cylinder end cap

[geoff walker 1Participant @geoffwalker1]

Hi All,

I have a piece of BMS plate 1/8" thick and using it I want to make a cylinder end cap.

The cap needs to be 34mm O/dia and have a spigot 20mm dia and 1mm long to fit the cylinder bore.

Any ideas on how to hold and machine.

I have an idea but thought I would ask first to see if anyone has a better idea.

Thanks Geoff

[geoff walker 1Participant @geoffwalker1]

[Nick WheelerParticipant @nickwheeler]

Wouldn't it be simpler to machine it from bar and part it off?

[SillyOldDufferModerator @sillyoldduffer]

If you mean like this:

I'd saw a square out of the plate and take the corners off with a file leaving a rough octagon big enough to make a 34mm disc. Then I'd super-glue the octogon to a round bar held in the chuck. I'd turn the 1mm deep spigot first, and then round off the rest of the cap.

Take it gently and the super-glue will hold the interrupted cut, (may not be necessary to file the octogon first, but it reduces the clonking!)

Super-glued parts can be separated by boiling, blowlamp, or soaking in acetone (aka nail varnish remover).

Dave

[Roderick JenkinsParticipant @roderickjenkins93242]

I'd make it as round as I can by hand, super glue it to a face plate and then creep up on it with a very sharp tool. A bit of warmth should break the glue joint.

HTH,

Rod

Edit:  Just like Dave really .  Mind you if  I had a bit of bar big enough to hold in the chuck I'd make it from that, as Nichols suggests

Edited By Roderick Jenkins on 27/04/2019 17:59:54

[EmgeeParticipant @emgee]

Roderick and Dave you have some excellent super glue, what make and type please ?
Those I have would be useless for such purpose.

Emgee

[JasonBModerator @jasonb]

Same as Dave and Rod, if you have any doubts about your glue the tailstock can be used to hold a pressure plate against the part while turned. I tend to use Mitre bond or the small 5mm bottles of Loctite superglue

[David George 1Participant @davidgeorge1]

Hi Geoff I would hold in 4 jaw turn boss leaving outside till later and counter bore a 10mm conterbore as deep as the boss for a centre support. I have a piece of 10mm dia. silver steel with a centre in it to push against jobs. Take out if 4 jaw chuck and hacksaw of corners clean up and glue to a bar with super glue. Hold in place with centre support and Finnish outside diamiter and face.

David

[SillyOldDufferModerator @sillyoldduffer]

Posted by Emgee on 27/04/2019 18:04:58:

Roderick and Dave you have some excellent super glue, what make and type please ?
Those I have would be useless for such purpose.

Emgee

I've done OK with cheapo Poundshop glue as well as more expensive brands. The trick is cleanliness and fresh, in-date, glue. Oil weakens super-glue severely, so any suspicion of grease and I wash the metals with warm water and a spot of detergent, then rinse and wipe off with Meths. Even clean metal is wiped with Meths before using super-glue.

As often as not super-glue metal to metal joints are embarrassingly strong when I try to break them. Although cleanliness may be the most important factor, super-glue seems to 'go off' fairly quickly; for me new glue seems more reliable.

Dave

[not done it yetParticipant @notdoneityet]

I would not start with BMS – it will likely warp when you remove the surface skin and fall off its substrate.

[Speedy Builder5Participant @speedybuilder5]

As soon as you glued it to a boss and mounted into a chuck etc, bring a rotating centre up to bear onto the plate for extra support.

[geoff walker 1Participant @geoffwalker1]

Hi All,

Many thanks for all your replies, very useful. Would have replied sooner but we had a tribal tsunami (aka the grand kids) last night so not much time for internet chat!

Yes I was thinking probably have to get it roughly round then bond the plate in place and as Rod said "creep up" on it and take by surprise.

Will use the tailstock for support. I like Davids idea of using a shallow counterbore.

I'll have a go in the week and report back

Big T again to all Geoff

[HopperParticipant @hopper]

You could soft solder it to a stub mandrel rather than glue it. Much stronger.

You could hold your square of plate in the 4-jaw, face it, put the spigot on it then make a stub mandrel smaller diameter than the finished end-cover's OD. Then put a recess in the end of the stub mandrel for the spigot to fit into to help hold job in place. Then turn the square down round to finished OD and face the final surface.

[geoff walker 1Participant @geoffwalker1]

Hi All,

No big deal this but as you guys were kind enough to offer advice I thought I would show the results.

I was surprised just how easy, by heating, it was to break the superglue joint between the cap and the boss.

Jobs a good 'un, thanks again Geoff

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