Tool post grinder

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Basil

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After my post on finishing crank journals for the Seal Major 30cc I got looking at grinding. I plan on putting this engine to use in a boat also I have plans to build more high performance engines so hardened steels will be required. Nothing much was popping up on Ebay and what was was in a sorry state. After a not very satisfactory result with an angle grinder I started to check out the Hemmingway tool post grinder and asked my wife to get me one for Christmas, I don't think she was planning that kind of expenditure but she agreed being totally clueless on what else to get me. Work stopped on the Seal major and I went full on with the new project.
Casting were very good and I really think they do a great job on the blueprints. Included are a few pictures of the project. A few little deviations from the design, definitely not required but if your going to build something why not make it your own. I didn't do a very good job of documenting the build being in a rush to put the grinder to use. Fire ahead with any questions.
 

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More pictures. Very happy with the results. The last picture of the big end journal was with the angle grinder setup which gave a notched cut finish due to slight bearing play in the head. I did have the lathe ways covered some when I did the machining. The residue left behind is a very fine grit especially when dressing the wheel. Definitely after witnessing this I'm going to take even more precautions going forward. Both for the machine and my health. 👍
 

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Interesting. Can you elaborate on the spindle design in terms of bearing layout, like how play is adjusted out.
And how do you increment the wheel depth of cut itself? Like how fine an infeed can you make & what controls it?
 
No problem Peter, I decided to take it apart again anyway to check on everything, also I had noticed some roughness in the bearing after about 30 minutes use and wondered if the pre-load was too much. A wavy washers is used to accomplish this. The inner or outer distance piece machined to determine how much this washer gets compressed.
In the rush to get the unit grinding on metal I grabbed any sealer off the shelf, not being able to put my hands on the RTV. I wanted to put something on the joint between the motor mount casting and the toolpost casting. I figured Locktite pipe sealer should work. Its was past midnight so not the brightest spark at that hour! It did seal but something else went on and it got dragged in with the oil and deposited itself on all the races. TEFLON !
Probably didn't help not giving it enough time to properly setup.
Carb cleaner would not touch it. MEK sorted it though.
I did decided to switch over to shielded bearings with the inner oil side shield removed. £5 in bearings and a very easy fix. Smooth a silk again! Well happy and won't be doing that again any time soon!
 

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Thank you for the pics.
So I take it you are in-feeding the entire grinder assembly with your cross slide? Or maybe on compound & set at high angle so you get fine depth of cut? Do you have any independent way of measuring infeed so as to feed small amounts & minimize reliance on conventional dials, backlash etc? Sorry for all the questions, I've been trying different things with my TPG. Unfortunately that beast does not play well in combination with tailstock support the way I see you are using yours.
 

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After my post on finishing crank journals for the Seal Major 30cc I got looking at grinding. I plan on putting this engine to use in a boat also I have plans to build more high performance engines so hardened steels will be required. Nothing much was popping up on Ebay and what was was in a sorry state. After a not very satisfactory result with an angle grinder I started to check out the Hemmingway tool post grinder and asked my wife to get me one for Christmas, I don't think she was planning that kind of expenditure but she agreed being totally clueless on what else to get me. Work stopped on the Seal major and I went full on with the new project.
Casting were very good and I really think they do a great job on the blueprints. Included are a few pictures of the project. A few little deviations from the design, definitely not required but if your going to build something why not make it your own. I didn't do a very good job of documenting the build being in a rush to put the grinder to use. Fire ahead with any questions.
Hello,
How was the finish using that wheel and grinding method ?
Thank You
Alec
 
