Thread: Elliot 8-18 Surface Grinder

Originally Posted by Machtool

I figure they haven't been moved in 40 years

Nobody could get the bolts undone....

Ray,
I have been following your thread but upto now had nothing to contribute.
Have you thought of drilling out the holes to tapsize and rethreading the original threads with a tap? Might be worth a try before you step up to more desperate measures.
Whatever you decide to do, goodluck with the project.

Regards,
Peter

Hi guys, thanks for your input and comments. Phil, You're probably not far off the mark. I figured that those balance weights had not been moved/adjusted in a very long time, otherwise there would only have been crud built up from 1 wheel use, not 40 years of use! I had noted that they seemed pretty much at 120 deg separation but figured maybe the last wheel installed was a real good one and almost "perfectly" balanced and so that's where they got put, but alas probably not. It takes a 10" wheel, if you reckon I don't really need to balance it (if I buy reputable brand) then that's probably good enough advice for me. No I don't have a balancing setup but was going to look into making one if after putting this thing back together I deem it worthy. Hi Ray, Yep, I think I will mount this thing on the RT, make up a guide bush for the drill (to reduce it's chance of wandering) and drill through these holes, firstly with the correct tapping drill (as per Peters suggestion) and then attempt to tap. If that fails then I may look into an oversized hole and maybe a helicoil type system. Even if I don't use the balance weights, I would like to have this thing cleaner than it is. Also, I'm not sure to what sort of tollerances the spigot itself needs to be balanced in order for itself not to be a source of vibration. These remnant bolts probably will not be an issue given their size/weight and the fact that they are spinning very close to the spindle axis but who knows, I'm venturing in territory that I have never been in before. Cheers, Simon

Originally Posted by simonl

. No I don't have a balancing setup but was going to look into making one if after putting this thing back together

Doesn't that seal it, up until the time you actually have a balancing rig, why bother. Even with a 10" wheel, just dress it all over.

Originally Posted by Machtool

Doesn't that seal it, up until the time you actually have a balancing rig, why bother. Even with a 10" wheel, just dress it all over.

OK. Works for me! I'll move onto the next issue.... Simon

Originally Posted by Machtool

(4) Throw them in the bin and forget they were ever there.

You do know that arranged like they were at 120 degrees apart, they weren't performing any balancing function.

I don't think you got a balancing stand, with the machine? These days no one balances small wheels like that, its no longer required if you buy name brand wheels.

regards Phil.

That's good info thanks Phil.

I have a Churchill SG awaiting attention, 7" wheel. In the manual they go on about balance weights, how to set them up etc.

One less thing to have to think about!

Hi Simon,
I will add to what Phil said as well.
I was discussing making a balance jig with Percy at work (he is an ex Timken toolmaker) who haas done more surface grinding than I ever will and he just laughed saying that he hasn't balanced a wheel as long as he can remember.
He reckons proper setting up and a quality wheel well dressed and you can (and he does) get a great finish.

Phil

Originally Posted by simonl

Yep, I think I will mount this thing on the RT, make up a guide bush for the drill (to reduce it's chance of wandering) and drill through these holes, firstly with the correct tapping drill (as per Peters suggestion) and then attempt to tap.

I'd try an endmill first. I find them easier to line up.

(on the assumption that while the weights aren't needed any longer, having one empty hole and two half empty holes is going to make 2/10ths difference???*, it might not )

Stuart

*almost forgot what forum I was on. 2/10ths in this case meaning 2/10ths of SFA, not 2/10ths of a thou.

Hi Phil & Stuart,

Given the advice in the last few posts, I will (for neatness) drill out those offending holes and leave them clean. In fact I will drill out the 3rd hole too in order to keep it "reasonably" balanced. Since there are a total of 6 holes spaced at 60 deg apart, I will simply use an existing "good" hole to reference off using either a close fitting drill, end mill or even wind the appropriate tap all the way through and reference off that. I don't think these holes need to be super dooper precise.

PS I knew what you meant Stu!

Cheers,

Simon

Well I got the spindle back together again and now the head is back on the column. Its starting to look like a SG again...


I guess we will see how "Accuramatic" it still is soon....

Simon

I'd have to agree with Phil on the smaller wheels. Even the 12x2" i have been using are pretty damn good out of the box. One thing that will screw up your balance big time though is if you let coolant gather in the wheel. If your using coolant, turn it off first and let the wheel fling all the coolant out.

Ew

Starting to look like a real machine again Simon. Nice job !

I always fiddle around balancing wheels, doesn't take all that much time, and I've got the bits and pieces to do it. As to whether is makes a difference or not, it's hard to tell, Josh can get a mirror finish on the M2 and if there was even the slightest hint of vibration you wouldn't get that mirror finish.

As Ewan says, never run coolant with the wheel off, and let the wheel run on for a little while after the coolant is off.

So I guess we will see a wheel on there and some test grinding taking place in the next few days.

What size wheel does it take?

Ray

Hi Ray & Ueee,

In the manual it actually says to run the wheel for a further 10 minutes after turning coolant off if using thriugh the wheel coolant system. Do you guys use that?

Yesterday I cleaned the coolant tank. It was putrid to say the least! Came up looking ok. Coolant pump still in reasonable nick but will need further cleaning.

This thread will now be at a standstill for about 3 weeks now so zero chance of seeing some test grinding anytime soon. Two main issues to sort out before final assembly and test. (1) need to fit the new oiler I got from Phil. Need to make a small adapter to fit it. Not a biggie. And
(2) There seems to be a minor issue with hydraulic pump. When it runs but no oil circulating, it dumps through to the relief valve (which it does) but somehow it over pressurises the bearing lubrication oil feed and blows out the seal for the shaft. I think ill have to take it apart and have another look. I may have used too much hydraulic sealant and block the bearing lube return gallery. Once again not a huge issue.

Also I did a (rushed) preliminary test on spindle runout at the taper and got 0.02mm. Was hoping for less but who knows what sort of crashes its experienced in its life. I dont think its the bearings as no amount of levering on the spindle shaft showed any deflection on the indicator.

I have been reading about runout on precision spindles and bearings and how the high spots are marked on the spindle and the bearing races need to be installed accordingly. Not sure if this applies to tapered bearings though?

Cheers

Simon

Taper runnout won't really effect anything as you dress the wheel concentric to the spindle axis. Bit different from a fixed cutter like a milling cutter in that regards.

I meant to say before, measure up your spindle taper. I have an arbor here that i got with the Blohm that is too small, you may get lucky!

Ew