compensate that? could put stop further from the edge. it eats more floor space for sure but if bolted build is indispensible one could live with it. Mechanically/structurally is it inferior?

I've seen somewhere in this forum where someone attached an indexer to one of the legs, that looks fun. It's not like it's undoable when the leg is below the main beam. It just look proper when the leg is inside.

You just weld a small flange to the top of the leg and then bolt it under the longitudnal - that solves everything! But I can read that you are scared of welding . . . . . . ;)

well, ok. i'll give welding a shot. maybe. :p

The welding itself is not near as hard as all the grinding later to make it look like you knew what you were doing...:)

A couple tips from one novice welder to another...

If possible use a wire feed welder 'with gas' (MIG) It is much easier to see what you are doing, and requires much less clean up/grinding later..

Fasten a piece of leather or some other hard to burn material to the back of your welding hood to prevent any light from entering the hood from the back.. Light reflecting off the inside of the eye window, makes it 'very' difficult to see what you're doing.. And for 'me' seeing what I'm doing has always been the hardest part of welding..

Take a lot of breaks and work in a well ventilated area... Both fumes and eye fatigue creep up on you without realizing it when you are concentrating on your work....

Don't be afraid of welding.. Once you learn how, it's very handy to have a welder in your shop for fabrication or repair of this or that... Experiment on a couple scraps of the size and thickness you want to weld, and then you can get the amperage and feed rates right before you do the work that matters...

Jack,
We can learn together. I'm happy to compare pics of spattered, botched welds if you are (and hopefully the improvement over time!). At least with steel you can always grind and re-weld.
I'm taking Gerald at his word:

I still stand by that :)

Got over my fear, bought a 140A stick welder and welded end frames together. I can see a lot of grinding in my future! The welds seem strong enough (I can jump up and down on them).

The new masks make welding a LOT easier than I remembered it from 20 years ago. You can see what you are doing and then the glass darkens up as the arc gets thrown. Sure beats ducking behind the old smoked glass when the arc was struck!

I'd like to ask a question to those considering bolting parts of their frame. I am also looking at bolting the frame but my channel wall's arn't parellel, most of the small stuff has taper,

see 76x38:
http://www.roymech.co.uk/Useful_Tabl...s/chan_dim.htm

Question, bolting against the inner wall of the tapered channel, where can I source the special tapered nuts? I'm in UK and haven't found anywhere. I guess last ditched effort I could tap.

g

You need taper WASHERS not nuts.

Try http://www.brooksforgings.co.uk/squa...er-washers.asp

A section of the flange itself will make the washers you need.
If you turn the flange 180 degrees it will cancel out any taper exactly.
Just cut up the flange and drill some holes for your washers.
It might be prudent to drill the holes first then chop it up last though.

I'm pretty sure this idea is already on the forum somewhere, probably where I learnt it in the first place !

Regards
Ross

Just out of curiosity, if the machine needs to be able to be moved, why not modify the base and weld some torsion bar suspension arms to it? When it comes time to move it, jack up each side, drop the swing arms, bolt on the wheels, install the removable tongue and hook up the lights! I think that these machines could be easily adapted for transport with a little planning.

Add some double wishbone swing arms, springs， absorbers & a V12 engine and you are good to go on the racing track! Write a G-code for the optimum path!

agree Joe:

I like that thought Ken :D

:)

http://www.mechmate.com/forums/attac...1&d=1232845354:)
http://www.mechmate.com/forums/showt...&postcount=116

Ha ha Well done Yuri...glad to see you are still around... show us some of your latest work.

welding rods
 

If you use 7018 LH rods they don't splatter like the 6010 mild steel rods. So you have alot less splatter to clean up and they are alot easier to learn how to weld with and are just as strong. Most structural welders use 6010 rods on there first pass as a filler rod its called a "root" pass. Then it is finished and capped off with 7018 LH rods. But all you will need is 7018 LH rods for these cnc projects.