No problem Peter, I decided to take it apart again anyway to check on everything, also I had noticed some roughness in the bearing after about 30 minutes use and wondered if the pre-load was too much. A wavy washers is used to accomplish this. The inner or outer distance piece machined to determine how much this washer gets compressed.
In the rush to get the unit grinding on metal I grabbed any sealer off the shelf, not being able to put my hands on the RTV. I wanted to put something on the joint between the motor mount casting and the toolpost casting. I figured Locktite pipe sealer should work. Its was past midnight so not the brightest spark at that hour! It did seal but something else went on and it got dragged in with the oil and deposited itself on all the races. TEFLON !
Probably didn't help not giving it enough time to properly setup.
Carb cleaner would not touch it. MEK sorted it though.
I did decided to switch over to shielded bearings with the inner oil side shield removed. £5 in bearings and a very easy fix. Smooth a silk again! Well happy and won't be doing that again any time soon!
I wonder why the bearings are not of the angular contact type, with a method beyond a wavy washer to control preload.
I see you split the existing bearing outer race, I assume to show the 'munge' from the Teflon contamination.
 
I wonder why the bearings are not of the angular contact type, with a method beyond a wavy washer to control preload.
I see you split the existing bearing outer race, I assume to show the 'munge' from the Teflon contamination.
It looked initially like there was some flaking of the bearing race but on closer inspection it wiped off to a perfect polished finish.
I'm thinking for light duty operation it was considered adequate with standard bearings. We will see how it holds up.
 
Thank you for the pics.
So I take it you are in-feeding the entire grinder assembly with your cross slide? Or maybe on compound & set at high angle so you get fine depth of cut? Do you have any independent way of measuring infeed so as to feed small amounts & minimize reliance on conventional dials, backlash etc? Sorry for all the questions, I've been trying different things with my TPG. Unfortunately that beast does not play well in combination with tailstock support the way I see you are using yours.
Yes, Just on the cross slide. I have not tried it yet with the compound. I do like the cross slide indicator. Is the block held with a stud?
 
The block is pretty simple - machined from aluminum & has 2 neodium magnets glued in a recess in the base. It seems firm enough that it doesn't move under operation & makes for quick, adjustable setups. I have a 10ths indicator mounted & its really quite revealing. Just breathing on the dials or locking the carriage can move the saddle in or out 'a lot' relative to what we are probably trying to accomplish with grinding in general. If you have loose ways the needle will vibrate on either side of the actual position. Personally I'm of the opinion you need something like this for grinding unless you can count on the angled compound setting setup to make small incremental in feed equivalents. A DRO would be better but typically they are 0.0005" & still some dead band in there before the next increment lights up. That's the whole grinding issue isn't it? Making a part shiny is one thing. Hitting a target dimension to close tolerance (and still with desired surface finish) is the real challenge.
 
Can you give some detail of the grinding wheel used please, size, grade and rpm.
These are the grinding wheels that came with the kit. 60 is the grit. RPM's of the grinder are 5,900/ 7,200 /26,200 depending on the pulley settings.
The large grinding wheel for external grinding is 3"X 0.5.
 

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What is the power & rpm rating of your motor? You vary grinding wheel speed entirely through pulley/belts right? (ie. no variable speed control on the motor itself).
 
No speed control . 3 speeds all by different pulley sizes. The large high speed pulley for internal grinding. 250W Approx. 3000RPM. The internal wheels are very small, about 0.6"
 

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You use compound for just chain the angle you see durrant manual.
I upload a durrant manual he year ago

Dave

After my post on finishing crank journals for the Seal Major 30cc I got looking at grinding. I plan on putting this engine to use in a boat also I have plans to build more high performance engines so hardened steels will be required. Nothing much was popping up on Ebay and what was was in a sorry state. After a not very satisfactory result with an angle grinder I started to check out the Hemmingway tool post grinder and asked my wife to get me one for Christmas, I don't think she was planning that kind of expenditure but she agreed being totally clueless on what else to get me. Work stopped on the Seal major and I went full on with the new project.
Casting were very good and I really think they do a great job on the blueprints. Included are a few pictures of the project. A few little deviations from the design, definitely not required but if your going to build something why not make it your own. I didn't do a very good job of documenting the build being in a rush to put the grinder to use. Fire ahead with any questions.
 
Durrant? My thinking would be just to get finer adjustment, compound set at 45deg. And grinding tapers. My Myford has some wear so is I can hold a thou. I'm very happy.
 

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